20020459 Ver 1_Complete File_20010912

O? . AT?9 Michael F. Easley, Governor
Q William G. Ross Jr., Secretary
02 7 North Carolina Department of Environment and Natural Resources
j r Gregory J. Thorpe, Ph.D.
Acting Director
vp°??s• Division of Water Quality
September 12, 2001
Mr. E. David Franklin
Chief, NCDOT Team
US Army, COE, Wilmington District
Post Office Box 1890
Wil nh Carol ina 28402-1890
Dear .
Re: Action ID No. 200100746
This correspondence is in reference to the proposed Clayhill Farms Mitigation
Bank, located in Jones County, being developed by the North Carolina Department of
Transportation. In response to your request that one individual be designated to represent
the Division on the Mitigation Bank Review Team, I am naming Mr. Mac Haupt as that
representative.
Please note that other members of the Division may attend meetings of the MBRT,
and participate in discussions. However, the Division's position on each issue will be
coordinated by Mr. Haupt and delivered after consultation with other members of the
Division.
The Division is committed to fostering an environment that is conducive to the
establishment of high quality private mitigation banks. Please let me know if the Division
can be of assistance in implementing a thorough and timely review process.
Sincerely,
Gregory J. Thorpe, Ph.D.
cc: John Dorney, Wetlands/401 Unit, DWQ
Jim Mulligan, Washington Regional Office, DWQ
David Timpy, Wilmington Regulatory Field Office, USACOE
file
INMEW
Wetlands Restoration Program 1619 Mail Service Center Raleigh, NC 27699-1619 [phone] Customer Service
320 West Jones Street Raleigh, NC 27603 Fax: [phone]'21 1 800 623-7748
,SEP-0,5-2001 14:37 USACOE/REG DIVI/NCDOT 910 251 4967 P.02i03
May 22, 2001
Regulatory Division
Action ID No, 200100746, Clayhill Frams Mitigation Bank
SEE DISTRIBUTION
Dear Colleague:
This correspondence is in reference to the Clayhill Frams Mitigation Bank that is being
developed by the North Carolina Department of Transportation (NCDOT), located in
southwestern Jones County, North Carolina. The purpose of this letter is to formally establish
the Mitigation Bank Review Team (MBRT) for this project.
Pursuant to 60 FR 228, p.58610, paragraph 3., Agency Roles and Coordination,
collectively, the signatory agencies to the banking instrument will comprise the Mitigation Bank
Review Team. Representatives from the U.S. Army Corps of Engineers (CE), U,S.
Environmental Protection Agency (EPA), U.S. Fish and Wildlife Service (FWS), National
Marine Fisheries Service (NMFS), and the Natural Resources Conservation Service (NRCS), as
appropriate given the projected use of the bank, should typically comprise the MBRT. In
addition, it is appropriate for representatives from State, tribal and local regulatory and resource
agencies to participate where an agency has authorities and/or mandates directly affecting or
affected by the establishment, use or operation of a bank. This may include the North Carolina
Division of Water Quality (DWQ), Division of Coastal Management (ACM), and the Wildlife
Resources Commission (WRC).
in this regard, we are inviting your agency to join the MBRT for this mitigation bank.
If you wish to participate as a member of this MBRT, you should designate a specific
representative of your agency to serve on the MBRT and notify us in writing within 30 days of
your receipt of this letter.
Thank you for your time and cooperation. If you have any questions, please contact
Mr. Dave Timpy, Wilmington Regulatory Field Office, telephone [phone].
Sincerely,
FILENAME :CLAYHILLMBRT3
CESAW-11..G /s
MAIL
CESAW-R /FIL
E. David Franklin
Chief, NCDOT Team
4-0,5-2001 14 : 37
DISTRIBUTION'
USACOE/REG DIVI/NCDOT
Mr. William L. Cox, Chief
Wetlands Regulatory Section - Region IV
Wetlands, Oceans, and Watersheds Branch
U.S. Environmental Protection Agency
Atlanta Federal Center
100 Alabama Street, S.W.
Atlanta, Georgia 30303
Mr. Garland Pardue
U.S. Fish and Wildlife Service
Fish and Wildlife Enhancement
Post Office Box 33726
Raleigh, North Carolina 27636-3726
Mr, David Rackley
NMFS
NOAA
219 Fort Johnson Road
Charleston; South Carolina • 29412-9110
Mr. Ron Sechler
National Marine Fisheries Service
Pivers Island
Beaufort, North Carolina 28516
Mr. John Dorney
NCDENR-DWQ
Wetlands Section
1621 Mail Service Center
Raleigh, NC 27699-1621
Mr. Doug Huggett
Division of Coastal Management
North Carolina Department of Environment,
Health, and Natural Resources
Post Office Box 27687
Raleigh, North Carolina 28557-7687
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910 251 4967
Mr. Frank McBride
North Carolina Wildlife Resources
Commission
Post Office Box 118
Northside, North Carolina 27564
Mr. Matthew R. Flint, State Biologist
U.S. Department of Agriculture
Natural Resources Conservation Service
4405 Bland Road, Suite 205
Raleigh, North Carolina 27609
P. 03/03
TOTAL P.03
N ATFRQ Michael F. Easley, Governor
William G. Ross Jr., Secretary
1/'1 Gy North Carolina Department of Environment and Natural Resources
? r
> ?„JW`/? =1 Gregory J. Thorpe, Ph.D.
p -C Acting Director
Division of Water Quality
Memorandum
To: Greg Thorpe
From: Ron Ferrel?J
Subject: Clayhill Farms Mitigation Bank
Date: September 12, 2001
The Corps of Engineers is requesting Division participation in the Clayhill Farms
Mitigation Bank in Jones County. The bank sponsor is the North Carolina Department of
Transportation.
I recommend Mac Haupt of our program be the Division contact for this mitigation bank.
We have prepared and attached a letter for your signature recommending Mac as the
contact. If you have any questions, please don't hesitate to call.
A
?,ICL?Et?
Wetlands Restoration Program 1619 Mail Service Center Raleigh, NC 27699-1619 [phone] Customer Service
320 West Jones Street Raleigh, NC 27603 Fax: [phone] 623-7748
January 10, 2002
Mr. David Timpy
US Army Corps of Engineers
P.O. Box 1890
Wilmington, NC 28402-1890
Re: Clayhill Farms Mitigation Bank
Dear Mr. Timpy,
The Division of Water Quality has had the opportunity to review the Clayhill Farms Mitigation Bank
Prospectus (April 2001)and Final Mitigation Plan Report (July 1999). In addition, the comments in this
letter include observations from a field visit on October 24, 2001.
Prospectus: April 2001
The Division of Water Quality must see documentation that the proposed mitigation bank is consistent
with the Basinwide Restoration Plan (Administrative Code- 15A NCAC 02R.0302) for the White Oak
River basin. The Division has had the opportunity to review the prospectus and has the following
comments:
2.2 Mitigation Bank Review Team Identification- the Division recommends that Marine
Fisheries be included in the Mitigation Bank Review Team.
3.4.2 Riverine Wetland Credits- the Division does not believe planting of the Atlantic White
Cedar (AWC) in the proposed areas will be successful. In most cases, AWC is found
growing in organic soils. The area of planting proposed is mineral soil, and the
Division questions whether the hydroperiod for the proposed area will be sufficient to
sustain AWC.
3.8 Preliminary Credit Calculations- each credit in a proposed mitigation bank must include a
minimum of one acre of restoration or creation (15A NCAC 2H .0506 h-4).
3.9 Proposed Schedule for Bank Completion and Credit Release- the following credit release
schedule is endorsed by the Division of Water Quality:
15%-contingent upon approval of the final mitigation plan, approval and
signature of the MBI, recordation of the conservation easement, and
establishment of financial assurances,
10%-approval of V year monitoring report,
10%-approval of 2nd year monitoring report,
10%-approval of 3`d year monitoring report,
15%-approval of O year monitoring report,
15%-approval of 5`'' year monitoring report,
25%a-final approval by MBRT.
4.1 Propmed Service Area- the Division approves of the proposed service area for the Clayhill
Farms Mitigation Bank.
4.3.1 Wetland Hydrology- the Division's position on monitoring wetland hydrology is to
compare the restored site's annual hydroperiod to the reference wetland's hydroperiod,
4.3.3 Stream Monitoring- the Division of Water Quality stream monitoring is referenced in the
Interim, Internal Technical Guide Summary-Benthic Macrovertebrate Monitoring Protocols for
Compensatory Stream Restoration Projects, May 10, 2000; and the Internal Technical Guide for
Stream Work in North Carolina. In addition, the Division supports the Draft Stream Mitigation
Guidance as proposed by the US Army Corps of Engineers.
Final Wetland and Stream Mitigation Plan: July 1999
The Division has had the opportunity to review the Final Wetland and Stream Mitigation Plan
and has the following comments:
Section 3.4.3:
DRAINMOD- in the future, the Division would like to see the technical information included in
agency review copy for both the Drainmod and the surface water models.
Section 3.5.3:
For stream restoration projects, the Division prefers to see a morphological table as shown in
the Internal Technical Guide for Stream Work in North Carolina. The Division is interested in what
sediment calculations were utilized for determining the entrainment calculations. The stream is a sand
bed stream and the standard calculations utilized for most stream restoration projects in the state (in
piedmont and mountain physiographic regions)are for gravel and cobble bed streams.
The Final Mitigation Plan shows stream restoration for approximately 7,400 linear feet. The
Division gives stream mitigation credit for perennial streams only. After the site visit and review of the
plans, the Division believes that there is not 7,400 linear feet of potential restorable perennial stream on
site. The Division recommends beginning the stream restoration section of the project at station 40+00.
Section 4.1.4: Proposed Hydraulics
This section proposes that the feeder ditches that drain into Billy's Branch will be partially
filled (to .5 feet below grade) at the downstream end of the ditch. The Division recommends filling in
the entire ditch. In addition, with only one plug the Division believes there is a risk that the plug will be
blown out.
If the ditches are plugged, what about the adjoined area immediately adjacent to the ditch with
regards to wetland restoration acreage?
The plan refers to a number of monitoring wells. The Division would like to see the data for
the monitoring wells. Several years have passed and there should be documentation that hydrology has
been removed from the site.
Section 4.2.2: Proposed Communities
The Division sees this site as a wet flat woodland grading into a 1" order stream by the end of
the site. Therefore, the Division's position on the reference areas is that most of the site is a non-riparian
wetland while the reference areas are located in riparian areas. The Division would like to see a
reference area located in a non-riparian wetland setting.
Section 6.0: Success Criteria
The Division's position on hydrological success is tied to the reference site. Success is
achieved when the hydroperiod for the restored site matches the hydroperiod for the reference site. The
hydroperiod is examined on an annual basis not just during the growing season. When the restored
hydroperiods line is no more than 15% lower than the reference site, the site demonstrates hydrologic
success.
Monitoring
The Division concurs with the length of wetland monitoring, while the stream monitoring
should follow the guidelines in the Interim Internal Guidance for Stream Work in North Carolina
mentioned above.
Section 7.0: Mitigation Ratios
The mitigation credits for the Clayhill Farms Mitigation Bank as pertaining to the Division of
Water Quality guidelines are elucidated below.
Credits are based on the following formula:
Credits= R/2 + (E/4R * R/2) + (P/5R * R/2)
Given in the Conclusion (9.0), the Mitigation Plan proposes:
Preservation= 155.9 acres
Restoration= 97.7 acres
Enhancement= 1.8 acres
Using the formula:
Credits= 97.7/2 + (1.8/390.8 *48.85) + ( 155.9/488.5 *48.85)
= 64.67 total Credits
Therefore, each credit will contain:
97.7/64.67= 1.51 acres of restoration,
1.8/64.67= 0.027 acres of enhancement,
155.9/64.67= 2.41 acres of preservation.
Thank you for the opportunity to comment. If you have any questions or comments, you can contact me
at [phone].
Sincerely,
Mac Haupt
Implementation Coordinator
DWQ-Wetlands Restoration Program
Cc: John Hennessy, DWQ 401/Wetlands Unit
Debra Sawyer, DWQ WaRO
Kathy Matthews, EPA Region 4
William Wescott, NCWRC
David Cox, NCWRC
Tom McCartney, USFWS
Ron Sechler, NMFS
Kelly Williams, NCDCM
Phillip Todd, NCDOT
Memorandum
To: Greg Thorpe
From: Ron Ferrell
Subject: Clayhill Farms Mitigation Bank
Date: September 12, 2001
The Corps of Engineers is requesting Division participation in the Clayhill
Farms Mitigation Bank in Jones County. The bank sponsor is the North
Carolina Department of Transportation.
I recommend Mac Haupt of our program be the Division contact for this
mitigation bank. We have prepared and attached a letter for your signature
recommending Mac as the contact. If you have any questions, please don't
hesitate to call.
September 12, 2001
Mr. E. David Franklin
Chief, NCDOT Team
US Army, COE, Wilmington District
P.O. Box 1890
Wilmington, NC 28402-1890
Dear Mr. Franklin,
Re: Action ID No. 200100746
This correspondence is in reference to the proposed Clayhill Farms
Mitigation Bank, located in Jones County, being developed by the North
Carolina Department of Transportation. In response to your request that one
individual be designated to represent the Division on the Mitigation Bank
Review Team, I am naming Mr. Mac Haupt as that representative.
Please note that other members of the Division may attend meetings of
the MBRT, and participate in discussions. However, the Division's position on
each issue will be coordinated by Mr. Haupt and delivered after consultation
with other members of the Division.
The Division is committed to fostering an environment that is
conducive to the establishment of high quality private mitigation banks. Please
let me know if the Division can be of assistance in implementing a thorough
and timely review process.
Sincerely,
Gregory J. Thorpe, Ph.D.
cc: John Dorney, Wetlands/401 Unit, DWQ
Jim Mulligan, Washington Regional Office, DWQ
David Timpy, Wilmington Regulatory Field Office, USACOE
ti
SUPPLEMENTAL APPENDIX TO THE MITIGATION PLAN
RESPONSE TO MBRT COMMENTS AND REVISIONS TO THE MITIGATION PLAN
Clayhill Farms Wetland and Stream Mitigation Plan
Introduction
The following discussion summarizes the results of issues raised by the MBRT, regarding the Clayhill Farms
Wetland and Stream Final Mitigation Plan Report (July 1999) and the Mitigation Bank Prospectus (April 2001).
The comments are summarized in a series of meeting minutes dated March 12002, March 4 2002, and April 30,
2002. This Supplemental Appendix will serve as an addendum to both the Mitigation Banking Plan and the
Mitigation Banking Prospectus. Section parameters enumerated in this addendum replace earlier provisions
described in both the Mitigation Plan and the Mitigation Bank Prospectus.
Mitigation Plan Report (July 1999)
3.4.3 DRAINMOD
NCDWQ Comment: In the future, the Division would like to see the technical information
included in agency review copy for both the Drainmod and surface water models.
NCDOT Response: The NCDOT will provide such technical information into the agency
copies.
3.5.3 Morphological Analysis of Billy's Branch
NCDWQ Comment: Stream restoration projects
1. The Division prefers to see a morphological table as shown in Internal Technical Guide for
Stream Work in North Carolina.
2. The Division is interested in what sediment calculations were utilized for determining the
entrainment calculations. The stream is a sand bend stream and the standard calculations utilized
for most stream restoration projects in the state (in piedmont and mountain physiographic
regions) are for gravel and cobble bed streams.
3. The Final Mitigation Plan shows stream restoration for approximately 7,400 linear feet. The
Division gives stream mitigation credit for perennial streams only. After the site visit and review
plans, the Division believes that there is not 7,400 linear feet of potential restorable perennial
stream on site. The Division recommends beginning stream restoration section of the project at
station 40+00.
NCDOT Response:
The NCDOT had not prepared the morphological table referenced by NCDWQ since the
NCDOT Plan Report was completed in July 1999, almost two years before NCDWQ had
Clayhill Farms Supplement
5/23/2002
Addendum
developed and published their internal Guideline (April 2001). The NCDOT is preparing the
morphological table for this project and will provide it at the next meeting.
2. The sediment calculations used were to derive shear stress for the reference stream and to
manipulate the design stream's slope and thus meander length and radius of curvature to
approximate the same shear stress. Grade control structures are being provided where the valley
slope increases and width decreases. Comparison of velocities for the bankf ill and 2-year storm
indicate that the banks will be stable (assuming sand-loam soils) when vegetated with mixed
grasses. This is based upon hydraulic modeling using HEC-RAS and procedures of the NC
Erosion and Control Planning and Design Manual. The attached memorandum (LandMark
Design Group, January 14, 2002) explains these issues in greater detail and was reviewed and
approved by NCDOT's Hydraulics Unit.
3. The US Army Corps of Engineers has held public forum on November 15, 2001 in Smithfield
during which they discussed situations that would require mitigation for Nationwide Permits.
During that PowerPoint presentation, the USACE presented a slide that stated that the
compensation requirements apply to both perennial and "high quality stream channels." The
District then provided the following clarification:
• Perennial and high quality stream channels:
o Presence of aquatic life such as fish and macroinvertebrates
o High quality channels can include both perennial and intermittent
stream channels."
The NCDOT therefore believes it is essential to document the amount of perennial and
intermittent stream length restored on site given federal permitting policies and guidance. In
addition, the NCDOT believes, based on the Jones County Soil Survey, that a stream extended to
the property's western boundary prior to agricultural use. As such, the proposed restoration
approach is a complete ecological-system restoration approach. For clarity, the NCDOT
proposes the following demarcation for perennial and intermittent restoration consistent with the
Division's recommendation for the limit of perenniality:
Intermittent Stream Restoration: 3,000 if (stations 10+00 to 40+000.
Perennial Stream Restoration: 5,262 (stations 10+00 to 92+62).
NOTE: SEE ALSO MITIGATION BANK PROSPECTUS SECTION 3.4 OF THIS SAME
ADDENDUM FOR ADDITIONAL INFORMATION REGARDING PERENNIALITY.
4.1.4 Proposed Hydraulics
EPA Comment: Ditch Filling Methods
The EPA's letter of August 6, 1999 stated that "...the ditches on the property be completely
filled, if possible. rather than plugged.
Clayhill Farms Supplement
5/23/2002
Addendum
NCDOT Response: The NCDOT's current design plans illustrate plugging and filling the
agricultural ditches rather than only plugging them. The eastern most three ditches will be filled
to the elevation of the fields. The western most seven ditches will be filled to within 0.5 of the
elevation of the fields. The 0.5 foot swale remaining is necessary to transport surface ponding
from the fields. As noted in the mitigation planning document Table 6 (page 21) for Clayhill
Farms, if the ditches were filled to the surface, then these fields would be ponded 40 out of 40
years. This design feature remains consistent with mitigation planning document except the
entire length of each ditch will be filled to within 0.5 feet of the surface rather than using ditch
plugs set 0.5 feet below the elevation of the surrounding farm field.
NCDWQ Comment: The NCDWQ inquired if the farm ditches had intercepted more permeable
sand layers? If so are the ditches going to first be lined with an impermeable lens prior to being
filled to the desired elevation?
NCDOT Response: We have found that some of the ditches have intercepted the more
permeable layers. Specifically, (counting ditches from west to east):
• Ditches 1-7 have intercepted the sand layer
• Ditches 8 and 9 did not
• Ditches 10 and 11 have intercepted the sand layer
Ditches 1-7, 10 and 11 will therefore be filled with clays to within 1.0 foot of the surrounding
ground elevation. This action will insure that the ditches do not artificially drain the surrounding
land after being filled. The balance of ditch fill will be top soil/loam from the site.
NCDWQ Comment:
1. This section proposes that the feeder ditches that drain into Billy's Branch will be partially filled
(0.5 feet below grade) at the downstream end of the ditch. The Division recommends filling the
entire ditch. In addition, with only one plug the Division believes there is a risk that the plug
will be blown out.
2. If the ditches are plugged, what about the adjoined area immediately adjacent to the ditch with
regards to wetland restoration acreage? The plan refers to a number of monitoring wells. The
Divisions would like to see the data for the monitoring wells. Several years have passed and
there should be documentation that hydrology has been removed from the site.
NCDOT Response:
1. Based upon comments from the USACE during a 1999 meeting to review the mitigation
planning document, the NCDOT agreed to fill the ditches their entire length, and to line the
western-most ditches with clay to avoid subsurface drainage effects. The agencies agreed to
maintain the ditches as 0.5' deep swales based on the results of the DRAINMOD analysis as
discussed in the Plan Report. Specifically, DRAINMOD showed that filling the ditches to the
surface caused ponding (38 of 40 years) for such long duration and frequency that it was felt the
tree plantings would likely not survive. By maintaining a Swale of 0.5' depth, saturation to the
Clayhill Farms Supplement
5/23/2002
Addendum
surface is maximized while ponding is minimized (page 20). Ponding however will still occur
(33 of 40 years). We believe that, over time, these minor swales will fill with debris and that
flooding will increase in frequency and duration. By this time however, tree seedlings should be
fully acclimated. All agencies present in the 1999 favored this approach.
2. The NCDOT has been monitoring the site for purposes of having a baseline of data to allow for
comparison to post-restoration data. This data has only been collected and stored. It has not
been analyzed for comparison to the wetland hydrology criteria. The site was confirmed to be a
Prior Converted cropland, and as such, is non jurisdictional, and does not require monitoring for
wetland hydrology. The NCDOT can make the data available on the server for the agencies to
download and analyze at their own discretion.
4.2.2 Proposed Communities
NCDWQ Comment: The Division sees this site as a wet flat woodland grading into a 1' order
stream by the end of the site. Therefore, the Division's position on the reference areas is that
most of the site is a non-riparian wetland while the reference areas are located in riparian areas.
The Division would like to see a reference area located in a non-riparian wetland setting.
NCDOT Response: The NCDOT is unaware of a habitat classified as "wet flat woodland"
(Schafale and Weakley,1990). We disagree with the NCDWQ that "most of the site is a non-
riparian wetland." The reference wetland stream site used for this study, less than 1.5 miles east,
is a first order stream and has signs of riparian wetlands. In addition, the Clayhill site has an on-
site, natural tributary, which joins with Billy's Branch from the north at station 61+60, making
Billy's Branch a second order stream. Robert E. Horton developed the stream order method.
Horton recommended that streams designated as ephemeral as well as those classified as
perennial be included in the network (A View of the River, Luna B. Leopold, 1994, Pages 223-
227), which confirms Billy's Branch classification as a second order stream.
5.0 Site Construction and Planting Requirements
Road Crossing the Northern Half of Site
The EPA's August 6, 1999 letter states: "There is a road shown on the figures, crossing the
northern half of the property. Will this road be removed, or will culverts be installed to improve
hydrology?"
NCDOT Comment: Neither the northern nor central road within the property will be maintained
nor improved by the NCDOT since use of these roadways is not anticipated to any substantial
degree during monitoring. Neither road is expected to be used during construction. It will be the
responsibility of the USFS to install culverts consistent with Federal and State silvicultural
requirements should they wish to maintain either or both of these roads.
Clayhill Farms Supplement
5/23/2002
Addendum 4
NCDOT Comment: The U.S. Forest Service, the likely recipient of the bank, has informed the
NCDOT that the bridge across Billy's Branch at the southeast portion of the tract is not
necessary.
Stream Restoration Project
NCWRC Comment: The NCWRC would like woody debris introduced into Billy's Branch to
provide additional aquatic habitat.
NCDOT Response: Root wads will be added into the Billy's Branch restoration project during
construction.
USACE Comment: The USACE voiced a concern that the water will be released before the
vegetation has had adequate time to become established.
NCDOT Response: The NCDOT will perform all of the construction and can afford to wait for
the vegetation to become established before releasing running water into the stream.
USAGE, EPA, and NCWRC Response: Concur.
6.1 Wetland Mitigation Monitoring
NCDWQ and USACE Comment: Wetland Mitigation Reference Site
NCDWQ and USACE requested that reference site(s) be utilized for wetland hydrology
monitoring and that those results be utilized, in some fashion, as surrogates for the wetland
hydrology success criteria for the Clayhill Bank. The NCDWQ suggested some manner of
"confidence intervals" around both the average water elevation and duration of saturation within
12 inches of the surface since variability between the reference and mitigation sites is inevitable.
NCDOT Response: The NCDOT has not seen any guidance related to the suggested hydrology
success criteria. While the NCDOT is willing to explore this issue with the MBRT discussing
further this concept, however, the NCDOT is not willing to tie hydrology of the reference
wetlands to success criteria for Clayhill Farms. The NCDOT recommended traditional
monitoring and success criteria without a reference wetland in its July 1999 mitigation planning
document. There were no comments received on the lack of a reference wetland for hydrology
nor any comments from the agencies about its monitoring and success criteria during that review
period.
The NCDOT is not aware of any scientific research that validates 1) whether such a comparison
can be made between a reference wetland system and a new constructed site, 2) what the
confidence intervals should be for such a comparison, nor 3) how to calculate them. The
NCDOT currently fiends an on-going research project with N.C. State University which involves
reviewing wetland hydrology in reference wetlands. The initial results of this academic project
Clayhill Farms Supplement
5/23/2002
Addendum
reveal inconclusive documentation on the ability to correlate reference wetland hydrology to
wetland mitigation sites.
The NCDOT is concerned that a new policy could dictate regulatory success or failure, while the
establishment of the procedures has not undergone scientific nor thorough regulatory review.
The concept has been used at Croatan Mitigation Bank and NCDOT agreed to this concept on a
test basis. The NCDOT believes Croatan may be a test site for such an experiment along with
the on-going research grant provided to N.C. State University.
EPA Comment: The EPA's letter of June 13, 2001 states: "We note that the prospectus
discusses the use of a reference reach to assist in the design of the stream restoration portion of
this project. EPA strongly recommends that the sponsor also identify and utilize at least one
reference wetland for comparison purposes during the planning, construction and monitoring
phases. The hydrology of the reference wetland should be used as a target for the restored
wetland areas. As the MBRT is aware, reference sites are useful in determining success or
progress in a mitigation area, especially during atypical years (such as drought or high water
years). The reference site(s) should be identified and described in detail in the mitigation plan.
Further, the MBRT should be provided the opportunity to conduct a site visit of the reference
site(s) and reference reach(es).
NCDOT Response: Two reference wetland sites were located and used during the planning and
design of Clayhill Farms (see Figure 1 and Section 4.2 Conceptual Planting Plan, Subsection
4.2.1 Reference Stands in the Mitigation Plan Report). These wetland systems were used for
potential plantings within the proposed wetland systems. Please note that one of the reference
wetland sites was the wetland abutting the off-site reference stream reach.
The NCDOT has identified two stream reaches which were used for reference reaches. These
reaches are noted in the mitigation planning document for the mitigation bank. The NCDOT will
present this data in a format similar to Appendix B.
Unfortunately, time was not available for inspection of the reference stream/wetland site during
the October 2001 on-site meeting. A site visit to the reference wetland can be arranged at the
convenience of the MBRT. The NCDOT response to the previous comment from the NCDWQ
and USACE addresses the use of wetland reference sites in evaluating the success or failure of
the groundwater hydrology of the wetland mitigation area.
NCDWQ Comment: Success Criteria
The Division's position on hydrological success is tied to the reference site. Success is achieved
when the hydroperiod for the restored site matches the hydroperiod for the reference site. The
hydroperiod is examined on an annual basis not just during the growing season. When the
restored hydroperiods line is no more than 15% lower than the reference site, the site
demonstrates hydrologic success.
Clayhill Farms Supplement
5/23/2002
Addendum 6
NCDOT Comment: The NCDOT has concerns tying the success criteria to a reference site. NC
State studies show a huge variability in performance between reference sites.
EPA Response: Agrees that the reference site should not be used to determine success.
However, recommends using a reference site as indices. For example, it will help to confirm
periods of drought.
NCWRC Response: Agrees with EPA.
USACE Response: Agrees with the EPA.
THE NCDOT Response: The NCDOT will locate and place a gauge in a reference site for
comparison only.
Allowance for Woody Volunteer Species
EPA Comment:The EPA has stated in their June 13, 2001 letter that: "In addition to the
requirement for survival of 260 5-year-old trees per acre, we recommend that the success criteria
state that red maple, sweet gum and loblolly pine should each consist of no more than 10% of the
total number of surviving trees."
NCDOT Response: The NCDOT requests the source of these numeric limits and the method of
their development since we are not aware of any scientific studies or regulatory policies related
to these criteria. Such limitations would require extensive management via the use of herbicides
and can be expensive since manual labor may also need to be used. NCDOT has used herbicides
on projects in the past where red maple, sweet gum and loblolly species are impeding growth of
planted trees.
The NCDOT is of the opinion that planted species are to assist in "jump-starting" succession by
creating a seed source for succession to oaks and other mast producing and hardwood species
beneficial to wildlife. As NCDOT has noted in its monitoring of other wetland mitigation sites,
there is a natural regeneration of these mentioned species from the site itself as well as from off
of the property. NCDOT has also shown through its monitoring of other mitigation sites that
planted species still survive even with the other species naturally regenerating. Therefore, the
NCDOT does not believe this suggestion should be included in the success criteria for Clayhill
Farms Mitigation Bank.
NCDOT Comment: The NCDOT was concerned with an EPA comment stated in their June 13,
2001 letter: "In addition to the requirement for survival of 260 5-year-old trees per acre, we
recommend that the success criteria state that red maple, sweet gum and loblolly pine should
each consist of no more than 10% of the total number of surviving trees." The NCDOT was
concerned that they would have to manually control unfavorable volunteer species at
considerable expense, even if those species were not harming the success of the target species.
Clayhill Farms Supplement
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Addendum 7
EPA Response: The EPA clarified that red maple, sweet gum and loblolly pine should consist
of no more than 30% of the counted surviving trees. The NCDOT does not need to manage
volunteer species.
NCDOT Comment: The NCDOT will continue with its existing protocols for monitoring its
mitigation banks and sites.
7.0 Mitigation Ratios
EPA Comments: Mr. Timpy spoke on behalf of comments he received via telephone from the
EPA. The EPA wished to reiterate that, as referenced in their August 6, 1999 and June 13, 2001
letters, they disagreed with the proposed mitigation ratios utilized in both the Mitigation Plan
Report and the Prospectus. They recommend that the ratios and policies provided in David
Lekson's June 27, 2000 letter be adhered to. Their specific comments are provided below:
EPA's August 6, 1999 Comment on Mitigation Plan Report
"EPA disagrees with the proposed mitigation ratios for upland enhancement and preservation
presented in Table 11 on Page 34. Although we recognize the importance of upland and riparian
buffers in protecting the wetlands from adjacent impacts, it is against EPA policy to allow
compensatory mitigation credit for upland restoration, enhancement, or preservation. EPA is
typically amenable to discussing the allowance of factors to lower the overall mitigation ratios
associated with specific aspects of the mitigation plan. In this case we believe that it may be
appropriate to acknowledge the functional value of the uplands by considering them as a stream
buffer, and adjusting the stream mitigation ratio as appropriate. However, we stress that the
allowance should be minimal, since these uplands don't appear to buffer any of the wetlands, and
buffer less than 50% of the streams on-site. Further, the riparian buffer would exist whether or
not credit is given for it. The riparian area adjacent to the restored stream is wholly within the
proposed mitigation area, intermixed with wetlands, and will be preserved regardless of whether
mitigation credit is given."
NCDOT Response: The NCDOT will propose using the ratios referenced for wetlands in the
June 13, 2001 letter from the EPA. Revised mitigation credits using these ratios and input from
NCDWQ are contained in NCDOT's response to NCDWQ's comments.
The NCDOT cannot propose stream credits based on "draft Interim Stream Mitigation
Guidelines for the State of North Carolina" because it does not have a copy of this document. It
is likely that the revised ratios for stream mitigation may include the benefits of upland buffers as
referenced in the EPA's August 6, 1999 letter.
NCDWQ Comment:The NCDWQ stated that their rules mandated that a credit must have at
least one acre of restoration. As such, ratios must be the greater of EPA's or NCDWQ's.
Clayhill Farms Supplement
5/23/2002
Addendum
NCDOT Response: The NCDOT will utilize Federal and State policies regarding mitigation
ratios to make a proposal on mitigation credits. However, NCDOT requests that the MBRT
provide guidance on whether these policies will be unified under the new guidance being
developed by the USACE and all MBRT agencies.
NCDWQ Comment: The mitigation credits for the Clayhill Farms Mitigation Bank as
pertaining to the Division of Water Quality guidelines are elucidated below.
Credits are based on the following formula:
Credits=R/2 + (E/4R * R/2) + (P5R * R/2)
Given in the Conclusion (9.0), the Mitigation Plan proposes:
Preservation = 155.9 acres
Restoration= 97.7 = acres
Enhancement = 1.8 acres
Using the formula:
Credits = 97.7/2 + (1.8/390.8 * 48.85) + (155.9/488.5 *48,85)
=64.67 total Credits
Therefore, each credit will contain:
97.7/64.67 =1.51 acres of restoration,
1.8/64.67 = 0.027 acres of enhancement,
155.9/64.67 = 2.41 acres of preservation.
oN?
NCDOT Response: Based on EPA's letter of June 13, 2001, the NCDOT understands that
credit calculations are as follows:
Restoration: 97.7 acres/1:1 = 97.7 credits
Enhancement: 1.8 acres/2:1 = 0.9 credits
Preservation: 155.9 acres/5:1 = 31.18 credits
Total= 129.78 credits
Therefore each credit will include
97.7/129.18 = 0.75 acres of restoration Qn,?crs?' ??
0.9/129.78 = .007 acres of enhancement C
31.18/129.78 = 0.24 acres of preservation
I , {j
C12 /"P The EPA also states "the MBI should also include the language recommended on Page 2 of the
June 27, 2000 (David Lekson's letter) letter, which generally states that two credits will be
debited from the bank for each acre of wetland impact. le iie
+=--'--
thftn-t-r4,_._
Clayhill Farms Supplement
5/23/2002
%\ddendum 9
The NCDOT is very interested in resolving the different methods of deriving credits and the
number of credits needed to offset each acre of impact.
EPA Comment: The WRP agrees to use the EPA's method to calculate wetland credits. The
WRP would like language that stipulates using 1.0 acre of restoration first before using other
compensation. The EPA suggested that credits be calculated individually for each type of
compensation provided.
USACE Response: The USACE feels that this is acceptable.
NCDOT Response: The NCDOT concurs with this suggestion. The credit calculation is
therefore as follows:
Restoration: 97.7 acres/1:1 = 97.7 credits
Enhancement: 1.8 acres/2:1 = 0.9 credits
Preservation: 155.9 acres/5:1 = 31.18 credits
Total= _ 129.78 credits
Upland Credit
NCDOT Comment:
The NCDOT proposes restoring upland areas within existing wetlands in exchange for a 4.5: 1 or
possibly 4:1 preservation ratio. Restoration of the upland areas will provide future Red-
cockaded Woodpecker habitat.
EPA Response: The EPA stated that a 4.5;1 ratio might be acceptab ant_postiibly a to ratio
if provided «?th suflicienl justilicalion. `hhe E?1':1 would deed to revie« this justification.
NCDOT Response: 'I Ile ivCDOT is proposing to restore (rephuit with trees) 44.1 acres of uplands;a
mesic pine 17atwoods, and preserve an additional .57.9 acres of uplandwoodlan&. A substantia"fpO'ttott
of the rest orati0Wol tip] ands'?vi11'occu'r adjacent to the r pariah area a?nrlg Billy's 13raneAppex' tma?el
1.800 linear feet of Billv's Branch abuts this upland restoration, which will have'?an average widtliiof
about 250' (from the top of stream bank): In addit ion. this area of "uplands," varies from the adjacent
wetland soil by a small variation in soil texture and Color. It is quite possible thatthis area will main" n
water table within 12 inches of the soil surface for 5"0 or more of the growing season. As SUCh, this
habitat prov°idesa broad continuum-from the uottomland hardwoods and wetland flatenvironrnents a
well as from the wetland pine flatwoods, thereh? completing restoration of all habitats in this %vatershc
Without resolving with the NIBRT a reduced ratio for wetland preservation, it is difficult for the N DOT
to support spending stale funds on replanting upland areas. regardless of the ecological value.
The preservation of forested uplands (a mixed stand of predominantly loblolly pine, oldest trees abet 36
year old) provides a number of benefits. This forest is potential foraging habitat for the Red Cockaded
Woodpecker: a Federally listed cndangered specie;. due to the forests'' age and species composition, "In
good, well-stocked pine habitat, sufficient Ioraging substrate can be provided on 80 to 125 acre
(refereltce, iioan LTSF?4'S, in k iti,_,ation Plan R.eport). Combined tivith the acreage of the upland
Clayhill Farms Supplement
5/23/2002
Addendum 10
torttion,a to f03 ?icres rttiild y 1 frestl Mist adte t sragin,
CDOT believes this issue, has merit because two active colonies of RCW giver lbserved n
mice Road 144' wthin'one mile of the Clayhill property in 1992,,
preservation, and testorlation of mesic pjhe 11,o gods will also increase th overall path s
forester coxtimuntty _at 6'6_C- ay 111 arms, Wetland and,5tream Nlitigation Bank, Th&4b" Y111-n, On
increase patch size lint also 'decrease tfic amount of edge habitat As foresYha?iitaf patch size ?nc?ea es;
vr: r x
decreasing to nt1n1bQfs jhroiigout the eastern seaboard;(fortxiari and Godron 186 and 3 ` Uepa . e t t
Agriciilhirc,and US'ForestServ?ce,i 98()): As patch' i s, raging efficiVnq v rrt
forest interior species
s a consequence of rest in 44. c c, oT; i d "t, ari er n ? do S7_ T44 P,,
s Q
upland forest (a total of 102 acres), the NCDOT requcests that the wetland preservation ratio be deere. c
from 5:1 to 4:1. This modif cat io itfthe ratio ,vinild g erg tee deli io _Val 7.7 credits de 14
fo#lor,ing ablc?
Table 1. Mitigation Ratios for Preservation Compared at 5:1 and 4:1
Wetland Preservation Type Acreage Credits at 5:1 Credits at 4:1
Mixed Pine Regeneration 148.5 29.7 37.1
Mixed mesic hardwood 3.6 0.7 0.9
Coastal Plain bottomland
hardwood 2.0 0.4 0.5
Total 154.1 30.8 38.5
References
Landscape Ecology. 1986. Richard T.T. Forman and Michel Godron. John Wiley & Sons, Inc.
Management of North Central and Northeastern Forests for Non-game Birds, Workshop Proceedings.
1980. US Department of Agriculture and US Forest Service, compiled by Richard M DeGraaf and Keith
F. Evans.
Mitigation Banking Prospectus (April 2001)
2.2 Mitigation Bank Review Team Identification
The NCDWQ recommends that Marine Fisheries be included in the Mitigation Bank Review
Team (MBRT).
NCDOT Response: The National Marine Fisheries Service (NMFS) was contacted by the U. S.
Army Corps of Engineers (USACE) about serving on the MBRT. NMFS chose not to participate
on the MBRT.
USACE, EPA, and NCWRC Response: Concur.
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Addendum
3.3 Location, Type, Acreage, and Condition of Proposed Debiting Resources
Reference to NCDOT Projects being considered for debits at the Bank.
USACE Comment: The USACE stated that the NCDOT has forwarded a letter to the NCDWQ
requesting compensation for the Jacksonville Bypass (TIP U-2107, sections A and D), which is
in HUC 03030001. As such, the references to this roadway project in Section 3.3 should be
deleted (both the bullet and in paragraph following).
NCDOT Response: The NCDOT will agree to this recommendation since it agreed in Item 4 to
the bank serving HUC 03020106. The NCDOT will revise Section 3.3 in the Prospectus
accordingly.
The Bank will serve the NCDOT projects within HUC 03020106.
3.4 Stream
Limits of Perenniality / Upstream Origin of Billy's Branch
NCWRC and NCDWQ Comment: Both agencies indicated their concern that the western
portion of Billy's Branch may be intermittent after restoration. The NCDWQ recommended
installation of velocity meter, as well as stream elevation gages, on Billy's Branch (at location of
existing bridge and near the upstream limits of perenniality).
NCDOT Response: The Soil Survey of Jones County, North Carolina (November 1981)
provides an aerial photograph of the site when timber was being harvested and prior to the
conversion of forest to agriculture (sheets 13 and insert on sheet 8). The western end of the
property, where agriculture would exist in the future, was in the process of being harvested, so
the ground is evident in the aerial photography. The Soil Survey indicates that the upstream limit
of the stream is 300+/- feet from the western limits of timber harvesting, which appears to
correlate with the western boundary of the site. The Soil Survey indicates that Billy's Branch is
intermittent until its confluence with Hunter's Creek. It is also interesting to note that the Soil
Survey depicts Hunter's Creek as intermittent too.
The NCDOT believes that, while the physical mapping is relatively accurate, the intermittent
determination is incorrect. For example, the off-site reference stream is also shown to be
intermittent in the Soil Survey (insert sheet 8). NCDOT's consultant visited this off-site
reference site on numerous occasions between Spring 1999 and Summer 2001. During each
visit, the off-site reference has always been found to contain flowing water, and therefore the
stream has been considered to be perennial. The same conditions have also always been
observed at Billy's Branch, the proposed mitigation reach. Both the off-site reference reach and
Billy's Branch were dry on the morning of the MBRT meeting (October 24, 2001), which we
believe is due to the sustained, low rainfall conditions in the area.
Clayhill Farms Supplement
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Addendum 12
The definition of perennial streams (blue line streams) used by the USGS is quoted in A View of
the River (Luna B. Leopold, 1994) as "Those hydrographic features which contain water
throughout the year except for infrequent and extended periods of severe drought."
Unfortunately, Mr. Leopold's personal examination of the mapping practices of the USGS field
staff responsible for compiling the mapping found that "blue lines on a map are drawn by
nonprofessional, low-salaried personnel. In actual fact, they are drawn to fit a rather
personalized aesthetic."
The USGS quadrangle illustrating the off-site reference reach indicates that it is perennial to its
upstream limit while it illustrates Billy's Branch to be intermittent upstream of the on-site bridge
(Figure 1, Mitigation Plan Report). This difference in mapping all of the off-site reference reach
as perennial and most of Billy's Branch as intermittent is contrary to the similarities in drainage
area of each stream. The off-site reference reach has a drainage area of 0.7 square miles
upstream of SR 1101 while Billy's Branch has a drainage area of 0.8 square miles upstream of
SR 1101 and 0.6 square miles within the Clayhill property. Based on the drainage area data, on
field observations of both the off-site reference reach and Billy's Branch and on the fact that the
USGS mapping of the reference reach correlates with field observations, we believe the USGS
and Soil Survey maps are incorrect regarding Billy's Branch, and that its correct classification is
perennial.
It is recognized, however, that some portion of the western half of Billy's Branch may in fact be
intermittent as the contributing drainage area decreases. It has been projected that the
intermittent stream begins at the upstream of the bend. The stream footage noted in the
prospectus corresponds to this determination.
The NCDOT still proposes to restore all of Billy's Branch because such restoration is
ecologically most advantageous for the site and drainage area. The NCDOT will perform stream
monitoring in some fashion to determine the limits of perenniality post-construction activities on
the stream. The length of any intermittent stream will be derived and subtracted from available
perennial stream credits. The NCDOT will work with the MBRT to derive a method of
evaluating perenniality and maintain a ledger of both intermittent and perennial stream length.
The NCDOT recommends that the MBRT allow the accounting for mitigation on the intermittent
stream since such credits may be needed on a permit-by-permit basis.
The NCDOT is currently monitoring two stream gages (elevation only). One of these gages has
been placed on Billy's Branch immediately upstream of SR 1101 while the second is located in
the area of concern regarding limits of perenniality (approximately 300 feet east of the existing
upstream limit of Billy's Branch).
NCWRC and USACE Comment: The agencies indicated that mitigation credits would not be
provided for restoration of an intermittent stream. The WRC and USACE indicated that they are
not requiring compensation for impacts to intermittent streams. The WRC stated that they could
only recall two instances when compensation for an "intermittent" stream was required, but that
the compensation was required because the applicant was insisting the stream was intermittent
Clayhill Farms Supplement
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Addendum 13
when the regulatory agencies felt it was perennial. As such, the issue was actually the limits of
perenniality.
NCDOT Response: The USACE has required compensation in the past for intermittent streams
on NCDOT projects when the stream reach was deemed to "ecologically significant". The
Wilmington District of the USACE held a seminar for the public on November 15, 2001 in
Smithfield during which they discussed situations that would require mitigation for Nationwide
Permits. During that powerpoint presentation, the USACE presented a slide that stated that the
compensation requirements apply to both perennial and "high quality stream channels." The
District then provided the following clarification:
• "Perennial and high quality stream channels:
o Presence of aquatic life such as fish and macroinvertebrates
o High quality channels can include both perennial and intermittent
stream channels"
Based upon the USACE most recent policies, and the NCDOT's experience on previous projects
in other river basins, the NCDOT believes the restoration of the entire reach of Billy's Branch is
both ecologically appropriate and prudent from a regulatory perspective. Should the USACE
require compensation for impacts to intermittent, high quality stream channels within this service
area, the NCDOT desires to have similar compensation available for consideration by the
MBRT. Again, the limits of perenniality will be evaluated post-restoration and credits of
perennial and intermittent stream will be accounted for separately.
NCDOT Comment: The NCDOT proposes classifying portions of the stream between stations
10+00 and 42+00 as intermittent. Downstream from this mark will be classified as perennial.
Credits will be calculated individually for intermittent and perennial segments. The NCDOT
would like to stipulate that the location of the intermittent/perennial boundary will be reevaluated
after restoration activities are completed.
EPA Response: The EPA concurs with the NCDOT.
USACE Response: The USACE concurs with the NCDOT.
3.4.2 Riverine Wetland Credits
NCDWQ Comment: The Division does not believe the planting of Atlantic White Cedar
(AWC) in the proposed areas will be successful. In most cases, AWC is found growing in
organic soils. The area of planting proposed is mineral soil, and the Division questions whether
the hydroperiod for the proposed area will be sufficient to sustain AWC.
NCDOT Response: The NCDOT originally proposed Atlantic white cedar because it was
concerned with the flooding/ponding, base on DRAINMOD, of water in the western portion of
Clayhill Farms Supplement
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Addendum 14
the tract. As noted in response to the meeting minutes on the prospectus, DRAINMOD predicts
flooding/ponding of the western portion of the site in 38 of 40 years.
The NCDOT recommended an AWC community because we believed the species would be able
to handle this hydroperiod successfully. The NCDOT reviewed information available from the
North Carolina Forest Service, Division of Forest Resources, together with information provided
by the U.S. Army Corps of Engineers, Norfolk District relating to numerous test plots of Atlantic
White Cedar (AWC) on both mineral and organic soils. Both agencies found that AWC can be
grown successfully on mineral soils such as those on the Clayhill Farms tract. This research
indicated however that the low survivability of AWC is due primarily to: 1) its lower growth rate
compared to primary successional tree species (red maple, sweet gum and loblolly pine), and 2)
herbivory. These constraints can be minimized by intensive management strategies, which the
NCDOT has evaluated and found to be unfeasible. Therefore the NCDOT agrees with the DWQ
recommendation to remove AWC from the planting plan.
The NCDOT proposes to replace AWC with Bald Cypress, to provide a headwater swamp forest.
This is virtually identical to a planting plan implemented by the NCDOT in the Pasquotank
Basin.
Length of Hydro-Period
The western portion of the Clayhill site is comprised of Torhunta and Pantego soils. These soils
comprise a Mapping Unit described by the USDA in the Soil Survey of the Jones County, North
Carolina (1981, page 5). Both soils in this mapping unit are very poorly drained. Both soils
typically contain headwater streams and headwater swamp forests. The USDA Soil Survey of the
Jones County, North Carolina illustrates this fact in Figure 2 (page 6), which depicts several
headwater streams originating in and traversing through these soils. Specifically, the illustration
notes that the headwater streams of the White Oak River (which would include Billy's Branch)
originate in this mapping unit.
DRAINMOD was used to evaluate the duration of saturation and ponding at the site. Given the
low permeability of these soils, field simulations for the 40-year modeling period show that post-
restoration ponding increases to a minimum of 38 years and maximum 39 years (depending on
the particular ditch modeled). These fields will receive, on average. 90 consecutive days of
flooding/ponding during the 40 years modeled (four ditches were modeled). It is for this reason
NCDOT suggests planting tree species that are able to tolerate extended inundation.
NCDOT proposes planting the headwater swamp forest in bald cypress, water tupelo, black
tupelo, overcup oak, swamp chestnut oak, and green ash. NCDOT has had success with a similar
headwater swamp in the Pasquotank river basin.
NCDOT Comment: The NCDOT would like to exchange Bald Cypress for Atlantic White
Cedar to provide a headwater swamp forest.
Clayhill Farms Supplement 5/23/2002
Addendum 15
USACE, EPA, and NCWRC Response: Concur.
3.8 Preliminary Credit Calculations
Wetland Credits
EPA's June 13, 2001 Comment on Prospectus
"In section 3.8, EPA recommends that the method for generating mitigation credits, agreed upon
by the MBRT at our June 1, 2000 meeting, be used to determine the number of available wetland
credits for each Phase (I! l for restoration, 2:1 for enhancement, 3:1 for creation, and 5:1 for
preservation). The method is outlined in David Lekson's June 27, 2000 letter. Stream credits
should be determined consistent with the draft Interim Stream Mitigation Guidelines for the State
of North Carolina. The MBI should clearly outline the calculation of mitigation credits for each
phase and each type of mitigation. Finally the MBI should also include the language
recommended on page 2 of the June 27, 2000 letter, which generally states that two credits will
be debited from the bank for each acre of wetland impact. In no case should the credit ratios be
less than 1:1."
NCDOT Response: The NCDOT will propose using the ratios referenced for wetlands in the
June 13, 2001 letter from the EPA. Revised mitigation credits using these ratios and input from
NCDWQ are contained in NCDOT's response to NCDWQ's comments.
The NCDOT cannot propose stream credits based on "draft Interim Stream Mitigation
Guidelines for the State of North Carolina" because it does not have a copy of this document. It-
is likely that the revised ratios for stream mitigation may include the benefits of upland buffers as
referenced in the EPA's August 6, 1999 letter.
NCDWQ Comment. The NCDWQ stated that their rules mandated (15A NCAC 2H .0506 h-4)
that a credit must have at least one acre of restoration. As such, ratios must be the greater of
EPA's or NCDWQ's.
NCDOT Response: The NCDOT will utilize Federal and State policies regarding mitigation
ratios to make a proposal on mitigation credits. However, NCDOT requests that the MBRT
provide guidance on whether these policies will be unified under the new guidance being
developed by the USACE and all MBRT agencies.
NCDOT Response: The NCDOT will comply with MBRT standards, pending review by the
USACE. Both the NCDWQ and EPA are requiring that, in no case, should the wetland
mitigation credit ratio be less than 1:1. The NCDOT agrees with this policy The EPA stated in
their June 13, 2001 letter that the MBRT agreed in a June 1 2000 meeting to use the following
mitigation ratios: 1:1 for restoration, 2:1 for enhancement. 3:1 for creation and 5:1 for
preservation. This procedure was outlined in Mr. David Lekson's June 27, 2000 letter. The
NCDOT agrees to these ratios.
Clayhill Farms Supplement
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Addendum 16
NCDWQ Comment: Each credit in a proposed mitigation bank must include a minimum of one
acre of restoration or creation (15A NCAC 2H .0506 h-4)
NCDOT Response: The EPA indicated that they are in agreement with North Carolina's Draft
Interim Stream Mitigation guidelines; however NCDOT has not had the opportunity to review
these draft guidelines.
The NCDWQ states in their guidance that "1:1. NCDWQ will consider other ratios in unusual
situations." The NCDOT requests that the NCDWQ elaborate on what was being considered
when the term "unusual situations" was referenced. NCDOT believes Priority 1 restoration
should be considered unique and thus unusual since it is restoring 1) pattern, 2) plan, 3) profile
and 4) reconnecting the stream to the pre-existing floodplain elevation, thus restoring natural
over bank flooding to adjoining wetlands. The NCDOT must always comply with the most
stringent of Federal and State policies, and therefore requests that the MBRT provide guidance
on whether the stream policy of the NCDWQ is consistent with the federal policies in this
regard. The NCDOT also wishes to learn whether all federal and state agencies have accepted
draft stream mitigation guidelines developed by the USACE with input from all MBRT agencies.
NOTE: SEE ALSO MITIGATION PLAN REPORT SECTION 7.0 OF THIS SAME
ADDENDUM FOR ADDITIONAL INFORMATION REGARDING WETLAND CREDITS.
Stream Compensation Ratios
NCDWQ Comment: The ratios must be consistent with greater of ratios specified by the
USACE/EPA and the NCDWQ. The NCDWQ Interim, Internal DWQ Policies on Stream
Mitigation Options and Associated Macrobenthos Monitoring memorandum (May 10, 2000)
states that the ratio for stream restoration is 1:1 and specifies a 50 foot wide buffer in the coastal
plain.
USACE Comment: The USACE's draft guidance (not released at the time of this meeting)
allows ratios less than 1:1 if complete restoration (pattern, plan and profile) is provided. Public
notice on this guidance is not expected until spring 2002. The intent of the Guidance is that
NCDWQ will also sign off on to the policies, but discrepancies regarding compensation ratios
has yet be resolved between agencies.
NCDOT Response to Both Comments: The NCDWQ guidance appears to allow some
flexibility given the statement in the guidance that the ratio for restoration is flexible, as noted in
under Section 2, "Stream Restoration" in this guidance which states "1:1. DWQ will consider
other ratios in unusual situations." We request the DWQ elaborate on what was being
considered when the term "unusual situations" was included. The NCDOT believes that
"Priority 1 Restoration" should be considered unique, and thus unusual, since proposed activities
Clayhill Farms Supplement
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Addendum 17
involve restoring pattern, plan, profile and reconnecting Billy's Branch to the pre-existing
floodplain elevation, thus eliminating the incision as it currently exists.
USACE Comment: The USACE requires a 1:1 stream restoration ratio in the Mitigation
Banking Instrument (MBI); lower ratios can be discussed on a permit-by-permit basis.
EPA Response: The EPA concurs with the USACE and will allow lower ratios on a permit-by-
permit basis.
NCDOT Response: NCDOT concurs
NCDOT Comment: ne N O requests a . .If am -reserva on o. ie o °er ra
,ccaunfs for the pPeservation of the entire Nvatersfi&
EPA Response: The EPA feels dais ratio Should be higher based of the"t review of tho Interim
t am-Mitigation Guidance fi?[ Nor Carolina!
3.9 Proposed Schedule for Bank Completion and Credit Release
The following credit release schedule is endorsed by the Division of Water Quality:
15%-contingent upon approval of the final mitigation plan, approval and signature of the MBI,
recordation of the conservation easement, and establishment of financial assurances,
10%-approval of 1" year monitoring report,
10%-approval of 2nd year monitoring report,
10%-approval of 3`d year monitoring report,
15%-approval of 41h year monitoring report,
10%-approval of 5`h year monitoring report,
25%-final approval by MBRT.
NCDOT Response: The NCDOT noted an error in credit release schedule endorsed by
NCDWQ as the percentages do not equal 100% but to 95%. It is assumed that an additional 5%
needs to be included the release schedule.
NCDOT Comment: The NCDOT concurs with the schedule proposed by the NCDWQ in the
January 10, 2002 letter to the USACE.
15%-contingent upon approval of the final mitigation plan, approval and signature of the MBI,
recordation of the conservation easement, and establishment of financial assurances,
10%-approval of I S` year monitoring report,
10%-approval of 2'd year monitoring report,
10%-approval of ) year monitoring report,
15%-approval of 4`h year monitoring report.
Clayhill Farms Supplement
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Addendum 18
15%-approval of 5`h year monitoring report,
25%-final approval by MBRT.
4.1 Proposed Service Area
Geographic Service Area (GSA)
EPA Comment: The EPA's letter of June 13, 2001 states that the "EPA recommends the
geographic service area (GSA) be limited to the 8 digit HUC portion of the White Oak River in
which the mitigation bank resides (03020106) consistent with the agreement made by the MBRT
agencies at our April 27, 1999 meeting. The use of the bank for projects outside of this 8-digit
HUC unit may be made on a permit-by-permit basis."
USACE Comment: The USACE agreed with the recommendation of the EPA.
NCDOT Response: The NCDOT will agree to this recommendation and will revise Section 4.1
of the Prospectus and Figure 3 "Service Area Map" in the Prospectus accordingly.
NCDWQ Comment: The Division approves of the proposed service area for the Clayhill Farms
Mitigation Bank.
NCDOT Response: The geographic service area (GSA) has been revised to the 8 digit HUC
portion of the White Oak River in which the mitigation bank resides (03020106) consistent with
the comments of the USEPA in their June 13, 2001 letter (and agreement made by the MBRT
agencies at a April 27, 1999 meeting). The EPA also stated, "use of the bank for projects outside
of this 8-digit HUC unit may be made on a permit-by-permit basis." The NCDOT endorses such
flexibility.
4.2 Monitoring
NCDWQ Comment: The Division concurs with the length of wetland monitoring, while the
stream monitoring should follow the guidelines in the Interim Internal Guidance for Stream
Work in North Carolina mentioned above.
NCDOT Response: The NCDOT proposed monitoring similar in nature to the reference
guidance in the Mitigation Banking Prospectus for Clayhill Farms Mitigation Bank. This
proposed monitoring for Clayhill Farms contains items similar to NCDWQ's Interim Internal
Guidance, except for surveying macrobenthos and fish as well as completing a habitat
assessment form.
Clayhill Farms Supplement
5/23/2002
Addendum 19
4.3.1 Wetland Hydrology
NCDWQ Comment: The Division's position on monitoring wetland hydrology is to compare
the restored site's annual hydroperiod to the reference wetland hydroperiod.
NCDOT Response: The NCDOT has not seen any guidance from the NCDWQ nor federal
agencies related to this newest hydrology success criteria. The NCDOT addresses this issue in
the response to comments received during the Prospectus meeting in October 2001.
Specifically, no clarification has been provided by the resource agencies on how to compare
reference data to on-site data regarding duration, proximity to the surface, average water depth,
nor acceptable variance regarding average depth or duration. Since there is not any written
standards, the NCDOT does not see how such a new standard can be arbitrarily applied. The
concept has been used at Croatan Mitigation Bank and NCDOT agreed to this concept on a test
basis. The NCDOT believes Croatan may be a test site for such an experiment along with the
on-going research grant provided to N.C. State University. Therefore, NCDOT does not agree to
using such criteria at Clayhill Farms Mitigation Bank.
NOTE: SEE ALSO MITIGATION PLAN REPORT SECTION 6.1 OF THIS SAME
ADDENDUM FOR ADDITIONAL INFORMATION REGARDING WETLAND CREDITS.
4.3.3 Stream Monitoring
NCDWQ Comment: The Division of Water Quality stream monitoring is referenced in the
Interim, Internal Technical Guide Summary-Benthic Macroinvertebrate Monitoring Protocols
for Compensatory Stream Restoration Projects, May 10, 2000; and the Internal Technical Guide
for Stream Work in North Carolina. In addition, the Division supports the Draft Stream
Mitigation Guidance as proposed by the US Army Corps of Engineers.
NCDOT Response: The NCDOT has not had the opportunity to review and analyze the Draft
Stream Mitigation Guidance as proposed by the USACE. The NCDOT wishes to discuss the
specifics of stream monitoring requirements with all agencies at the next MBRT meeting to
insure that the development of monitoring criteria are coordinated properly.
NCWRC Comment: The NCWRC would like the NCDOT to conduct biological monitoring of
fish and macrobenthics in an effort to compare pre- and post-construction conditions.
NCDOT Response: The NCDOT has considered this request. The NCDOT will perform
sampling of the stream pre-construction and then during monitoring years of 1, 3 and 5. This
data will not be used for any success criteria at the mitigation bank.
NCWRC Comment: The NCWRC would like stream mitigation to be comparative to stream
order mitigated. This will prevent the loss of aquatic habitat.
Clayhill Farms Supplement
5/23/2002
Addendum 20
USACE Response: Would like "stream mitigation to be comparative to stream order mitigated"
to be added to the addendum. The USACE agreed that Billy's Branch is a 2°d order stream.
NCDOT Response: The NCDOT concurs, although the condition of streams of higher order as
well as the type of impact should be evaluated to the ecosystem restoration provided at Clayhill
Farms. The use of Clayhill Farms to compensate for impacts to higher order streams should be
allowed on a case-by-case basis.
Clayhill Farms Supplement
5/23/2002
Addendum 21
N. C. DEPARTMENT OF TRANSPORTATION
TRANSMITTAL SLIP` DATE
TO: - REF. NO. OR ROOM, BLDG.

FROPM-N REF. NO. OR ROOM, BLDG.
t ??^? ((
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ACTION
?CNOTE AND FILE ? PER OUR CONVERSATION
?-NOTE AND RETURN TO ME ? PER YOUR REQUEST
11 RETURN WITH MORE DETAILS ? FOR YOUR APPROVAL
? NOTE AND SEE ME ABOUT THIS ? FOR YOUR. INFORMATION::.
- ? PLEASE. ANSWER -? FOR YOUR COMMENTS
? PREPARE REPLY FOR MY SIGNATURE•? SIGNATURE
? TAKE APPROPRIATE ACTION ? INVESTIGATE AND REPORT
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BILLY'S
BRANCH

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______________
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21
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RESTORATION -
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HEAD ATER SW P <I
'NON-RNERI
4tlEf HARDWO D
11 FOREST
o RgSTORATiO
flestaration = 144.200-
Headwater Swaap ... .... 39.4ao.
Non-riverine wet hardwood ..•. 45.Tac.
Mesic pine flotwoods .... 37 So
Mixed Mesic hardwood ... • . c.
Replanting - 12.400.
Mesic pine flotwooda .... ... .4.Bac.
Mixed Mesic hardwood •••••.•.7.6aa.
II --
Mesic pine flotwoods
Non-rIverI no wet hardwood forest
Headwater Swam? Forest Total acerage: 42.100.
Total acerage: 45.7ac. Total stems: _____
Total acerage: 39.4oc. Total stems: Longleaf I
t --
Total stems: _____ Swamp chestnut aok IOuarcus mtchauzii. FACW-I P ne nus alustrts. FACU+)
d ----- Pond Pine (Ptnus sera( lrw. FACW+) -----
ad, cypress ITaxodium distlchlm. OBLf _____ Laurel oak (Ouercus Iaurifallo. fACW) ___:_
Swamp blockgum (Nyasa sylvatica var. blflora. OBU _____ Cherrybark oak (guercus folccto var. pagodafolim FAC+) -----
Pond pine (Pink serotlno. FACW+) ____ Yellow-poplar (Lirlodendron tuI,Pifaro- FAC) -----
Yellow-poplar (Lirlodendran tulipifera? FAC) _____ American elm (Ulmis omerlcona. FACW) _____
Mixed meslc hardwood forest
flood Urplanted
Total acerage: 29.4oc.
Total stems:
Yellow-poplar (Liriodendron tulipifero. FAC)
Swamp chestnut oak (Ouercus miGwuxti. FACW-) _____
Cherrybark Oak (Ouercus fa Icata vor, pagodafalia. FAC+)
Laurel oak (Ouercus laurifolia. FACW) _____
American elm (Ulmrs a ericana. FACW) -----
WETLAND MITIGATION
PLANTING PLAN
SCALE:1'=300'
GRAPHIC SCALE 1'=300'
300 6 300 600 900
N
1
1

Shear Stress and Sediment Entrainment Analysis
(For gravel and cobble-bed streams)
To determine the ability of the existing (and proposed) stream reach to transport its
bedload it is necessary to calculate the critical dimensionless shear stress (i*ci)
needed to mobilize and transport the largest particle in motion under bankfull flow
conditions and conduct an entrainment analysis of the existing and proposed
channel.
1. BAR SAMPLE - Collect sediment core samples from point bars along the project
and reference reaches. At least one sample should be collected from each reach
associated with a change in stream type. Conduct a critical shear stress analysis
using the following procedures:
a) Locate a sampling point on the downstream one-third of a meander
bend. The sample location on the point bar is halfway between the
thalweg elevation (the point of maximum depth) and the bankfull stage
elevation. Scan the point bar in this area to determine the sampling
location by observing the maximum particles that are on the surface of
the bar.
b) Place the five-gallon bottomless bucket at the sampling location over
one of the representative maximum particles that was observed on the
lower one-third of the point bar. Remove the two largest particles from
the surface covered by the bottomless bucket. Measure the
intermediate axis for each particle and individually weigh the particles.
Record these values. The largest particle obtained is D;, the largest
particle from the bar sample. Push the bottomless bucket into the bar
material. Excavate the materials from the bottomless bucket to a depth
that is equal to twice the intermediate axis width of the largest surface
particle. Place these materials in a bucket or bag for sieving and
weighing.
c) For fine bar materials: Follow the directions above, except that when
the bottomless bucket is pushed into the bar material, excavate
materals from the bucket to a depth of 4 to 6 inches. Place these
materials in a bucket or bag for sieving and weighing.
d) Wet-sieve the collected bar materials, using water and a standard sieve
set with a 2-millimeter screen size for the bottom sieve. Weigh bucket
with sand after draining off as much water as possible. Subtract tare
weight of bucket to obtain the net weight of the sand.
e) Weigh materials sieved and record weights (less tare weight) by size
class. Be sure to include the intermediate axis measurements
Procedures from Dave Rosgen-River Assessment and Monitoring 3003 (AGO 41812(XV)
Sheet 1 of 5
and individual weights of the two largest particles that were
collected.
f) Determine a material size class distribution for all of the collected
materials. The data represents the range of channel materials subject
to movement or transport as bedload sediment materials at bankfull
discharge.
g) Plot data; determine size-class indices, i.e., D16, D35, Dso, D84, D95. The
Dioo should represent the actual intermediate axis width and weight
(not the tray size) when plotted. The largest size measured will be
plotted at the Dloo point. (Note: Dioo = Di). The intermediate axis
measurement of the second largest particle will be the top end of the
catch range for the last sieve that retains material.
h) Survey a typical cross section of a riffle reach at a location where the
stream is free to adjust its boundaries. Plot the survey data.
Determine the hydraulic radius of the cross-section.
i) Conduct a Wolman Pebble Count (100 count in riffle) of the bed
material in the coarsest portion of the wetted riffle area. The pebble
count should be conducted at multiple transects that represent the
riffle. Plot data and determine the size-class indices.
2. PAVEMENT/SUBPAVEMENT SAMPLE - Alternate procedures for
obtaining a pavement/subpavement sample when you are unable to
collect a bar sample:
a) Locate a sampling point in the same riffle where cross-section survey
was conducted. The sampling point should be to the left or right of the
thalweg, not in the thalweg, in the coarsest part of the riffle.
b) Push the five-gallon bottomless bucket into the riffle at the sampling
location. Be sure to push the bucket into the riffle so that the flow is
cut off to the area inside the bucket.
c) Remove the pavement material (surface layer onlx) by removing the
smallest to the coarsest particles. Measure the intermediate axis and
weight of the largest and second largest particles. Record these
values. Place the remaining pavement materials into a bucket or bag
for sieving and weighing.
d) Remove the subpavement material to a depth that is equal to twice the
intermediate axis width of the largest particle in the pavement layer.
Caution: If you get to a coarser bed material under the
subpavement that is pavement material remnant of the
previous bed, stop immediately even if you are not at twice the
ProeedUres from Dave Rosgen-River Assessment and )Oonit.oring 2002 GAGJ 41812002)
Sheet 2 of 5
maximum pavement particle depth. This residual layer is not
available to be transported at bankfull flow.
e) Collect the subpavement materials into a separate bucket or a bag.
Measure the intermediate axis and weight of the two largest particles in
the subpavement sample. Record these values. Sieve and weigh the
remaining subpavement materials. The subpavement sample is the
equivalent of the bar sample; therefore, you use the largest particle
from the subpavement sample in lieu of the largest particle from a bar
sample in the entrainment calculations. Note: If you collect larger
particles from the subpavement than you did from the
pavement layer, do not use these big rocks to determine the
largest particle in the subpavement layer. Drop back to the
next largest particle group to determine the largest particle
size to be used in entrainment calculations.
j) Wet-sieve the collected pavement materials and then the subpavement
materials, using water and a standard sieve set with a 2-millimeter
screen size for the bottom sieve. Weigh bucket with sand after
draining off as much water as possible. Subtract tare weight of bucket
to obtain the net weight of the sand.
k) Weigh materials sieved and record weights (less tare weight) by size
class for both the pavement and subpavement samples. Be sure to
include the mean intermediate axis width and individual net
weights of the two largest particles that were collected.
1) Determine a material size class distribution for the materials. The
subpavement data represents the range of channel materials subject to
movement or transport as bedload sediment materials at bankfull
discharge.
m) Plot data; determine size-class indices, i.e., D16, D35, D50, D84, D95. The
Dioo should represent the actual intermediate axis width and weight
(not the tray size) when plotted. The largest size measured will be
plotted at the D100 point. (Note: D100 = Di). The intermediate axis
measurement of the second largest particle will be the top end of the
catch range for the last sieve that retains material.
n) The pavement material size class distribution may be used to determine
the D50 of the riffle bed instead of doing the 100 count in the riffle bed.
3. Determine the existing average bankfull slope (approximated by the
average water surface slope) for the study reach from the longitudinal
profile.
Procedures from Hive Rower-River Assessnie:;ni and Nl ni€oriry '2002 (AG7 4/8/2002)
Sheet 3 of 5
4. Using the following equations, determine the critical dimensionless shear
stress required to mobilize and transport the largest particle from the bar
sample (or subpavement sample).
a) Calculate the ratio D5o/D50
Where: D50 = median diameter of the riffle bed (from 100 count
in the riffle or pavement sample)
A
D50 = median diameter of the bar sample (or
subpavement sample)
If the ratio D50/D50 is between the values of 3.0 and 7.0, then
calculate the critical dimensionless shear stress using Equation 1.
ci = (Equation 1)
i* 0.0834 (D5o/D5o)-0'$7Z
b) If the ratio D50/D50 is not between the values of 3.0 and 7.0, then
calculate the ratio of D;/D50
Where: Di = Largest particle from the bar sample (or the
subpavement sample)
D50 = median diameter of the riffle bed (from 100 count
in the riffle or the pavement sample)
If the ratio D;/D5o is between the values of 1.3 and 3.0, then
calculate the critical dimensionless shear stress using Equation 2.
i*d = 0.0384 (D;/D50)-0'$$' (Equation 2)
5. Once the critical dimensionless shear stress is determined, the minimum
bankfull mean depth required for entrainment of the largest particle in the
bar sample (or subpavement sample) and the bankfull water surface slope
required for entrainment of the largest particle can be calculated using
Equation 3 and 4.
dr = 1.651 Se
Sr = 1.651 de
(Equation 3)
(Equation 4)
procedllrr, trom Dave Rosgen-.River Assessment and Mo?rlit(WiTlg 2002
(AG)J 41812002)
Sheet 4 of 5
Where: dr (ft) = Required bankfull mean depth
de (ft)= Existing bankfull mean depth
1.65 = Sediment density (submerged specific weight)
= density of sediment (2.65) - density of water (1.0)
*c; = Critical dimensionless shear stress
D; (ft) = Largest particle from bar sample (or
subpavement sample)
Sr (ft/ft) = Required bankfull water surface slope
se (ft/ft) = Existing bankfull water surface slope
6. Double check sediment competence by calculating bankfull shear stress
using Equation 5.
i = yRS
(Equation 5)
Where: ti = Bankfull shear stress, lbs./ft.2
y = Specific weight of water = 62.4 lbs./cu. ft.
R = Hydraulic radius of riffle cross section, ft.
s = Average water surface slope, ft./ft.
Use the calculated value of ti (lbs./ft2) and the Shield Diagram with
Colorado data (Figure 7) to predict the moveable particle size (mm) at
bankfull shear stress.
Use the value of the largest particle in the bar sample (or subpavement
sample),D;, in millimeters and the Shield Diagram with Colorado data
(Figure 7) to predict the shear stress required to initiate movement of Di.
Procedures from Dave klosgen-River Assessment and Monitoring 2002 (AGJ 41812002)
Sheet 5 of 5
DEPARTMENT OF THE ARMY
WILMINGTON DISTRICT, CORPS OF ENGINEERS
P.O. BOX 1890
WILMINGTON, NORTH CAROLINA 28402-1890
IN REPLY REFER TO September 18, 2001
Regulatory Division
Action ID No. 200100746, Clayhill Farms Mitigation Bank
See Distribution
Dear Colleague:
This correspondence is in reference to the Clayhill Farms Mitigation Bank that is being
developed by the North Carolina Department of Transportation (NCDOT), located in Jones
County, North Carolina. Also, reference the final mitigation plan for this Bank dated July 1999.
As a member of the Mitigation Bank Review Team (MBRT), you are invited to attend a
meeting on Wednesday, October 24, 2001 at the Clayhill Farms Mitigation Site located on NC 58
in Jones County, North Carolina (map enclosed). Please meet at the intersection of NC 58 and
SR 1100 at 10:00 am. The purpose of the meeting is to discuss the Clayhill Farms Mitigation
Bank Prospectus, inspect the mitigation site, review the sixty-percent design plans, and address
any questions regarding the technical details of this proposal. Please review the final mitigation
plan and prospectus for this Bank prior to this meeting. Should you need additional copies of
these documents please advise.
Thank you for your time and cooperation. If you have any questions, please contact
Mr. Dave Timpy, Wilmington Regulatory Field Office, telephone [phone].
Sincerely,
E. David Franklin
NCDOT Team Leader
Distribution (with enclosure):
Mrs. Kathy Matthews
U.S. Environmental Protection Agency
980 College Station Road
Athens, Georgia 30605
RECEIVED
SAP 24 2001
NC WETLANDS
RESTORATION

Mr. Tom McCartney
U.S. Fish and Wildlife Service
Fish and Wildlife Enhancement
Post Office Box 33726
Raleigh, North Carolina 27636-3726
Mrs. Kelly Williams
Division of Coastal Management
North Carolina Department of Environment,
Health, and Natural Resources
Post Office Box 27687
Raleigh, North Carolina 28557-7687
Mr. Bennett Wynne
NC Wildlife Resources Commission
901 Laroque Avenue
Kinston, NC 28501
Mr. Mac Haupt
North Carolina Wetland Restoration Program
1619 Mail Service Center
Raleigh, NC 27699-1619
Mr. Phillip Todd
Project Development & Environmental
Analysis Branch
NC Department of Transportation
1548 Mail Service Center
Raleigh, N.C. 27699-1548
Mr. John Dorney
NCDENR-DWQ
Wetlands Section
1621 Mail Service Center
Raleigh, NC 27699-1621
2
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Revisions to the Planning Document for Clayhill Farms Mitigation Site
Page 30, Section 5.2, 3rd Paragraph, 1St Sentence.
Areas disturbed by hydrologic restoration will be seeded with a mix appropriate for
wetland areas.
Page 31, Section 6.0.
The stream restoration area will be monitored for one year.
Page 32, Section 6.2
Vegetation and channel/stream bank stability will be monitored for the stream restoration
portion of the site for one year. The NCDOT will visually monitor vegetation plantings
and ensure stabilization of the channel/stream bank. Quarterly visits will be made to the
site to visually monitor the mitigation area with photographs taken to demonstrate the
progress and stability of the mitigation work.
Page 32, Section 6.4, 2nd Paragraph.
The NCDOT will take representative photographs of the mitigation site. The last
sentence of the mitigation planning document in this paragraph should be stricken.
0
FINAL
WETLAND & STREAM MITIGATION PLAN REPORT
for the

NCDOT Consulting Project No. 98-LM-03 & 96-LM-19
State Project No. 6.16900IT
TIP No. R-2105
L&M Project No. 1960024-203.00 & 1960024-019.00

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4. 1
40
CLAYHILL FARMS PROPERTY
JONES COUNTY, NORTH CAROLINA
Prepared for the
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North Carolina
Ze South Wilmington Street, Post Office Box 25201
Raleigh, North Carolina 27611
Attn: Phillip Todd, Environmental Specialist, ,
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Issued: July 1999
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TABLE OF CONTENTS
LIST OF TABLES ................................................................................................................................... iv
LIST OF FIGURES ................................................................................................................................. iv
1.0 EXECUTIVE SUMMARY ............................................................................................................... ..1
2.0 INTRODUCTION ............................................................................................................................. ..2
3.0 EXISTING AND HISTORIC CONDITIONS ................................................................................... ..2
3.1 Physiography .................................................................................................................................. ..2
3.2 Land Use History ........................................................................................................................... ..3
3.3 Soils ................................................................................................................................................ ..3
3.3.1 General Soil Boundaries ......................................................................................................... ..3
3.3.2 Hydric Soil Boundaries ........................................................................................................... ..5
3.4 Groundwater Hydrology ................................................................................................................ ..5
3.4.1 DRAINMOD Groundwater Monitoring Wells ....................................................................... ..5
3.4.2 Remote Shallow Groundwater Monitoring Wells .................................................................. ..5
3.4.3 DRAINMOD ........................................................................................................................... ..6
3.5 Surfacewater Hydrology ................................................................................................................ ..8
3.5.1 Development of Hydraulic Geometry Relationships (Regional Curves) ................................ ..8
3.5.2 Geomorphological Description of the Reference Reaches ..................................................... ..9
3.5.3 Morphological Analysis of Billy's Branch ............................................................................. 10
3.5.4 Hydrology and Hydraulics of Billy's Branch and Feeder Ditches ......................................... 11
3.6 Plant Communities ......................................................................................................................... 15
3.6.1 Pine Dominated Communities ................................................................................................ 15
3.6.2 Hardwood Dominated Communities ...................................................................................... 15
3.6.3 Recent Clearcuts and Open Areas ........................................................................................... 16
3.6.4. Protected Species and Ecologically Significant Communities .............................................. 16
3.7 Wetlands ........................................................................................................................................ 16
3.8 Wildlife .......................................................................................................................................... 17
3.8.1 Commonly Observed Species ................................................................................................. 17
3.8.2 Protected Species .................................................................................................................... 17
4.0 PROPOSED CONDITIONS .............................................................................................................. 19
4.1 Hydrology Modifications ............................................................................................................... 19
4. 1.1 DRAINMOD Results .............................................................................................................. 19
4.1.2 Proposed Cross-Sections and Geometry of Billy's Branch .................................................... 21
4.1.3 Proposed Alignment of Billy's Branch ................................................................................... 21
4.1.4 Proposed Hydraulics ............................................................................................................... 23
4.1.5 Floodplain Restoration ............................................................................................................ 25
4.2 Conceptual Planting Plan ............................................................................................................... 26
4.2.1 Reference Stands ...................................................................................................................... 26
4.2.2 Proposed Communities ........................................................................................................... 27
5.0 SITE CONSTRUCTION AND PLANTING REQUIREMENTS ..................................................... 29
5.1 Site Construction ............................................................................................................................ 29
NCDOT Clayhill Farms Wetland and Stream Mitigation Plan Report July 1999
Langley and McDonald, P. C., Nos. 1960024-203.00 and 1960024-019.00 Page ii
5.2 Site Preparation and Planting Requirements ..................................................................................30
6.0 SUCCESS CRITERIA .......................................................................................................................30
6.0 MONITORING PLAN ......................................................................................................................31
6.1 Wetland Mitigation Monitoring .....................................................................................................31
6.2 Stream Restoration Monitoring ......................................................................................................32
6.4 Reporting ........................................................................................................................................32
7.0 MITIGATION RATIOS ....................................................................................................................32
8.0 DISPENSATION OF PROPERTY ...................................................................................................33
9.0 CONCLUSIONS ................................................................................................................................33
10.0 REFERENCES CITED ....................................................................................................................35
APPENDICES
Appendix A. Soil Boring Logs
Appendix B. NRCS Prior-Converted Cropland Determination
Appendix C. DRAINMOD Technical Appendix
Appendix D. Surfacewater Hydrology Technical Appendix
Appendix E. Species Lists
NCDOT Clayhill Farms Wetland and Stream Mitigation Plan Report July 1999
Langley and McDonald, P. C., Nos. 1960024-203.00 and 1960024-019.00 Page iii
LIST OF TABLES
Table 1. DRAINMOD monitoring well water table measurements (February 11, 1999) ........................ 6
Table 2. Existing conditions of feeder ditches ........................................................................................13
Table 3. Peak flow rates of each drainage area .......................................................................................13
Table 4. Existing surface water profile of Billy's Branch ......................................................................14
Table 5. Pre and post-restoration DRA , MOD field simulations for the 40-year modeling period ....... 20
Table 6. Sensitivity model for assessing DRAINMOD saturation and ponding results ......................... 21
Table 7. Proposed conditions of feeder ditches ...................................................................................... 24
Table 8. Proposed surface water profile of Billy's Branch ..................................................................... 25
Table 9. Existing and proposed peak flood elevations ............................................................................ 26
Table 10. Mean community characteristics for vegetation sample plots ................................................ 27
Table 11 . Compensatory mitigation provided by the Clayhill Farms property ...................................... 34
LIST OF FIGURES
(Figure follows page listed)
Figure 1. Vicinity Ma 2
Figure 2. General Site Map ..............................................................................................:....................... 3
Figure 3. Soils Map .................................................................................................................................. 3
Figure 4. Groundwater Flow Map ............................................................................................................ 5
Figure 5. DRAINMOD Existing Conditions ........................................................................................... 8
Figure 6. Reference Reach Characteristics .............................................................................................. 9
Figure 7. Drainage Area, Nodes & Proposed Channel Characteristics .............................
Figure 8. Existing and Proposed Cross-Sections ...................................................................................10
Figure 9. Drainage Areas of Billy's Branch ..........................................................................................11
Figure 10. Wetland Delineation Map .....................................................................................................17
Figure 11. DRAINMOD Proposed Conditions ......................................................................................19
Figure 12. Existing and Proposed Stream Plan View & Details ............................................................ 20
Figure 13. Proposed Stream Course Alignment & Corresponding Bankfull Shear Stress .................... 23
Figure 14. Landscape Profile of Natural Communities ......................................................................... 28
Figure 15. Proposed Planting Plan ......................................................................................................... 28
NCDOT Clayhill Farms Wetland and Stream Mitigation Plan Report July 1999
Langley and McDonald, P.C., Nos. 1960024-203.00 and 1960024-019.00 Page iv
1.0 EXECUTIVE SUMMARY
The North Carolina Department of Transportation (NCDOT) acquired the 355.60 acre Clayhill Farms
property in the summer of 1998 based upon the findings of the Wetland Mitigation Site Feasibility
Study conducted by Langley and McDonald in the fall of 1997 (L&M 1998). The following report
describes Clayhill Farms in detail and proposes methods for restoring, enhancing and preserving
wetland and non-wetland communities to compensate for wetland impacts associated with future road
construction projects. The Clayhill Farms property also provides the NCDOT with the opportunity to
restore 7,410 linear feet of stream which was channelized to maximize agricultural production in the
mid 1970's.
The following major studies were conducted on the property for the preparation of this report:
• Soils delineation and location by GPS survey on certain farm fields,
• Wetland delineation and location by traditional survey of forested lands mapped as
containing hydric soils,
• Groundwater table characterization and modeling using DRAINMOD,
• Shallow groundwater monitoring,
• Surface water hydrology and hydraulics of farm field (feeder) ditches,
• Fluvial geomorphological analysis of the channelized stream Billy's Branch,
• Surface water hydrology and hydraulics of Billy's Branch,
• Importance value calculations for reference habitats off-site,
• General inventory of vegetation and wildlife on-site, and
• Biological Conclusion of "Unresolved" for the red-cockaded woodpecker.
This report also addresses vegetation and stream monitoring protocol, mitigation ratios, and
dispensation of the property.
The 355.60 acre Clayhill Farms property currently contains approximately 155.9 acres of forested
wetlands and 199.7 acres of non-wetlands (141.8 acres of Prior Converted cropland and 57.9 acres of
forested land). The proposed wetland mitigation plan provides for 97.7 acres of wetland restoration,
1.8 acres of wetland enhancement, 155.9 acres of wetland preservation, 44.1 acres of upland
restoration, and 57.9 acres of upland preservation (Table 11, page 34). If the proposed mitigation ratios
are accepted, Clayhill Farms can provide mitigation for 71.6 acres of wetland impacts.
The Clayhill Farms property also contains 6,170 linear feet of incised, straightened stream. The
proposed restoration plan will restore 7,410 linear feet of stream. This will be done utilizing priority
one methodologies, which calls for re-establishing the stream at an elevation which is compatible with
the abandoned floodplain. By doing so, the stream mitigation plan causes approximately 65 acres of
floodplain to be re-established on-site by decreasing the width and depth of Billy's Branch and
increasing the sinuosity (decreasing the slope) of the stream.
NCDOT Clayhill Farms Wetland and Stream Mitigation Plan Report July 1999
Langley and McDonald, P. C, Nos. 1960024-203.00 and 1960024-019.00 Page I
Hydraulic analysis indicates that there should be no adverse affect of this stream restoration on
downstream properties. Current findings suggest that a berm (one foot high) may be needed along the
western boundary of the farm fields of the Clayhill Farms property to insure that the Croatan National
Forest property is not flooded. It appears the floodplain historically extended onto the lands of the
National Forest. For these reasons the NCDOT will request permission from representatives of the
National Forest to re-establish the historic floodplain off-site to that within the Clayhill Farms property.
If this cannot be achieved, the berm will be constructed.
2.0 INTRODUCTION
The North Carolina Department of Transportation (NCDOT) first became aware of Clayhill Farms in
early 1997 when the property was identified during the Langley and McDonald "Highway 24 Wetland
Mitigation Site Search" (NCDOT Consulting Project Number 96-LM-06, State Project Number
6.169001T). After determining that the owners of Clayhill Farms were willing to negotiate sale of the
property to the NCDOT, Langley and McDonald performed a Wetland Mitigation Site Feasibility
Study of the property in the fall of 1997 (96-LM-11, State Project Number 6.169001T). The NCDOT
purchased the property in the summer of 1998. The following report describes Clayhill Farms in detail
and proposes methods for restoring and preserving the natural communities there to provide
compensatory mitigation for wetland and stream impacts associated with future road construction
proj ects.
3.0 EXISTING AND HISTORIC CONDITIONS
The Clayhill Farms Wetland Mitigation Site (NCDOT Site No. WOKCU0219022, L&M Site Nos. JO-
6 and JO-7) is two adjacent parcels of land totaling 355.60 acres (Jones County Tax Parcels 5369-20-
8859-00 and 5369-40-3101-00). Clayhill Farms is located in southwestern Jones County, North
Carolina on the Hadnot Creek, NC and Stella, NC 7.5" U.S.G.S. Topographic Quadrangles (Figure 1,
Vicinity Map). It is bordered to the north, east and west by the Croatan National Forest and to the
south and east by various forested and residential parcels. It is bisected by Billy's Branch, a tributary
to Hunters Creek.
3.1 Physiography
Clayhill Farms is located in the Atlantic Coastal Plain Physiographic Province of North Carolina. This
area is comprised of sediments that were deposited during transgressive-regressive cycles caused by
worldwide sea level fluctuations. In part, these fluctuations were the result of the expansion and
recession of glacial ice caps. During interglacial periods, relatively high sea levels allowed for
deposition of marine and shoreline sediments. Conversely, during glaciation, the falling sea level
caused regression and eventual downcutting by streams and rivers (Soller and Mills 1991).
Based upon the Geologic Map of North Carolina (1985), the surficial sediments at Clayhill Farms are
comprised of the Duplin Formation. The Duplin Formation consists of bluish gray, shelly, medium-to
NCDOT Clayhill Farms Wetland and Stream Mitigation Plan Report July 1999
Langley and McDonald, P. C, Nos. 1960024-203.00 and 1960024-019.00 Page 2
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Wetland & Stream Mitigation
Plan Report
Figure 1
Vicinity Map
Legend
-- Subject Property
- - - On-site Reference Reach
-••-••• Off-site Reference Reach
Vegetation Reference
Areal
Vegetation Reference
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coarse-grained sand, sandy marl, and limestone. In cross-section, the site and vicinity are characterized
by relatively flat lying sediments that gently fall to the southeast. Elevations on the site range from
approximately 20 to 36 feet above sea level (Figure 2, General Site Map).
3.2 Land Use History
Clayhill Farms was logged in the early 1970s and portions of it were converted to agriculture. At that
time, perimeter ditches and farm drainage ditches were excavated and Billy's Branch was channelized.
Drainage ditches in the western (poorly drained) farm fields were excavated 250 to 450 feet apart.
Drainage ditches in the more well drained eastern half of the property were placed at the bottom of
topographic gradients within former drainage swales and stream channels. These ditches range from
600 to 1,700 feet apart.
The approximately 141.8 acres of Clayhill Farms put into agricultural production in the 1970s was
continuously farmed by Mr. Earl Jones and his family until the sale of the property to the North
Carolina Department of Transportation in 1998. The 213.8 acres of the property that are presently
forested contain a mosaic of disturbed and natural communities. Of this 213.8 acres, approximately
19.0 acres (all hardwood dominated forest) appear not to have been harvested in the 1970s. The
remaining 194.8 acres appears to have been clearcut in the 1970s and allowed to regenerate naturally
into a mixed community of loblolly pine (Pinus taeda) and pond pine (Pinus serotina). Approximately
44 acres of pine forest on the western half of the property have been thinned in the past five years; the
remaining forest has not been cut. Approximately 11.7 acres of forest were again clear-cut in early
1998 and have not been replanted.
3.3 Soils
3.3.1 General Soil Boundaries
On February 1 through 3, 1999, Langley and McDonald supervised the completion of 20 soil borings
throughout the site in order to describe the site soils/sediments and to facilitate aquifer permeability
tests as described in Section 3.4.3. The soil borings were installed with an all terrain vehicle mounted
drill rig. The borings were performed with 4.25-inch (inside diameter) hollow stem augers and
continuous split spoon sampling from the surface to approximately 15 feet below ground surface (bgs).
The Soil Survey of Jones County, North Carolina (USDA 1981) identifies five soil types within the
site, all of which are mineral soils. Soils samples were analyzed in the field for texture and color and
were found to be as generally described in the soil survey. (Detailed soil boring logs are included as
Appendix A.) As is expected, however, the soil series boundaries depicted in the soil survey are
general, and the actual soil series boundaries were found to vary some from those published. General
soil boundaries and boring locations (indicated by the presence of DRAINMOD wells) are depicted on
Figure 3. Figure 3 also illustrates where soils sampled for borings were determined to contradict soil
survey mapping.
NCDOT Clayhill Farms Wetland and Stream Mitigation Plan Report July 1999
Langley and McDonald, P. C., Nos. 1960024-203.00 and 1960024-019.00 Page 3
Clayhill Farms
Wetland & Stream Mitigation
Plan Report
Figure 2
General Site Map
Legend
Property Boundary
Centerline of Stream
-°-••- Manmade Ditch
Road
Culvert
Pine Dominated Forest
Recently Clearcut Forest
- Hardwood Dominated
Forest
Groundwater Monitoring
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DRAINMOD Well
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Project #1960024-203. 00 & 1960024-019.00
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Clayhill Farms
Wetland & Stream Mitigation
Plan Report
Figure 3
Soils Map
Legend
Property Boundary
Centerline of Stream
-••-••- Manmade Ditch
Road
Culvert
DRAINMOD Well
(Soil Boring)
General Soil Type Boundaries
(From Soil Survey)
Non-Hydric Soils
Approximated from Sampling
Non-Hydric Soils
III 11!1 G Approximated from Wetland
Delineation
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The five soils confirmed to occur on the Clayhill Farms property are listed and described as follows (in
decreasing order of extent):
1. Onslow fine sandy loam (On) - Spodic Paleudult: A nearly level, moderately well drained
soil in interstream areas near drainageways. Typically, the surface layer is dark gray fine
sandy loam 9 inches thick. The subsurface layer is pale brown loamy fine sand 6 inches
thick. It has an intermittent thin hardpan. The subsoil is 61 inches thick. It is light olive
brown and pale brown sandy clay loam in the upper part and gray and light brownish gray
sandy loam in the lower part. The underlying material to a depth of 80 inches is light
brownish gray sandy clay loam. The seasonal high water table is at a depth of 1.5 to 3.0
feet. It is not listed as a hydric soil in the 3`a Edition of Hydric Soils of the United States
(USDA 1991).
2. Torhunta fine sandy loam (To) - Typic Humaquept: A nearly level, very poorly drained
soil in broad interstream areas and in depressions near shallow drainageways. Typically, the
surface layer is fine sandy loam 15 inches thick. It is black in the upper part and very dark
gray in the lower part. The subsoil is 32 inches thick. It is dark gray fine sandy loam in the
upper part and grayish brown sandy loam in the lower part. The underlying material to a
depth of 72 inches is light brownish gray stratified loamy sand, sandy loam, and sand. The
seasonal high water table is at a depth of 0.5 to 1.5 feet from December to May. It is listed
as a hydric soil.
3. Pantego loam (Pn) - Umbric Paleaquult: A nearly level, very poorly drained soil on broad,
smooth flats in interstream areas. Typically, the surface layer is black and very dark gray
loam 15 inches thick. The subsoil is 53 inches thick. It is grayish brown sandy clay loam in
the upper and middle parts and gray sandy clay loam in the lower part. The underlying
material to a depth of 80 inches is greenish gray sandy clay loam. The seasonal high water
table is at the surface or to a depth of 1.5 feet from December to May. It is listed as a hydric
soil.
4. Marvyn loamy sand, 6 to 15 percent slopes (MaQ - Typic Hapludult: A well drained soil
on side slopes near major drainageways. Typically, the surface layer is dark grayish brown
loamy sand three inches thick. The subsurface layer is light yellowish brown loamy sand 14
inches thick. The subsoil is strong brown sandy clay loam 31 inches thick. The underlying
material to a depth of 70 inches is reddish yellow sandy loam and yellow loamy sand. The
seasonal high water table is below a depth of about 6 feet. It is not listed as a hydric soil.
5. Muckalee loam (Mk) - Typic Haplaquod: A nearly level, poorly drained soil in
drainageways. Typically, the surface layer is dark grayish brown loam and dark gray sandy
loam 24 inches thick. The underlying material to a depth of 65 inches is mottled gray and
grayish brown sand and greenish gray loamy sand. The seasonal high water table is at depth
of 0.5 to 1.5 feet. It is listed as a hydric soil.
NCDOT Clayhill Farms Wetland and Stream Mitigation Plan Report July 1999
Langley and McDonald, P.C., Nos. 1960024-203.00 and 1960024-019.00 Page 4
3.3.2 Hydric Soil Boundaries
The USDA Natural Resources Conservation Service (MRCS) performed a Prior-Converted (PC)
Cropland Determination of Clayhill Farms on July 19, 1990 (Appendix B). The fields have been in
continuous cultivation from the mid-1970s to 1998. All of the fields mapped as containing significant
amounts of Torhunta or Pantego were determined to be PC fields; the others were not. Sampling
performed during the feasibility study of this property (L&M 1997) revealed that much of the area
mapped as Onslow soil, and therefore considered to be non-hydric soil, was actually hydric soil.
In order to determine the location of hydric and non-hydric soils in the eastern farm fields more
accurately, soil samples were taken on a 100-foot grid with a two-inch diameter Dutch-style auger to a
depth of 24 inches and located by survey using a global positioning system (GPS). If the soil sample
collected met any one of the NRCS field indicators of hydric soils (USDA 1995), that sample was
recorded as hydric. Of the 272 samples collected, only 34.1 percent (93) were determined to be non-
hydric. Based on these samples, non-hydric soils within the farm fields were approximated as shown
on Figure 3. Approximately 120.5 acres of the farm fields are on hydric soil and 21.3 acres are on non-
hydric soil.
3.4 Groundwater Hydrology
3 4 1 DRAINMOD Groundwater Monitoring Wells
Subsequent to the soil boring activities, each boring was converted into a groundwater monitoring well
for use in DRAiNMOD (denoted as DMW on figures). The wells were constructed with two-inch
polyvinyl chloride (PVC) slotted casing from 14 feet bgs to 1.5 feet bgs. Attached to the slotted well
casing was a solid section of pipe (riser) from 1.5 feet bgs to approximate 2.5 feet aboveground surface.
The annular space was filled with filter sand from 15 feet bgs to 0.5 feet bgs and then the balance was
completed with bentonite pellets to the surface (See boring logs for well construction details).
The wells were allowed to equilibrate for a period of approximately one-week before they were gauged
with an electronic meter on February 17 and 18, 1999. Measurements were recorded to the nearest 0.01
foot and are listed in Table 1. Groundwater elevations ranged from 34.37 feet msl to 19.41 feet msl.
These water table elevations were extrapolated to produce the groundwater flow map included as
Figure 4. As depicted on the map, groundwater at the site is generally directed toward Billy's Branch
and somewhat mimics the topography of the site.
3 4 2 Remote Shallow Groundwater Monitoring Wells
Remote shallow groundwater monitoring wells were also installed on the site to take continuous
readings of the groundwater table (denoted as GW on figures). These wells are manufactured and sold
by Remote Data Systems, Inc. and extend 20 inches below the soil surface. The wells are programmed
to read the groundwater table once a day. The wells are downloaded once a month but can store data
for over a year as long as the batteries do not run down.
NCDOT Clayhill Farms Wetland and Stream Mitigation Plan Report July 1999
Langley and McDonald, P. C., Nos. 1960024-203.00 and 1960024-019.00 Page 5
Clayhill Farms
Wetland & Stream Mitigation
Plan Report
Figure 4
Groundwater Flow
Map
Legend
Property Boundary
Centerline of Stream
- --••--- Manmade Ditch
Road
Culvert
Forested Area
Recently Clearcut Area
Groundwater Monitoring
Well
DRAINMOD Well
Groundwater Contour
(in feet)
Groundwater Flow
Direction
I P
NORTH
1 "=500'
0 500 1000
NORTH CAROLINA
DEPARTMENT OF TRANSPORTATION
PROJECT DEVELOPMENT AND
ENVIRONMENTAL ANALYSIS BRANCH
Langley and McDonald, P.C.
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Project #1960024-203.00 & 1960024-019.00
The wells were installed prior to the beginning of the growing season and all but two (GW 17 and 18)
have functioned properly since the beginning of the growing season. As would be expected in a poorly
drained soil which has been ditched, the water table is erratic. It drops below 12 inches bgs and
remains there until a rain event. Following the rain event, the groundwater table recharges, often to the
surface, and remains above 12 inches for 7 to 10 days before falling below 12 inches again. At no well
has the groundwater table remained within 12 inches of the soil surface for five percent or more of the
growing season. As such, none of these sites met the wetland hydrology criterion as detailed in the
Corps of Engineers Wetland Delineation Manual (1987). Neither well in the Marvyn soil has recorded
a water level less than 20 inches from the surface any day since the wells were installed (prior to the
beginning of the growing season) on February 19, 1999.
It should be noted that while rainfall was average for the three months, 6 months, and 12 months
preceding the growing season (within 25 percent of mean precipitation), rainfall during the first two
months of the growing season was abnormally low (68 percent of normal in March 1999 and 55 percent
of normal in April 1999).
Table 1. DRAINMOD monitoring well water table measurements (February 11, 1999).
Soil Type Well Number Depth to Water Table from Ground
Surface (inches)
DMW-2 19.20
Onslow DMW-3 17.76
DMW-18 41.76
DMW-20 38.04
DMW-5 26.50
DMW-6 34.32
Torhunta DMW-7 26.76
DMW-8 3.24
DMW-19 20.40
DMW-1 17.52
DMW-4 18.48
Pantego DMW-15 35.76
DMW-16 23.52
DMW-17 18.12
DMW-9 104.52
DMW-10 100.80
Marvyn DMW-11 76.56
DMW-13 24.24
DMW-14 46.68
Muckalee DMW-12 44.88
3.4.3 DRAINMOD
DRAINMOD is a Fortran based computer model that simulates the performance of drainage, sub-
irrigation, and controlled drainage systems. The model was developed at North Carolina State
NCDOT Clayhill Farms Wetland and Stream Mitigation Plan Report July 1999
Langley and McDonald, P. C., Nos. 1960024-203.00 and 1960024-019.00 Page 6
University in the Department of Biological and Agricultural Engineering for application to agricultural
drainage and water table management systems. The basic assumptions/requirements for DRAINMOD
are (1) the modeled areas are field-sized units with parallel ditches, (2) the region has a humid climate,
and (3) the area has a shallow, unconfined aquifer.
DRAINMOD was adapted to wetland studies by including a subroutine calculation that accounts for
the wetland hydrology (i.e., the number of consecutive days the water table is less than 12 inches from
the ground surface during the growing season). For the purposes of this plan, DRAINMOD was used
in the "wetland hydrology mode" to:
1) Simulate the existing site drainage to determine the areas effectively drained by present
ditching (i.e., the areas not meeting the criteria for wetland hydrology), and
2) Simulate the predicted number of years each field would meet the criteria for wetland
hydrology in pre- and post-restoration conditions.
In order to run DRAINMOD, the following previously published information was obtained:
1) 40 years (1951 to 1990) of hourly rainfall data and daily high and low temperature data
from New Bern, N.C.;
2) Soil input characteristics as computed by DMSOIL for each soil type (Baumer and Rice
1988): soil-water characteristic curve, volume drained, infiltration/Green-Ampt parameter,
and upward flux;
3) Dates of the local growing season (March 15 to November 11);
4) Wetland hydrology criteria (groundwater within 12 inches of the ground surface for 31
consecutive days 20 out of 40 years (12.5 percent of the growing season (Corps of
Engineers Wetland Delineation Manual, 1987)); and
5) Potential evapotranspiration (PET) factors.
In addition to the above data, Langley and McDonald collected the following field data for each soil
type:
1) Ditch size parameters,
2) Soil horizons and textures (Appendix A),
3) Static water table depths,
4) Average soil hydraulic conductivities (taken as an average over the entire screened section
of well casing) (Appendix C-1), and
5) Average surface storage capacity (Appendix C-2).
Wetland hydrology for the site was simulated with DRAINMOD by uniquely modeling each of the five
soil types with respect to their respective present ditch system. DRAINMOD was used in the single
NCDOT Clayhill Farms Wetland and Stream Mitigation Plan Report July 1999
Langley and McDonald, P.C., Nos. 1960024-203.00 and 1960024-019.00 Page 7
ditch mode because of the high variability in ditch depths and widths. In running the program for a
single ditch, the software assumes a second equally configured ditch is located parallel to the inputted
ditch and that the two ditches are acting as a system. This simulation appeared to produce relatively
accurate results when compared with the present site conditions. This is discussed in further detail in
Section 4.1.1. Ditch spacing was manipulated to determine the current radii of influence of the field
ditches (Appendix C-3).
The existing site conditions modeling shows that site ditches currently "effectively drain" portions of
the agricultural fields at distances ranging from 43 feet to 312 feet for a total of 107.3 acres (Figure 5).
The "effectively drained" areas are dependent upon the soil type, ditch size, topographic relief of the
field, hydraulic conductivity, etc. Effectively drained means that saturation does not occur within 12
inches of the ground surface for 31 consecutive days or longer.
3.5 Surfacewater Hydrology
3 5 1 Development of Hydraulic Geometry Relationships (Regional Curves)
Prior to initiating an on-site analysis of Billy's Branch, research was conducted to determine whether a
regional curve for hydraulic geometry existed for the Upper Coastal Plain of North Carolina. Use of
hydraulic geometry relationships is central to fluvial geomorphological restoration techniques
developed by Leopold (A View of the River, 1994) and Rosgen (Applied River Morphology, 1996), and
recommended for use in North Carolina (N.C. Wildlife Resources Commission, 1998). Regional
curves provide a relationship between various streams in a region by correlating drainage area size to
bankfull discharge rates, cross-sectional area, width and mean depth. Conversations with the Natural
Resources Conservation Service confirmed that no regional curve existed for the Upper Coastal Plain
of North Carolina.
Langley and McDonald then began procedures necessary to develop regional curves. The Water
Resources Data, North Carolina, Water Year 1997 (U.S. Geological Survey 1998), was reviewed to
identify river gage stations throughout the Upper Coastal Plain Region proximate to the Clayhill Farms
Property. A total of 10 sites were identified for review of detailed data (expanded rating,tables,
summary of discharge measurement data (Form 9-207)) obtained from the U.S. Geological Survey
(USGS) in Raleigh. After a review of data and discussions with representatives of the USGS, eight of
the 10 sites were dropped for the following reasons: too deep to be sampled using chest waders (five),
shifting bed and thus changing rating curve (one), gage data only available for three years (one) and
high levels of fecal coliform due to proximity of hog farm (one).
The remaining two sites were used to develop hydraulic geometry data and included: Contentnea Creek
(Meuse River, gage station 02090380) and Mocosin Run (Meuse River gage station 0209096970).
While regional curves become more accurate with data from numerous gage stations, data from these
two sites was felt to be sufficient for geometry relationships because the reference site selected for this
project had the same drainage area and land use characteristics as the restoration reach (Billy's Branch).
Therefore the reference reach could be used as both a "target" for hydraulic geometry relationships at
the restoration reach and as confirmation of the regional curves.
NCDOT Clayhill Farms Wetland and Stream Mitigation Plan Report July 1999
Langley and McDonald, P. C, Nos. 1960024-203.00 and 1960024-019.00 Page 8
Croatan
National
Forest
121 1 B' CMP
DMW-
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DMW-t ?/ ??? j j.
DMW-18,/
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DMW-6
Croatan National Forest
DMW-1
DMW-8

Project #1960024-203.00 & 1960024-019.00

Clayhill Farms
Wetland & Stream Mitigation
Plan Report
Figure 5
DRAINMOD
Existing Conditions
Legend
- - - - Property Boundary
Centerline of Stream
- - - Manmade Ditch
Road
Culvert
DRAINMOD Well
Effectively Drained Areas
(per DRAINMOD)
D1 Ditch Numbers
0-1 Field Numbers
Forested Area
f
RTH
1 "=500' j
-
0 500 1000
t NORTH CAROLINA
DEPARTMENT OF TRANSPORTATION
PROJECT DEVELOPMENT AND
d ENVIRONMENTAL ANALYSIS BRANCH
it
Langley and McDonald, P.C.
landsrnp©WCM}ecla - Environanontal Consultants
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VIRGINA BEACH WILLI ARC
3 5 2 Geomorphological Description of the Reference Reaches
Reference reaches are utilized to describe the plan, profile and cross-sectional attributes of an
unconstrained stream type that is the same stream type as that proposed at the restoration site.
Knowing the dimensions, the bankfull discharge of the reference reach, and the regional curves
correlating bankfull channel dimensions to discharge allows for the design of a stable stream at the
proposed restoration site.
The primary reference reach selected for this study is an unnamed tributary to Hunters Creek, a
tributary of the White Oak River (Figure 1). It is the characteristics of the primary reference reach that
were used to develop the restoration parameters for Billy's Branch. A secondary reference reach,
located within the Clayhill Farms Property, is discussed separately and was utilized to further validate
the most probable stream type of Billy's Branch prior to disturbance.
Primary Reference Reach
The primary reference reach is located within the Croatan National Forest, in Jones County,
approximately 1.4 miles northeast of the Clayhill Farms property. As with Billy's Branch, it drains to
the White Oak River. The reference reach is located in Valley Type X. These valleys are very wide
with low relief typical of coastal plains, broad lacustrine and/or alluvial flats. The reference reach was
located in a watershed 0.7 square miles in size. The entire watershed is forested and contains a
relatively mature forested wetland within the floodplain.
Based upon the hydraulic geometry curves generated for the gage stations, the reference eh was
projected_to-havo bax?cfull: discharge of 42 cubic fg t per second (cfs), cross-sectional area o lquare
on-
feet,,width of 16 feet'and an average depth of 1.5-:Ut. Measurements of bank-full characte ti,
site correlated with these projections quite well: discharge of 40 cfs, cross-sectional area of 14 square
feet, width of 17 feet and average depth of 0.81 feet. Typically cross-sectional area will have the best
correlation with the values from the regional curves since it is an integration of width and depth
(Rosgen, personal communication). Typically average depth will be the least comparable to the data
from the regional curves, as is this case. The reference reach's dimensions are also believed to be
slightly less than those of the regional curve since data for the curve reflects agrarian and suburban land
uses.
A complete Level II morphological description was performed on the reference reach. The
morphological assessment included cross-sections, longitudinal profile, plan form geometry analysis
and channel material inventory. A summary of these findings and illustration of the charmel's typical
riffle cross-section are illustrated in Figure 6. The reach was classified as a C6 stream, possessing a
very high width/depth ratio (21) and containing channel materials of sand, silt and clay. Bank materials
were identical to channel materials. The stream had a broad floodplain (entrenchment ratio of 16.4),
and a relatively low water surface slope (0.002 feet/feet) and a moderate sinuosity (1.2 to 1.8).
The characteristics of this reach were used as a basis to derive channel cross-sections, slope and
geometry for the restoration of Billy's Branch pursuant to the procedures described ill Applied River
NCDOT Clayhill Farms Wetland and Stream Ahtigation Plan Report July 1999
Langley and McDonald, P.C., Nos. 1960024-203.00 and 1960024-019.00 Page 9
Figure 6
Clayhill Farms
Wetland & Stream Mitigation
Plan Report
Reference Reach
Characteristics
Flood Prone Area (95.7 _ _
9e Stream Type: C6
Bankfull (94.1) Bankfull Width (Wbkf): 17'
Mean Depth: 0.8'
Area (Abkf): 14 s.f.
W/D Ratio: 21.3'
Maxium Depth: 2.0'
Width Floodplain: 279'
Entrenchment Ratio: 16.4'
90 - Channel Material(D50): <0.062mm
0 25 50 Water Surface Slope: 0.002 ft/ft
Channel Sinuosity: 1.2 -1.8
Unnamed Tributary to Hunter's Creek Meander Length: 107-140' (6-8 Wbkf)
Radius of Curve: 23-34'
Belt Width: 40'
Meander Width Ratio: 2.4
Critical Shear Stress: 0.09 Ib/s.f.
Extrains: 6mm particle
30
2s
20
NORTH CAROLINA
DEPARTMENT OF TRANSPORTATION
PROJECT DEVELOPMENT AND
ENVIRONMENTAL ANALYSIS BRANCH
SCALE: H. 1"=25'
V. 1"=5'
Project #1960024-203.00 & 1960024-019.00
Morphology (Dave Rosgen, 1996). This procedure was further simplified since the watershed size of
Billy's Branch within the Clayhill Farms Property is virtually identical to this reference reach (0.8 and
0.7 square miles, respectively).
Secondary Reference Reach
A relatively undisturbed tributary to Billy's Branch was identified within the Clayhill Farms Property.
A less complete Level II Assessment was performed on this tributary. The stream section assessed lies
upstream of that portion which was exhibiting head-cutting due to the channelization (downcutting) of
Billy's Branch. The purpose of the abbreviated Level II Assessment was to classify the stream and
determine whether it was also a C Type stream. The stream was determined to be a C6 stream as was
the primary reference reach (Figure 6). This corroboration of findings further strengthened the
conclusion that Billy's Branch was most likely a C6 stream prior to channelization.
3.5.3 Morphological Analysis of Billy's Branch
Billy's Branch and the primary reference reach are located in Valley Type X. Valley Type X is very
wide with gentle slopes and extensive flood plains. This valley type includes coastal plains and broad
lacustrine (lake) flats, both of which often contain peat bogs and/or extensive wetlands.
The length of Billy's Branch was divided into a total of seven nodes, six on-site and a seventh
immediately downstream and off-site. This was done to develop data specific to various reaches of the
stream, its watershed and valley slope (Figure 7). Node points were also intentionally located
immediately up stream and downstream of the large meander at the center of the site (nodes 3 and 4).
This meander is believed to be a natural response to the valley's characteristics because it was
illustrated on the USGS 7.5 minute quadrangle maps (Stella and Hadnot Creek, 1988 and 1984,
respectively), prior to the site's conversion to agricultural use.
The slope of the valley varies noticeably from the western half of the site to the eastern half. The slope
between nodes 1 and 3 is virtually flat. The slope between node 1 and 2 is zero, with a slope between
node 2 and 3 of 0.0009 ft/ft. The slope between node 3, at the top of the large meander, and node 6, at
the confluence with the small tributary, is 0.004 ft/ft. It is steepest in the segment immediately below
the large meander between nodes 4 and 5 (0.009 ft/ft). The valley is also flat between node 6 (on-site)
and node 7 off-site.
As mentioned earlier, Billy's Branch was deepened and straightened in the mid 1970's to facilitate
farming. The excavation of the stream also lowered the water table, to facilitate the cultivation of
commodity crops (see Groundwater Hydrology section).
Three cross-sections were taken along Billy's Branch to perform a Level II Assessment. These
locations roughly correlate with the locations of nodes 4, 5 and 6 (Figure 8). All three of the cross-
sections are similar and describe a G6c stream type (gully). Billy's Branch is narrow (width/depth ratio
of five to six) and deep with a low sinuosity (K of one). This stream has been deepened (incised) to
such an extent that its entrenchment ratio is very low (typically 1.4). Plotting the floodprone elevation
NCDOT Clayhill Farms Wetland and Stream Mitigation Plan Report July 1999
Langley and McDonald, P.C., Nos. 1960024-203.00 and 1960024-019.00 Page 10
Croatan
National
Forest

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Node Indiv.
Drainage
Area Cumulative
Drainage
Area Proposed Channel Characteristics
(at bankfull)
Acres Acres Mil Area Width Avg.Depth Max.Depth
1 66 66 0.1 6' 11' 0.5' 1.2'
2 70 136 0.2 9' 13' 0.7' 1.25'
3 52 188 0.3 10' 15' 0.7' 1.75'
4 103 291 0.45 12' 16' 0.75' 1.8'
5 17 308 0.48 14' 17' 0.8' 1.9'
6 97 4051 0.6 16' 18' 0.9' 2.2'
7* 566 971 1.5 NIA N/A NIA NIA
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* Node 7 is off-site on private property, but was included as a contributing watershed to culverts beneath SR1101
Project #1960024-203.00 & 1960024-019.00
Clayhill Farms
Wetland & Stream Mitigation
Plan Report
Figure 7
Drainage Areas, Nodes
& Proposed Channel
Characteristics
Legend
Property Boundary
Centerline of Stream
-°-••- Manmade Ditch
Road
Culvert
Pine Dominated Forest
Recently Clearcut Forest
\ Hardwood Dominated
Forest
Feeder Ditches
)E 7
I J OPT"
1 500'
0 500 1000
NORTH CAROLINA
DEPARTMENT OF TRANSPORTATION
PROJECT DEVELOPMENT AND
c, fN ENVIRONMENTAL ANALYSIS BRANCH
Langley and McDonald, PC,
E,g,-" S-ey-- Pi-ar,
Lo"dC p, NCh,tO is Env!ronmion101 Conai110n15
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Clayhill Farms
Wetland & Stream Mitigation
Plan Report
Figure 8
Existing & Proposed
Cross Sections
Legend
Property Boundary
Centerline of Stream
-••-••- Manmade Ditch
Road
x Culvert
Pine Dominated Forest
Recently Clearcut Forest
- Hardwood Dominated
Forest
NORTH
1 "=500'
0 500 1000
NORTH CAROLINA
o DEPARTMENT OF TRANSPORTATION
PROJECT DEVELOPMENT AND
a ENVIRONMENTAL ANALYSIS BRANCH
Langley and McDonald, PC,
Eng.news Env-Pato C
Ea?dscapoNChlnclis s Envaonmonta Consul-ts
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VPGINIA BFACH WII IIAM,SNIIHC
Project #1960024-203.00 & 1960024-019.00
indicated that these gullies do not inundate the historic floodplain, which is therefore considered a
terrace (abandoned floodplain). This was confirmed from the results of the HEC-2 model. Model
results for the existing conditions indicated that the two-year flood is contained within the stream
channel (does not exceed the elevations of the top of bank). The results of the HEC-2 model are
described in further detail in Section 3.5.4.
3 5 4 Hydrology and Hydraulics of Billy's Branch and Feeder Ditches
A hydrologic and hydraulic analysis of the proposed wetland and stream mitigation and adjacent
drainage areas was performed to estimate the amount of surface water anticipated on-site during
various rainfall events. Soil Conservation Service (SCS) TR-55 methodologies were employed for the
hydrologic analysis to estimate the volume of runoff for select rainfall events, and to calculate runoff
hydrographs. The design rainfalls of interest include the two-year and ten-year rainfall.events of 24-
hour duration. The 24-hour rainfall depths used for Jones County, North Carolina are 4.5 inches for the
two-year rainfall and 6.72 inches for the ten-year rainfall.
The SCS methodology utilizes the time of concentration and the curve number methods to estimate the
volume of runoff anticipated during a rainfall event. The time of concentration for each drainage area
was estimated by using the kinematic wave formula for overland flow and estimating the velocity for
concentrated flows. Curve numbers were estimated based upon soil types and land use. According to
the Soil Survey of the watershed, the majority of the soils within the watershed are Onslow, Torhunta
and Pantego. All of these loamy soils are classified as hydrologic soil group (HSG) "D" which
indicates soils having very slow infiltration rate when thoroughly wet, and soils that have a permanent
high water table.
The 971 acre watershed consists mainly of forest and crop land (crop land on site only). Based upon
this land use and the underlying soil conditions, a curve number of 77 was utilized to estimate runoff
from the different drainage areas.
The Rational method was used for the smaller drainage areas to estimate the volume of runoff
anticipated during a rainfall event. The Rational method utilizes the rainfall intensity, the runoff
coefficient and the size of the drainage area to calculate the peak runoff (Q = CIA). The rainfall
intensity was based on the intensity-duration-frequency tables for Jones County, North Carolina. The
runoff coefficient was based upon the type of land use which was predominantly agricultural land for
the small drainage areas of the feeder ditches.
The entire watershed drains through a 24-inch and a 48-inch corrugated metal pipe (CMP) that pass
under State Road (SR) 1101. A culvert analysis was utilized to estimate the volume of runoff that can
pass through these two downstream culverts. These culverts were modeled based upon a no
downstream tailwater condition.
The entire 971 acre watershed consists mainly of five drainage areas that are separated by several ditch
systems identified as DA (drainage areas) A, B, C, D and E (Figure 9). The drainage area within the
Clayhill Farms property (DA-A) is approximately 340 acres in size. This drainage area is surrounded
NCDOT Clayhill Farms Wetland and Stream Mitigation Plan Report July 1999
Langley and McDonald, P. C., Nos. 1960024-203.00 and 1960024-019.00 Page 11

f
s ,

Croatan
2r
!, f r

Ifs /
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s
f
Clayhill Farms
Wetland & Stream Mitigation
Plan Report
Figure 9
Drainage Areas of
Billy's Branch
Legend
- - - - Property Boundary
Centerline of Stream
------ --- Manmade Ditch
Road
Culvert
Pine Dominated Forest
Recently Clearcut Forest
- Hardwood Dominated
Forest
l

J
f
0 1 1
N0P'71
1 "=1000'
Approximate
0
0 1000 2000
NORTH CAROLINA
DEPARTMENT OF TRANSPORTATION
(,,F PROJECT DEVELOPMENT AND
\N, ENVIRONMENTAL ANALYSIS BRANCH
`Langley and McDonald, P.C.
LO'td CQ1B NChlBC15-fONfO'i?'1L0'CO'15UYOM6
w,vw.- 'Yelg Cm
VIRGINW BEACH WWILL SBUIRU
Project #1960024-203.00 & 1960024-019.00
on all four sides by drainage ditches. This surrounding ditch system drains south eastward along the
north and south of the drainage area and outfalls through the two culverts located under SR 1101. The
exterior ditch system establishes the size of the main drainage area, but a network of feeder ditches
drains the farm fields to Billy's Branch which acts as a collector ditch. Billy's Branch drains
southeastward to the two culverts under SR 1101. The remaining four drainage areas are located
around all four sides of the Clayhill Farms property.
Drainage area `B" is approximately 66 acres in size and is located to the west of Clayhill Farms. This
drainage area drains through Billy's Branch to reach the two outfall culverts.
Drainage area "C" is approximately 114 acres and is located immediately north of the Clayhill Farms
property. This area drains southward through the perimeter ditch and into Billy's Branch within the
Clayhill Farms property immediately downstream of node 6.
Drainage area "D" is approximately 422 acres and located northeast of drainage area "C". This
drainage area drains southeastward through a tributary east of the Clayhill Farms property. It
discharges to Billy's Branch downstream of the Clayhill Farms property (off-site) at node 7.
Drainage area "B" is approximately 30 acres and borders the Clayhill Farms property to the south. This
drainage area drains southeastward through the ditch located along the southern border of the Clayhill
Farms property and joins with Billy's Branch downstream of the subject property.
Feeder Ditches
There are several feeder ditches located on-site that drain the site into Billy's Branch (Figures 7 and 9).
Seven of these feeder ditches are located in the southwest corner of the site and were man-made to
drain the land for agricultural use. Four more feeder ditches are located in the southeast corner of the
site. For simplification, all the runoff east of ditch 10 was modeled as though it was conveyed by ditch
10 alone, and not ditch 10 and 11.
These ten drainage ditches were analyzed for existing conditions under the peak flow rates from the
two-year and ten-year rainfall events. The rational method was used to calculate the existing peak flow
rates for each individual drainage ditch. The individual peak flow rates were analyzed in the typical
cross section of the downstream end of each drainage ditch, based on the Manning equation.
Additionally, the capacity of each individual drainage ditch was computed based on the typical
downstream cross section. The following table shows the peak flow rate for both the two-year and ten-
year rainfall event, and correlating water surface elevation, the top of bank at the downstream end of
the ditch, and the peak flow rate capacity for each of the individual feeder ditches. It should be noted
that none of the elevations of the peak flow exceed that of the top of bank for either the two- or ten-year
storm. Therefore the ditching on-site is so incised (deepened) that the historic floodplain on-site has
been abandoned (now acts as a terrace).
NCDOT Clayhill Farms Wetland and Stream Mitigation Plan Report July 1999
Langley and McDonald, P. C, Nos. 1960024-203.00 and 1960024-019.00 Page 12
Tahle 2- F,xisting conditions of feeder ditches.
2-Year Storm 10-Year Storm
Ditch Drainage Capacity Top of Flow Rate , Water Elev. Flow Rate , Water Elev.
# Area ac cfs Bank ft cfs ' ft cfs ' ft
1 12.1 41.6 33.0 12.6 , 32.0 17.0 , 32.3
2 12.6 79.8 33.0 14.4 ; 31.3 19.3 ; 31.6
3 12.4 101.1 33.0 10.6 ; 31.0 14.6 ; 31.2
4 8.7 62.0 33.1 10.7 ; 31.0 14.2 ; 31.3
5 9.5 136.4 33.2 11.8 ; 30.6 15.6 ; 30.7
6 15.5 95.4 32.0 16.9 ; 30.5 22.8 ; 30.6
7 8.6 167.3 32.0 10.2 ; 29.7 13.7 ; 29.8
8 11.6 127.7 25.0 16.9 ; 22.9 22.0 ; 23.6
9 4.3 230.6 26.0 6.7 ; 24.2 8.7 ; 24.3
10 3.7 415.0 26.2 5.5 ; 24.1 7.1 ; 24.2
Billy's Branch
In order to model the surface water profile of Billy's Branch, the peak flow rates for each individual
drainage area had to be calculated along with the total peak flow rate from the watershed. The Soil
Conservation Service (SCS) methodology was used to estimate the'peak flow rates for both the two-
year and ten-year rainfall event. The SCS TR-55 methodology was used to estimate the time of
concentration for the individual drainage areas. The peak time of concentration of 3.5 hours from
drainage area "D" was then used to estimate the peak flow rate for the watershed. The SCS method has
a time of concentration (T j limit of two hours. In order to represent the hydrograph for the 3.5 hour
time of concentration, a modified hydrograph was produced based on the ratio of the peak runoff rates
from the Tc of 2.0 hours and the T. of 3.5 hours. The peak runoff rate of 323 cfs was used for the two-
year rainfall event and 614 cfs was used for the ten-year rainfall event. The following table shows the
time of concentration and the peak runoff rates for each individual drainage area.
Tahle 3- Peak flow rates of each drainage area.

Drainage
Area Size of
Drainage Area
(acres) Time of
Concentration
(hours) Peak Runoff
2-Year Storm
(cfs) Peak Runoff
10-Year Storm
(cfs)
A71 70 1.87 35 67
A-2 52 2.14 57 110
A-3 120 2.38 105 201
A-4 97 2.64 138 264
B 66 1.54 38 73
C 114 1.79 59 113
D 422 3.56 142 270
E 30 2.11 14 27
Peak Runoff Rate Criteria 971 3.56 323 614
NCDOT Clayhill Farms Wetland and Stream Mitigation Plan Report July 1999
Langley and McDonald, P. C., Nos. 1960024-203.00 and 1960024-019.00 Page 13
The two downstream outfall culverts (24-inch CMP and 48-inch CMP) were analyzed to see if they
could convey the peak flow rates from the watershed's two-year and ten-year rainfall events. The
culvert analysis showed that the peak flow rates will exceed the capacity of the combined two culverts
and the stormwater runoff ponds behind the two existing outfall culverts.
The existing culvert condition was therefore modeled as a pond with the two culverts acting as the
controlling outfall structures. The top elevation of SR 1101 at the location of the culverts was used as
the maximum pond elevation. The model of the pond routing estimated a storage elevation of 22.7 feet
for the two-year rainfall event. The estimate for the ten-year rainfall event was a storage elevation that
exceeds the elevation of SR 1101.
A telephone conversation with the Regional North Carolina Maintenance Division and the Regional
Highway Maintenance Engineer revealed that the Maintenance Division has not received a complaint
of stormwater runoff overtopping SR 1101 at the location of these two culverts. Furthermore, the
Maintenance Division has not had to perform any repairs at this location for as far back as the
Maintenance Division representatives could remember.
Based on the information provided by the Regional Maintenance Division and the Regional Highway
Maintenance Engineer, it was decided that the estimated peak flow rates for the ten-year rainfall event
were too conservative. The estimated peak flow rates for the two-year rainfall event were therefore
believed to be more realistic. The road elevation of SR 1101 is approximately 24.0 feet to 24.5 feet
which is approximately 1.3 to 1.8 feet higher then the estimated two-year peak storage elevation 22.7
feet.
The surface water profile of Billy's Branch ditch was modeled using the HEC-2 program to analyze the
existing and proposed peak flow depths within Billy's Branch and the amount of flooding outside of
Billy's Branch as a consequence of modifying the ditch and longitudinal profiles. The model is based
on several cross sections (nodes) located along Billy's Branch and the correlating peak stormwater
runoff rates at those sections (Figure 9). As a means of being conservative, the peak runoff rate for
each cross section (node) is based on the time of concentration for each smaller drainage area. The
peak storage elevation of 22.7 feet (estimated from the pond routing model) was used to establish the
tailwater elevation at the downstream end of Billy's Branch. Table 4 shows the estimated water surface
elevations at the modeled cross sections (node) and their corresponding top of bank.
Table 4. Existing surface water profile of Billy's Branch.
Node # Peak Stormwater Runoff (cfs) I Water Surface Elevation (ft)
7 323 22.70
6 176 22.69
5 148 24.57
4 143 24.49
3 95 31.81
2 73 32.71
1 38 32.94
NCDOT Clayhill Farms Wetland and Stream Mitigation Plan Report July 1999
Langley and McDonald, P. C., Nos. 1960024-203.00 and 1960024-019.00 Page 14
3.6 Plant Communities
Approximately 213.8 acres of Clayhill Farms are presently forested (11.7 of which has been recently
clearcut), and 141.8 acres are fallow agricultural fields. As mentioned earlier, Clayhill Farms was
ditched and subsequently logged in the 1970s. Fire has been excluded from the property for at least the
last 30 years, and it was farmed continuously until 1998. The result of these manipulations has been
that natural communities presently occur on only small, fragmented patches of the property. A list of
all plant species identified during field investigations at Clayhill Farms is included in Appendix E.
3.6.1 Pine Dominated Communities
Approximately 193.8 acres of the site is 25 to 30 year old pine regeneration (Figure 2). Approximately
44.1 acres of this community (primarily in that area south of the dirt road bisecting the forest and west
of the tributary to Billy's Branch) has been thinned in the past five years. The thinned area contains an
overstory of loblolly pine (Pinus taeda) and pond pine (Pinus serotina) in the six-inch diameter class.
The un-thinned area contains primarily loblolly pine in the four-inch diameter class.
Common understory trees include sweetgum (Liquidambar styraciflua), swamp blackgum (Nyssa
sylvatica var. biflora), titi (Cyrilla racemiflora), sweet bay (Magnolia virginiana), red bay (Persea
borbonia), laurel oak (Quercus laurifolia), and red maple (Acer rubrum). Post oak (Quercus stellata)
and blackjack oak (Quercus marilandica) are present on the drier portions of the site. The shrub layer
is tall and dense, consisting primarily of inkberry (Ilex glabra). The herbaceous layer is sparse except
along openings and in the ecotones between the pine and hardwood communities. It consists mainly of
Virginia chain fern (Woodwardia virginica), bracken fern (Pteridium aquilinum), cinnamon fern
(Osmunda cinnamomea), and dwarf huckleberry (Gaylussacia dumosa). A well developed vine layer
exists, especially in the wetter portions of the site, and is comprised mainly of greenbriers (Smilax
laurifolia, S. rotundifolia, and S. bona-nox) and yellow jessamine (Gelsemium sempervirens).
3.6.2 Hardwood Dominated Communities
About 1.9.0 acres of the property is hardwood dominated forest (Figure 2). Approximately 15.9 acres
of this is mixed mesic hardwood forest with a variety of oaks (including water oak (Quercus nigra),
laurel oak, post oak, blackjack oak, swamp chestnut oak (Quercus michauxii), and southern red oak
(Quercus falcata var. falcata)), yellow-poplar (Liriodendron tulipifera), sweetgum, red maple and
scattered loblolly pine in the overstory. American holly (Ilex opaca) is prevalent in the understory.
This community occurs at the southeastern corner of the forested area and along the northern boundary
of Billy's Branch, primarily on Marvyn and Onslow soils.
The remaining 4.1 acres of hardwood forest is coastal plain bottomland hardwood forest. This forest
type is primarily on Onslow and Muckalee soils and is adjacent to Billy's Branch and its tributaries.
Due to the channelization of Billy's Branch, portions of this community (1.8 acres) have been drained
and are no longer functioning as a floodplain but rather as a terrace. Approximately 2.3 acres of this
community exists in its natural state. The 1.8 acres of drained bottomland hardwood forest adjacent to
Billy's Branch still meet, marginally, the hydrology requirements of jurisdictional wetlands.
NCDOT Clayhill Farms Wetland and Stream Mitigation Plan Report July 1999
Langley and McDonald, P. C., Nos. 1960024-203.00 and 1960024-019.00 Page 15
Common overstory trees in the bottomland hardwood forest include swamp blackgum, yellow-poplar,
water oak (Quercus nigra), red maple, sweetgum, and scattered loblolly pine. This community has a
fairly open understory with a dense herbaceous layer including cinnamon fern, royal fern (Osmunda
regalis), and netted chain fern (Woodwardia areolata).
3 6 3 Recent Clearcuts and Open Areas
Vegetation growth in both the fallow fields and the clearcuts is less than one year old and is typical of
early successional communities in the coastal plain of North Carolina. The fields are dominated by
field garlic (Allium vineale) and wild onion (Allium canadense), with toad-flax (Linaria canadensis),
goldenrods (Solidago spp.), dog fennel (Eupatorium capillifolium), and ragweed (Ambrosia
artemisiifolia) beginning to appear. The clearcuts are more diverse, with the seeds and rhizomes of
many species having lain dormant in the litter layer until presented with the increased light intensities
created by the clearcuts. Species here include those in the fields as well as pink sundew (Drosera
capillaris), bladderwort (Utricularia sp.), dwarf azalea (Rhododendron atlanticum), orange milkwort
(Polygala lutea), greenbriers, and Japanese honeysuckle (Lonicera japonica). The coppice
(regeneration) of hardwood stumps also plays a major role in the clearcuts.
3.6.4. Protected Species and Ecologically Significant Communities
While no specific protected species surveys were performed at Clayhill Farms, no protected plant
species were observed during the extensive fieldwork performed there. A letter received from the N. C.
Natural Heritage Program November 19, 1997 stated that a recorded population of the State
Endangered/Federal Species of Concern Carolina goldenrod (Solidago pulchra) occurs approximately
1.0 miles northwest of the property (L&M 1998). No plant species requiring Section 7 consultation are
listed for Jones County.
The N. C. Natural Heritage Program maintains a list of natural communities they feel have ecological
significance due to their rarity or pristineness. Clayhill Farms is contiguous to the Registered
Significant Natural Heritage Area (SNHA) Croatan National Forest Megasite and lies approximately
1.0 miles northeast (upstream) of the Registered SNHA Hunters Creek Upland Forest. The latter
contains four high quality natural areas: dry mesic oak/hickory forest, mixed mesic hardwood forest,
tidal cypress-gum swamp, and coastal plain small stream swamp.
3.7 Wetlands
The location of all jurisdictional wetland boundaries at Clayhill Farms was flagged in the field during
March and May 1999. All delineations were based on the Corps of Engineers Wetland Delineation
Manual (1987). Mr. Mike Bell, of the Wilmington District of the U.S. Army Corps of Engineers,
visited the site in late March 1999 to review the wetland delineation in progress. A field map showing
the approximate location of the flagged lines has been forward to Mr. Bell for review, and he has
indicated no concerns regarding it.
NCDOT Clayhill Farms Wetland and Stream Mitigation Plan Report July 1999
Langley and McDonald, P. C., Nos. 1960024-203.00 and 1960024-019.00 Page 16
The NCDOT Division 2 Location and Surveys Unit (under the direction of Mr. Terry Wheeler, P.E.,
R.L.S.) located the flagged lines using GPS in May 1999 (Figure 10). Based upon this survey, 155.9
acres of Clayhill Farms are presently jurisdictional wetlands. A survey exhibit will be forwarded to
Mr. Bell for his signature in early July.
3.8 Wildlife
3.8.1 Commonly Observed Species
The Clayhill Farms property possess wildlife typical of coastal plain pine flatwoods and mixed
hardwood stands. White-tailed deer (Odocoileus virginianus) and black bears (Ursus americanus) are
commonly observed, as well as many small mammals such as raccoons (Procyon lotor), opossums
(Didelphis virginiana), gray foxes (Urocyon cinereoargenteus), red foxes (Vulpes vulpes), gray
squirrels (Sciurus carolinensis), and eastern cottontails (Sylvilagus floridanus). There is no doubt that a
number of songbirds, woodpeckers, owls and raptors also frequent the site. A list of all wildlife species
identified at Clayhill Farms during field investigations (from visual observation or evidence of the
animals) is included in Appendix E.
3.8.2 Protected Species
No specific protected species surveys have been performed at Clayhill Farms to date. However, no
protected animal species were observed during the extensive fieldwork performed there. A review of
NHP records in June 1999 revealed a recorded occurrence of the State Significantly Rare/Federal
Species of Concern Croatan crayfish (Procambarus plumimanus) at the southeastern corner of the
property in 1975. Although not afforded protection under the Endangered Species Act, Federal Species
of Concern are rare species which could be listed at any time.
The species description and biological conclusion of "Unresolved" is included here for the only animal
species requiring Section 7 consultation which is listed for Jones County, the red-cockaded woodpecker
(Picoides borealis).
Picoides borealis (red-cockaded woodpecker) E
Family: Picidae
Federally Listed: October 13, 1970
Distribution in N.C.: The sandhills and southern coastal plain; scattered populations also live
in the northern coastal plain and the extreme eastern Piedmont.
Species Account: "The red-cockaded woodpecker (RCW) is 18 to 20 centimeters long with a
wing span of 35 to 38 centimeters. There are black and white horizontal stripes on its back, and
its cheeks and underparts are white. Its flanks are black streaked. The cap and stripe on the side
of the neck and the throat are black. The male has a small red spot on each side of the black cap.
After the first post fledgling molt, fledgling males have a red crown patch. This woodpecker's
diet is composed mainly of insects which include ants, beetles, wood-boring insects, caterpillars,
and corn ear worms if available. About 16 to 18 percent of the diet includes seasonal wild fruit."
NCDOT Clayhill Farms Wetland and Stream Mitigation Plan Report July 1999
Langley and McDonald, P. C., Nos. 1960024-203.00 and 1960024-019.00 Page 17
Croatan
National
Forest
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Clayhill Farms
Wetland & Stream Mitigation
Plan Report
Figure 10
Wetland Delineation Map
Legend
Property Boundary

Centerline of Stream
-°- - Manmade Ditch
R
d
oa
Culvert
Forested Area
Recently Clearcut Area
Groundwater Monitoring
Well
DRAINMOD Well
Jurisdictional Wetlands
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7 0 500 1000
w t NORTH CAROLINA
DEPARTMENT OF TRANSPORTATION
PROJECT SR???? „off ENVIRONMENTAL DEVELOPMENT N
ANALYSIS RANCH
Langley and McDonald, PC.
F,gI?,s-Suom, Pa-:.:,.?.
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VI7GMA BFACH LLWMSB OC
Project #1960024-203.00 & 1960024-019.00
"Egg laying occurs during April, May, and June with the female utilizing her mate's roosting
cavity for a nest. Maximum clutch size is seven eggs with the average being three to five eggs.
From egg laying to fledging requires about 38 days, and then another several weeks are needed
before the young become completely independent. Most often, the parent birds and some of their
male offspring from previous years form a family unit called a group. A group may include one
breeding pair and as many as seven other birds. Commonly, these groups are comprised of three
to five birds. Rearing the young birds becomes a shared responsibility of the group. However, a
single pair can breed successfully without the benefit of the helpers." (USFWS 1993)
Habitat: "Open stands of pines with a minimum age of 80 to 120 years, depending on the site,
provide suitable nesting habitat. Longleaf pines (Pinus palustris) are most commonly used, but
other species of southern pine are also acceptable. Dense stands (stands that are primarily
hardwoods, or that have a dense hardwood understory) are avoided. Foraging habitat is provided
in pine and pine hardwood stands 30 years old or older with foraging preference for pine trees 10
inches or larger in diameter. In good, well-stocked, pine habitat, sufficient foraging substrate can
be provided on 80 to 125 acres."
"Roosting cavities are excavated in living pines, and usually in those which are infected -with a
fungus producing what is known as red-heart disease. The cavity tree ages range from 63 to 300
plus years for longleaf, and 62. to 200 plus years for loblolly and other pines. The aggregate of
cavity trees is called a cluster and may include 1 to 20 or more cavity trees on 3 to 60 acres. The
average cluster is about 10 acres. Completed cavities in active use have numerous, small resin
wells which exude sap. The birds keep the sap flowing apparently as a cavity defense mechanism
against rat snakes and possibly other predators. The territory for a group averages about 200
acres, but observers have reported territories running from a low of around 60 acres, to an upper
extreme of more than 600 acres. The expanse of territories is related to both habitat suitability
and population density." (USFWS 1993)
Biological Conclusion: Unresolved
A letter received from the N. C. Natural Heritage Program (NHP) November 19, 1997, stated
that a cavity tree was recorded on the southeastern corner of the property in 1975 and that two
active colonies were observed on Forest Service Road 144 within one mile of the site in 1992
(L&M ' 1998). However, a review of NHP records in June 1999 revealed that the recorded
occurrence of a cavity tree on the property was incorrect (the record was for the Croatan
crayfish (Procambarus plumimanus) not the red-cockaded woodpecker).
The largest pines on the Clayhill Farms property are smaller than those preferred by the RCW
for foraging as they are typically in the eight-inch diameter class with most being in the four to
six-inch diameter classes. In addition, the stands are much thicker than that typical of RCW
habitat. As such, no nesting or foraging habitat is believed to presently occur on the site.
However, the NCDOT will conduct a RCW survey at Clayhill Farms during the summer/fall of
1999 to resolve the biological conclusion for this species.
NCDOT Clayhill Farms Wetland and Stream Mitigation Plan Report July 1999
Langley and McDonald, P. C., Nos. 1960024-203.00 and 1960024-019.00 Page 18
It is anticipated that due to the perpetual conservation easement that will be placed on the
property, foraging and nesting habitat for the RCW will be created at Clayhill Farms over
coming decades. As such, the NCDOT has contacted the U. S. Fish and Wildlife Service
regarding the possibility of obtaining RCW mitigation credit for Clayhill Farms.
4.0 PROPOSED CONDITIONS
The following sections detail the proposed methods for restoring and preserving the natural
communities at Clayhill Farms. Conceptual plans are included to further depict the proposed
conditions at the site.
4.1 Hydrology Modifications
4.1.1 DRAINMOD Results
Site conditions at all ditches were simulated for existing and proposed conditions using DFAINMOD
(as described in Section 3.4.3). "Wet years" are years in which the groundwater table remains within
12 inches of the ground surface for greater than 31 consecutive days (12.5 percent of the growing
season). "Ponded years" are years in which the groundwater table remains above the ground surface
for greater than 31 consecutive days. To be conservative, the 12.5 percent hydrology criterion was
chosen instead of the five percent criterion.
All proposed conditions assume that Billy's Branch would be filled to the present top of bank and that
each ditch would be blocked to grade at their downstream confluence with Billy's Branch. Table 5 lists
the number of years (out of 40) for which the present fields would meet the 12.5 percent wetland
criteria. A field was considered to possess wetland hydrology (and therefore no longer be effectively
drained) if 50 percent (20 out of 40) or more of the years modeled were "wet years". Figure 11 depicts
those areas which would remain effectively drained after restoration. As indicated by the model, only
field M-1 was effectively drained both before and after restoration (Figures 5 and 11).
The results of DRAINMOD indicate that under existing conditions many of the fields pond for
durations exceeding the 12.5 percent wetland hydrology criterion in a majority of the 40-year modeling
period. This finding conflicts with the comments of the pervious owner who stated that the fields never
had a flooding problem (long duration of inundation impairing crop yields). Unfortunately , the
absence of a near surface groundwater table during the early growing season this year precluded a
comparison of groundwater observations and model results.
To standardize DRAINMOD results, absolute values for post-restoration were not considered to be
precise but were instead compared in relative terms to the pre-restoration results. For example, the
number of years that the fields of Marvyn soil were saturated/ponded under post-restoration conditions
did not increase substantially over pre-restoration conditions (an increase of only seven and four years
respectfully). Conversely, the response of the Onslow fields was much more substantial) an average of
NCDOT Clayhill Farms Wetland and Stream Mitigation Plan Report July 1999
Langley and McDonald, P. C., Nos. 1960024-203.00 and 1960024-019.00 Page 19
Croatan
National
Forest
(2) 18' CMP
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Clayhill Farms
Wetland & Stream Mitigation
Plan Report
Figure 11
DRAINMOD
Proposed Conditions
Legend
Property Boundary
Centerline of Stream
- - - Manmade Ditch
Road
Culvert
DRAINMOD Well
Effectively Drained Areas
(per DRAINMOD)
rw Forested Area
I
a
UMW-1
MA 12 ,
- DMW-11
1"=500'
0 500 1000
MW-9 e .
NORTH CAROLINA
DEPARTMENT OF TRANSPORTATION
l
PROJECT DEVELOPMENT AND
SR1?/ ENVIRONMENTAL ANALYSIS BRANCH
Langley and McDonald, PC.
Nig?x?is SuiveyweNu?iiers
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Project #1960024-203.00 & 1960024-019.00
Table 5. Pre and post-restoration DRAINMOD field simulations for the 40-year modeling period.
Pre-Restoration Post-Restoration
Soil Type Field # Wet Years , Ponded Years Wet Years , Ponded Years
Marvyn M-1 7 , 2 14 , 6
M-1 & 2* 14 ; 6 28 ; 12
0-1 32 , 26 38 , 38
Onslow 0-2 20 , 15 33 ; 30
O-3 7 ; 6 22 ; 16
T-1N 29 , 20 40 , 39
T-1S 33 ; 33 40 ; 38
T-2N 29 ; 20 40 ; 39
T-2S 33 ; 33 40 ; 38
T-3N 29 ; 20 40 ; 39
T-3S 33 ; 33 40 ; 38
Torhunta T-4N 25 ; 13 40 ; 39
T-4S 29 ; .23 40 ; 36
T-5N 33 ; 27 39 ; 39
T-5S 33 ; 33 40 ; 39
T-6 33 ; 33 40 ; 39
T-7 28 ; 19 40 ; 37
Pantego P-1N 33 , 30 40 , 40
P-1S 36 ; 34 40 ; 40
*a,zclhnwn nn FimirP 5 M-1 is the northern nortion of the easternmost field and M-2 is the southern portion o:
that field. They were analyzed separately because ditch 11 does not extend into the southern portion of the
field.
11 and 12 year increases in saturation and ponding respectively). The increases for Torhunta and
Pantego fields were also quite substantial.
Consequently, there was a concern that the substantial increase in frequency of saturation and
inundation for all but the fields of Marvyn soil could lead to unacceptable levels of mortality of young
tree seedlings after planting. As such, a sensitivity model was developed for two fields (T-2S and 0-1)
to assess how saturation and ponding results varied as a result of blocking the ditch at various elevation
relative to the top of bank. The objective was to maximize saturation while minimizing ponding. As
shown in Table 6, the results indicate that surface ponding appears to increase most substantially when
ditch blocks are increased from 0.5 feet below grade to the top of bank. Additionally, there is little
change in frequency of saturation/ponding when the ditch pugs are raised from 1.0 foot below grade to
0.5 feet below grade. For these reasons, it is recommended that all ditch blocks be installed to 0.5 feet
below grade except for ditches D-9, D-10 and D-11 (Figure 12). Ditch blocks for these three ditches
should be installed to the top of bank elevation to maximize the frequency of saturation.

NCDOT Clayhill Farms Wetland and Stream Mitigation Plan Report July 1999
Langley and McDonald, P. C., Nos. 1960024-203.00 and 1960024-019.00 Page 20
Croatan' LI
National
Forest
(/V 33)
,ru
Croatan
? / goco? -moo ? ?? ?
370 ?\ '•
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1
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Planview Detail
Stream Alignme Scale: 1"-50'
nt for Node 5
Proposed
Meander Length 162'
Proposed Radius of Curviture = 34' Proposed Radius of Curviture = 40'

N L
0?
_
.

Proposed K = 1.25 Proposed K = 1 28
Top of Bank Proposed Existing
Centerline of Stream Proposed -- - Existing
27.
p0o -
C 310
J,o
330
JJO Jaa
"Note: Berm may be needed along western
border of farm field bordering
Croatan National Forest.
Clayhill Farms
Wetland & Stream Mitigation
Plan Report
Figure 12
Existing & Proposed
Stream Plan View & Detail
Legend
- - - - Property Boundary
Centerline of Stream
------ -
Manmade Ditch
Road
Culvert
Pine Dominated Forest
Recently Clearcut Forest
Hardwood Dominated
Forest
Floodplain Area
New Stream
-- Ditch Block/Fills
Oxbow Lakes
Borrow Area
AORTH
1 "=500'
II
0 500 1000
NORTH CAROLINA
DEPARTMENT OF TRANSPORTATION
141 a PROJECT DEVELOPMENT AND
ENVIRONMENTAL ANALYSIS BRANCH
J Langley and McDonald, PC.
Englnalt -surf-1-al
L?J U tandsr?e Prrhllwls E nJ?ronmontnlo C
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VIRGINW BEACH MLIAMSBURG
Project #1960024-203.00 & 1960024-019.00
Table 6. Sensitivity model for assessing DRAINMOD saturation and ponding results (number of
years out of 40).
Field T-2S Field 0-1
Ditch Condition Saturation* , Ponding* Saturation* , Ponding*
Ditch filled to surface (T.O.B.) 40 (7) , 38 (5) 38 (6) , 38 (12)
Ditch filled to 0.5 ft below grade 36 (3) ; 33 (0) 34 (2) ; 33 (7)
Ditch filled to 1.0 ft below grade 36 (3) i 33 (0) 34 (2) ; 32 (6)
Ditch in existing condition 33 ; 33 32 ; 26
* (#) reflects difference in value from existing condition (ditch open).
Due to the topography of the site in the vicinity of Billy's Branch, DRAINMOD models Billy's Branch
to be six feet deep even if it is completely filled. As such, areas around Billy's Branch are considered
effectively drained by the model in post-restoration. Based on data discussed in Sections 4.1.2 to 4.1.5
below, Billy's Branch will not effectively drain any areas after restoration but is instead anticipated to
raise the water table of adjacent areas and restore the former floodplain.
4 1 2 Proposed Cross-Sections and Geometry of Billy's Branch
The procedures used to develop the proposed restoration of Billy's Branch follow those developed by
Rosgen and presented in his course entitled "Fluvial Geomorphology for Engineers" and the paper
entitled A Geomorphological Approach to Restoration of Incised Rivers (1997). Billy's Branch will
be converted from a G6c to a C6 stream type. Both the primary reference reach (off-site) and the
secondary reference reach (on-site) were C6 streams.
The proposed cross-sectional area of Billy's Branch for each node was derived by relating the area of
the contributing watershed to the regional curve for drainage area versus stream cross-sectional area.
Widths and average depths were derived for each node point using the width depth ratio calculated for
the riffle section at the reference reach. These results, and proposed maximum depths are tabulated on
Figure 7.
Proposed stream geometry (meander length, radius of curvature, belt width) were then derived for each
node of Billy's Branch. This was done by developing ratios from data derived from the reference
reach. Each criteria mentioned above was calculated as a ratio of the width of the bankfull cross-
section. These ratios were then multiplied by the bankfull width from each node of Billy's Branch to
derive the geometry required at each node. An example of these findings is. provided on Figure 12.
The geometry for each node was then superimposed on topographic mapping (1 inch = 50 feet)
provided by the NCDOT.
4.1.3 Proposed Alignment of Billy's Branch
The assessment of stream restoration options for Billy's Branch followed that of Rosgen (A
geomorphological Approach to Restoration of Incised Rivers, 1997). The prioritization of restoration
options described in the above mentioned manuscript is as follows (in descending order of preference):
NCDOT Clayhill Farms Wetland and Stream Mitigation Plan Report July 1999
Langley and McDonald, P. C., Nos. 1960024-203.00 and 1960024-019.00 Page 21
Convert G and/or F stream types to C and/or E types at elevations sufficient to restore the
floodplain at the pre-disturbance elevation,
Convert G and/or F stream types to C and/or E types and, establish floodplain at current
elevation or higher, but not as high as the pre-disturbance elevation,
• Convert to a new stream type without an active floodplain, but containing a floodprone area,
• Stabilize channel in place.
The objectives of this study were to re-establish a stable stream type and floodplain at the pre-
disturbance elevation. Additionally, another goal was to create the new stream channel within the
floodplain. Creation of a new stream channel avoids the problems of stabilizing a new stream bed
within an existing channel (Dave Rosgen, 1999). Material needed to fill the existing stream comes
from the proposed stream together with small, oxbow lakes constructed in the immediate area (Dave
Rosgen, 1999) of the project, or from borrow areas. In many cases, however, creation of a new stream
bed cannot be performed (e.g. narrow floodplain and presence of structures).
Representatives Croatan National Forest were contacted and asked if the National Forest Service would
be interested in allowing stream restoration on that portion of their property located between Clayhill
Farms and SR 1101. The National Forest Service was not interested in restoring this relatively small
reach. Therefore the proposed stream restoration project will lie entirely within Clayhill Farms and a
grade control structure (e.g. step pool) will be needed to transition the streams slope from the Clayhill
Farms property to the National Forest Service lands.
In summary, the restoration goal for Billy's Branch was to restore the stream at elevations which would
re-establish use of the historic floodplain. It was also a goal to place the stream in a new location
(alignment) wherever possible as discussed above. A new alignment of the stream is proposed above
node 3 since the earthwork will be relatively small and can take advantage of an existing dirt road. The
proposed stream alignment between nodes 3 and 6 however, must closely follow the existing
alignment. This is necessary due to the steeper slope of the valley and the narrower floodplain below
node 3. However, sinuosity below node 3 will increase above that of the existing incised and
straightened stream. Figure 12 illustrates the proposed stream's alignment and the typical plan view for
node 5 as a representation of the general geometry for the each segment downstream of node 3. This
increase in sinuosity will increase the stream length from 6,170 linear feet (M) to 7,410 l.f. Final
design of stream geometry will vary along each reach where practicable to give the stream a natural
appearance. A more detailed analysis of meander geometry is provided below.
Based upon the plan view, channel dimensions and valley slope calculated for each node of Billy's
Branch, the bankfull critical shear stress was calculated and compared to that calculated for the
reference reach (0.09 lbs/f') and the particle sizes found within Billy's Branch. Shear Stress is an
important calculation because it indicates whether the stream has the power to entrain particles smaller,
equal to, or larger than the particle sizes available to the channel when the stream is at its bankf ill
stage. A proposed stream design which generates a shear stress value in excess of that needed to move
NCDOT Clayhill Farms Wetland and Stream Mitigation Plan Report July 1999
Langley and McDonald, P. C., Nos. 1960024-203.00 and 1960024-019.00 Page 22
the particles available to the stream bed indicates that the stream will begin to down-cut (scour) its bed.
Conversely, a proposed stream design with too little shear stress will not be able to transport the
sediment made available to it, causing sedimentation and loss of sediment transport competency.
The initial meander geometry calculated for nodes 1, 2 and 3 of Billy's Branch generated a shear stress
that matched that of the reference reach and the size of the sediment available. There is also adequate
area upstream of node 3 to place the stream on a new alignment, as is preferred. The new alignment
was placed in the woods immediately north of the existing stream. This alignment was selected to
avoid losing wetland restoration opportunities in the Prior Converted cropland. This new alignment
also allows the dirt road in the woods to be used for construction. Although the berm immediately
south of the channelized stream will be used to fill in the existing channel, additional fill material will
be needed. This additional fill will come from grading certain areas immediately around the new
stream alignment, which are approximately one foot higher than necessary.
The initially proposed stream geometry between nodes 3 and 4 yielded a shear stress too great
compared to the reference reach (0.3 versus 0.09 lb/ff2, see Figure 13). Various options are available to
decrease shear stress: increase width/depth ratio, increase sinuosity (decrease slope), increase meander
width ratio, decrease meander length and radius of curvature. Increasing the width/depth ratio was
found to be unsuccessful since the values necessary for width and depth were well outside the range
observed at the reference reach (normalized for drainage area). Consequently, increases in sinuosity
were attempted to decrease stream slope and thereby reduce shear stress (Figure 13). The only means
available to reduce the shear stress to that necessary was to increase sinuosity from 1.2 to 2.4. This was
accomplished by having a meandering plan view follow the large, remnant meander pattern of Billy's
Branch. This finding is significant because it confirms that the historic meander pattern (observed on
USGS quadrangle maps prior to agricultural use) was needed to maintain a stable stream through this
narrowing and steepening portion of the valley (see alternative versus proposed stream alignment,
Figure 13).
The meander geometry between nodes 4 and 6 only requires a sinuosity of between 1.25 and 1.30 to
generate acceptable shear stress values. An illustration of the restoration geometry is provided in
Figure 12.
Once the plan, profile and cross sections were calculated, the data was then input into the HEC-2 model
to determine peak flood elevations for the two-year storm and the peak discharge rate occurring at the
culverts on SR 1101. This is further discussed in the Proposed Hydraulics section of the report.
4.1.4 Proposed Hydraulics
The individual drainage areas and the time of concentration for the five drainage areas will remain the
same under the proposed conditions. The five individual drainage areas will continue to drain into, and
pond behind, the two out-fall culverts (24-inch CMP and 48-inch CMP) located under SR 1101. The
proposed conditions include: 1) reducing the slope of the longitudinal profile, 2) increasing stream
length (due to increased sinuosity) and 3) reducing the cross-sectional area of Billy's Branch and 4)
partially blockki +hp P1P?,Pn feeder ditches that drain to Billy's Branch.
NCDOT Clayhill Farms Wetland and Stream Mitigation Plan Report July 1999
Langley and McDonald, P. C., Nos. 1960024-203.00 and 1960024-019.00 Page 23
A
azs?
I
Figure 13
32
'r ? ?,
Valley Slope: 0.0088
Sinuosity: 1.75
Stream Slope: 0.005
Shear Stress: 0.22 Ib/s.f.
Entrains: 12mm particle
Proposed Stream Course Alignment & .
Corresponding Bankfull Shear Stress
\
Valley Slope: 0.0088
Sinuosity: 1.2
Stream Slope: 0.007
Shear Stress: 0.3 Ib/s.f.
Entrains: 15mm particle
31

s
32
Of RAnk
1 "=200'
3
0 200 400
NORTH CAROLINA
DEPARTMENT OF TRANSPORTATION
31
z o PROJECT DEVELOPMENT AND
ENVIRONMENTAL ANALYSIS BRANCH
n
Clayhill Farms
i Wetland & Stream Mitigation
31 Plan Report

i?
?32 f
31
Project #1960024-203.00 & 1960024-019.00
32
Feeder Ditches
As part of the proposed conditions, the existing feeder ditches will be blocked at each of their
downstream ends(Figure 12). All ditches will be blocked with earthen fill to within 0.5 feet of their top
of bank except ditches D-9, D-10 and D-11 (as identified in the DRAINMOD investigation, see Section
4.1.1) which will be blocked to grade. In order to determine the height of the peak flow rate at the
blocked downstream end of each ditch, the blocked ditches have been modeled under weir conditions.
The time of concentration for each individual area was revised to disregard the travel time within the ` - - --
individual ditches. During the peak flow rate conditions, the blocked ditches will be filled with storm
water runoff, and there will be negligible travel time in the filled ditch. Table 7 shows the adjusted
time of concentration, proposed flow rates (based on Rational method), head depth of weir, and head
depth above top of bank.
Table 7. Proposed conditions of feeder ditches.
2-Year Storm 10-Year Storm
Peak Flow Head Over Head Over Peak Flow Head Over Head Over
Ditch Rate , Weir , Top of Bank Rate , Weir , Top of Bank
# cfs) ; ft , ft cfs , ft , (ft)
1 18.9 , 0.7 , 0.2 24.4 , 0.9 , 0.4
2 19.0 ; 0.7 ; 0.2 24.7 ; 0.9 ; 0.4
3 12.9 ; 0.5 ; 0.0 17.5 ; 0.6 ; 0.1
4 13.5 ; 0.5 ; 0.0 17.4 ; 0.7 ; 0.2
5 14.4 ; 0.5 ; 0.0 18.6 ; 0.6 ; 0.1
6 21.5 ; 0.6 ; 0.1 28.3 ; 0.7 ; 0.2
7 11.5 ; 0.4 ; -0.1 15.1 ; 0.5 ; 0.0
8 17.6 , 0.5 , 0.0 22.8 i 0.6 , .01
9 7.0 ; 0.3 ; -0.2 9.0 ; 0.3 ; -0.2
10 5.5 ; 0.2 ; -0.3 7.2 , 0.2 ; -0.3
The table shows that the top of the bank at the downstream end of the ditches will be breached with
approximately zero to five inches of stormwater (head) during the peak duration of runoff. This
stormwater runoff will result in flooding the adjacent floodplain surrounding the ditches and will drain
into Billy's Branch using a new conveyance designed to accommodate these flows.
Billy's Branch
The proposed conditions of Billy's Branch were modeled using the HEC-2 program. The existing total
drainage area (971 acres) will not change, the peak time of concentration will not change, and the
overall runoff curve numbers will remain the same. The runoff curve numbers for the areas that are
being converted to wetlands will, over time, decrease under the proposed conditions. In order to be
conservative with the model and to represent the early conditions during their conversion to wetlands
(fallow fields), the existing curve numbers were used to generate the peak flow rates for the proposed
conditions. The existing tailwater condition of 22.7 feet at the culverts beneath SR 1101 will remain
the same for the proposed conditions of Billy's Branch. The HEC-2 model was revised to reflect the
NCDOT Clayhill Farms Wetland and Stream Mitigation Plan Report July 1999
Langley and McDonald, P. C, Nos. 1960024-203.00 and 1960024-019.00 Page 24
proposed longitudinal profile, stream length and cross-sections generated from the fluvial
geomorphological analysis. The proposed cross-sections were changed to reflect the smaller depth and
width of the proposed Billy's Branch (Figure 8) cross section based on the use of the regional curves
and data from the primary (off-site) reference reach.
Table 8 shows the peak flow rate, the top of bank elevation, and existing and proposed ditch conditions
of Billy's Branch. One result from the HEC-2 model was that it indicated a "hydraulic jump" between
nodes 4 and 5. This reflects an increase in velocity (energy) caused by valley slope increasing between
these nodes while the stream channel dimensions and sinuosity remain relatively constant and the
floodplain narrows. The resulting turbulent condition is a normal condition that generates rapids within
streams. Without further adjustments to the proposed stream, the condition would become erosive.
This issue will therefore be evaluated in detail and resolved during final design by either increasing
sinuosity, providing grade control (e.g. step pools), shoreline protection or some combination of these
solutions.
Table 8.
Proposed surface water profile of Billy's Branch.
Existing Conditions
Peak Stormwater Water Surface Peak Stormwater
Node # Runoff cfs , Elevation (ft) Runoff cfs)
7
6
5
4
3
2
1
323 , 22.7 323
176 ; 22.69 176
148 ; 24.57 148
143 ; 24.49 143
95 ; 31.81 95
73 ; 32.71 73
38 ; 32.94 38
4.1.5 Fooodplain Restoration
Proposed Conditions
Water Surface
Elevation (ft)
22.70
22.72
26.62
26.99
32.26
33.67
33.76
As mentioned earlier, the existing condition of Billy's Branch contains the peak flows from the two-
year storm within the stream's channel due to its depth and has therefore abandoned its floodplain. The
new floodplain generated by the proposed restoration of Billy's Branch is illustrated on Figure 12.
Between nodes 1 and 2, the proposed-stream will generate a floodplain approximately one foot higher
(Table 9) and 1,650 feet wider than existing conditions (Figure 12).
Node 3 will generate a floodplain 0.5 feet higher than existing conditions. The width of floodplain, 200
feet, while narrower than at nodes 1 and 2, fills the historic floodplain as evidenced by review of the
ortho-topographic mapping provided by the NCDOT (Figure 12).
The flood elevations increase sharply between nodes 4 and 5 to approximately 2.25 feet above existing
conditions, due to the constriction of the valley in this area. It is due to this constriction in the valley
width that the floodplain is only 25 feet wide, except at the confluence with the tributary to the north.
The floodplain of Billy's Branch extends 170 feet up the tributary.
NCDOT Clayhill Farms Wetland and Stream Mitigation Plan Report July 1999
Langley and McDonald, P. C, Nos. 1960024-203.00 and 1960024-019.00 Page 25
Table 9. Existing and proposed peak flood elevations.
Node # Existing Conditions (ft) Proposed Conditions (ft) Increase in Peak (ft)
1 32.9 33.8 0.9
2 32.7 33.7 1.0
3 31.8 32.3 0.5
4 24.5 27.0 2.5
5 24.6 26.6 2.0
6 22.7 22.7 0.0
7 22.7 22.7 0.0
The flood elevations and floodplain widths remain constant between nodes 6 and 7, an area where the
floodplain that is, on average, approximately 125 feet wide (Figure 12). Although the proposed stream
channel at node 6 is shallower and not as wide as the existing conditions, the floodplain is much wider
than at nodes 4 and 5 upstream, thus providing more storage without a rise in the storage elevation.
Node 7 is off-site and neither its cross-section nor slope can be altered. The flood elevation at node 7 is
the same under proposed conditions as it is in existing conditions which confirms that the channel,
meander and slope adjustments made within the Clayhill Farms property appears to have no deleterious
effect on downstream properties nor the culverts beneath SR 1101.
4.2 Conceptual Planting Plan
Natural communities are dependent primarily upon landscape position, soil type, and hydrology. The
first step in determining which natural communities likely occurred at Clayhill Farms was to find
natural areas with the same characteristics as Clayhill Farms (soil type, hydrology, and landscape
position). These areas were located through review of published references and conversations with Mr.
Richard LeBlond, Biologist with the N. C. Natural Heritage Program. Once these stands were
inventoried, the data obtained was compared to that in Classification of the Natural Communities of
North Carolina (Schafale and Weakley 1990). Combined with the data developed from the
groundwater and surface water analyses, this data is the basis for the proposed planting plan.
4.2.1 Reference Stands
Only two stands were identified which had the same physical characteristics as Clayhill Farms (Figure
1). Both were on the Croatan National Forest. Vegetation Reference Area 1 was located on a tributary
to Holston Creek approximately 1.7 miles northwest of Clayhill Farms. Vegetation Reference Area 2
was located at the off-site stream reference reach approximately 1.3 miles east of Clayhill Farms. The
soil types found at Clayhill Farms are not common in the vicinity of the site and locating reference
stands was difficult. All areas of Torhunta soil in the vicinity of Clayhill Farms have been converted to
agriculture or pine plantations. Pantego soil is similar to Torhunta and is located adjacent to Clayhill
Farms. However, as the adjacent forest is not in its natural state due to past high-grading, vegetation on
Pantego soil was investigated but not sampled (see Section 4.2.2 below). A sample plot was also not
NCDOT Clayhill Farms Wetland and Stream Mitigation Plan Report July 1999
Langley and McDonald, P. C., Nos. 1960024-203.00 and 1960024-019.00 Page 26
taken in the mesic pine flatwoods community investigated on Onslow soil because it has been burned
too frequently to possess characteristic vegetation.
A 50-foot diameter circular plot was taken on each soil type in each landscape position at both
Reference Areas. The diameter at breast height (dbh) of every stem larger than one inch in dbh was
measured and recorded, as was the percent cover (by species) of all species in the shrub and herbaceous
layers. In all six plots were sampled. Data from the sample plots are summarized in Table 10.
An Importance Value (IV) was calculated for each tree species in each plot as follows. First, the
density of all stems greater than one inch in dbh was determined for each species on a per acre basis.
For example, musclewood (Carpinus carolinana) in plot 4 had 14 stems that were one inch in dbh or
larger, therefore the stem density for musclewood is 311 stems per acre. Then, the basal are of each
tree species (based on all stems) was determined and expressed in square feet (ft2) of basal area per acre
(ac). The corresponding value of musclewood in plot 4 was 31.02 ftZ/ac. Next, all density and basal
area values within a plot were divided by the total density and basal area for all species in the plot to
derive the percentage of total density and basal area each species represented (thus the relativized
values for musclewood in plot 4 were 311/555 x 100 = 11.01% and 31.02/ 281.82 x 100 = 56.00% for
density and basal area respectively). The importance value for each tree species was determined by
averaging its relative density and relative basal area, yielding an IV of 33.50 for musclewood in plot 4.
Species with Importance Values greater than ten are listed in Table 10.
Table 10. Mean community characteristics for vegetation sample plots.
Stems per
Acre Basal Area
per Acre # of Species
per Plot % Hydrophytic
Species per Plot Species with
IV ? 10
swamp blackgum
musclewood
Coastal Plain American holly
Bottomland 658 238 6.3 84% water oak
Hardwood Forest sweetgum
sweet bay
bald cypress
loblolly pine
yellow-poplar
flowering dogwood
Mixed Mesic 322 210 6.5 57% musclewood
Hardwood Forest sweetgum
water oak
longleaf pine
4.2.2 Proposed Communities
Based on the data collected from the vegetation sample plots, Classification of the Natural
Communities of North Carolina (Schafale and Weakley 1990), and the hydrology modeling, it was
determined that a variety of communities likely occurred naturally on and around Clayhill Farms.
NCDOT Clayhill Farms Wetland and Stream Mitigation Plan Report July 1999
Langley and McDonald, P.C., Nos. 1960024-203.00 and 1960024-019.00 Page 27
Figure 14 depicts these communities and describes their landscape position, common tree species, and
typical soil type. Three of these communities are proposed for Clayhill Farms: non-riverine wet
hardwood forest (78.5 acres), mesic pine flatwoods (41.9 acres), and mixed mesic hardwood forest
(21.4 acres). Wetland hydrology will be enhanced in (1.8 acres) of a fourth community already
occurring at the site, coastal plain bottomland hardwood forest. The following sections detail each of
these communities and list the species proposed for planting in them. Figure 15 depicts the planting
zones for each of these communities.
Non-Riverine Wet Hardwood Forest
The forests on Pantego soil surrounding Clayhill Farms presently exist as a pond pine woodlands. As
pond pine woodlands typically occur on the edges of peatland communities, all but absent in the
vicinity of the property, it is unlikely these forests are in their natural condition. The Torhunta and
Pantego soils at Clayhill Farms most likely supported a non-riverine wet hardwood forest community
in their natural state.
Non-riverine wet hardwood forests occur on poorly drained interstream flats and are saturated part of
the year. Typically, these flats are or are near the highest parts of landscape. They are typically on
poorly drained loamy or clayey mineral soils and are almost always jurisdictional wetlands. At least
five of the following species should be planted on the Torhunta and Pantego soil: swamp chestnut oak
(Quercus michauxii, FACW-), laurel oak (Quercus laurifolia, FACW), cherrybark oak (Quercus
falcata var. pagodc?olia, FAC+), yellow-poplar (Liriodendron tulipifera, FAQ, American elm (Ulmus
americana, FACW), swamp blackgum (Nyssa sylvatica var. biflora, OBL), and American holly (Ilex
opaca, FAC-). Red maple (Acer rubrum, FAC) and sweetgum (Liquidambar styraciflua, FAC+) are
important components of non-riverine wet hardwood forests but are not recommended for planting as
they will likely regenerate naturally on the site from adjacent areas.
This area is expected to be saturated most of the year. As shown on Figure 15, approximately 30.1
acres of this community will be in the floodplain of the new stream and inundated during the two-year
storm for one to two days after the ditches are blocked and Billy's Branch is restored. Another 11.7
acres is projected by DRAINMOD to remain effectively drained (and thus not possess wetland
hydrology) as the southern perimeter ditch cannot be blocked (it is not completely owned by the
NCDOT). Hydrology monitoring wells are located within this area, and they may show this area of
upland buffer to be smaller than that suggested by the modeling.
Mesic Pine Flatwoods
Mesic pine flatwoods occur on flat to gently rolling areas which are neither excessively dry nor have a
significant seasonally high water table. In general, they are marginal wetlands. Mesic pine flatwoods
have an open to nearly closed canopy of longleaf pine (Pinus palustris) and pond pine (Pinus serotina)
with a diverse understory of hardwood trees. It is likely that most of the areas on Clayhill Farms
mapped in the soil survey as containing Onslow soils were this mixed pine community. Recommended
plantings for the Onslow portions of the site include only longleaf pine (FACU+) and pond pine
(FACW+). Approximately 11.1 acres of this community is expected to be upland buffer due either to
the presence of non-hydric soils or the drainage effect of the southern perimeter ditch. Approximately
NCDOT Clayhill Farms Wetland and Stream Mitigation Plan Report July 1999
Langley and McDonald, P. C., Nos. 1960024-203.00 and 1960024-019.00 Page 28
Pond Pine Non-riverine Wet Pine Mesic Pine Mixed Mesic Coastal Plain Coastal Plain
NATURAL
COMMUNITY
Woodland
Wet Hardwood
Flatwoods
Flatwoods
Hardwood Forest
Bottomiand
Small Stream

uent Fire)
(Infre Forest
(Infre
uent Fire) (Moderately
t Fir
F Moderately
uent Fire
?re
(Protected from Fire Hardwood Forest Swamp
? )
q q requen
e) )
q
pond pine swamp chestnut oak longleaf pine longleaf pine American beech laurel oak bald cypress
loblolly bay laurel oak pond pine pond pine yellow - poplar overcup oak swamp blackgum
CANOPY cherrybark oak so. sugar maple willow oak yellow - poplar
CODOMINANTS'I yellow poplar southern red oak white oak water oak red maple
sweet bay sweetgum water oak nor. red oak red maple laurel oak

loblolly pine
American elm post oak

blackjack oak
sweetgum
loblolly pine
overcup oak
red bay red maple bluejack oak swamp chestnut oak Atlantic white - cedar swamp chestnut oak
Atlantic white - cedar svlamp blackgum pale hickory cherrybark oak sweetgum river birch
musclewood mockernut hickory shagbark hickory American elm

UNDERSTORY
red maple sweetgum so. red oak loblolly pine

pond pine

TREES A
merican holly
paw paw
flowering dogwood
red maple
red bay
Y'"' d r tir" American holly
ironwood American holl
y musclewood

sourwood
sweet bay red maple

American holly

= ?? ! +I
'I F
-.2 N
+ musclewood
red maple, red bay sweet bay
red bay
titi

+ ? ?L ti, Y ;r ; S?`? K
1y.?
'
?
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Sy
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,
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fe>'
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?.Y

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I
Flat or gently rolling areas
LANDSCAPE Outer parts of domed Poorly drained interstream Flat or nearly flat that are neither North facing bluffs or Relatively high parts of Floodplain of small
peatlands on poorly flats saturated part of seasonally wet areas. excessively dry nor have ravines and upland the floodplain away blackwater streams
POSITION
drained interstream flats
the year
a significant seasonally
flats
from the channel of
high water table. I blackwater streams
Shallow histosols or I

SOIL TYPE oligotrophic mineral soils Poorly drained loamy of I Loamy or fine textured
Moist upland soils I Bottomland mineral

soils of various textures Alluvial or organic
9a

(example) with organic surface clayey mineral soils
T
h
t
P
t Wet, Sandy Spodosols
l
O soils, sometimes
d I
(Onslow/Marvyn) ,
often very sandy soils
layers or
un
a/
an
e o
( 9) ns
(
ow) san (Muckalee)
(Torhunta) (Onslow) (Muckalee)
-

Clayhill Farms Wetland

IGURE 14

OTE:

Exists on site
; DEPART ARDLI""
NORTH
i DEPARTMENT OF TRANSPORTATION
PROJECT DEVELOPMENT AND
and Stream Mitigation
Plan Report
LANDSCAPE PROFILE OF NATURAL COMMUNITIES - ,` Proposed for site ENVIRONMENTAL ANALYSIS BRANCH
and McDonald- P.C.
Langley .?...?Adapted from Schafale and Weakley, 1990.

n 17
Croatan
National
Forest
(2) 18' CMP
0
Project #1960024 203.00 & 1960024-019.00
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Croatan National Forest
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Wetland & Stream Mitigation
Plan Report
Figure 15
Proposed Planting Plan
Legend
Property Boundary
Non-Riverine Wet Hdwd
Forest Restoration
® Mesic Pine Flatwoods
Restoration
- Mixed Pine Regeneration
(Preservation)
(-; Mixed Mesic Hdwd Forest
Restoration
® Mixed Mesic Hdwd Forest
Preservation
- Bottomland Hdwd Forest
Enhancement
Bottomland Hdwd Forest
Preservation
IIIl
+Area of Non-Hydric Soil
Area Effectively Drained
After Restoration
,It
I
1"=500'
0 500 1000
NORTH CAROLINA
DEPARTMENT OF TRANSPORTATION
PROJECT DEVELOPMENT AND
ENVIRONMENTAL ANALYSIS BRANCH
Langley and McDonald, PC
E'I g?naes-Ruvovo's P?a"m
L-11C(}la AichiECt6 - EnviroamentaConsullanis
ww,vacyaaycom
III VRGINIA REACH wILLAMSBUIRU
2.2 acres of this community will be in the floodplain of the new stream after the ditches are blocked
and Billy's Branch is restored.
Mixed Mesic Hardwood Forest (Coastal Plain Subtype)
All of the Marvyn soil on Clayhill Farms and parts of the Onslow soil will be planted to reflect a mixed
mesic hardwood forest community. This community will occur primarily below the 31.0-foot contour
line on the eastern end of the site. Parts of this community may become jurisdictional wetlands over
time; however, due to the well drained nature of this soil most of it will remain simply as upland
riparian buffer. Only 5.6 acres of this community is expected to meet the soil and hydrology criteria
for jurisdictional wetlands. Mixed mesic hardwood forests typically occur on north-facing bluffs or
ravines on moist upland soils. This is the same landscape position that they will occupy at Clayhill
Farms. At least six of the following species should be planted in this area: yellow-poplar (FAC), water
oak (FAC), swamp chestnut oak (FACW-), cherrybark oak (FAC+), musclewood (FAC), laurel oak
(FACW), southern sugar maple (NI), and American beech (FACU). Sweetgum (FAC+) is an important
component of this community but is not recommended for planting as it will likely regenerate naturally
on the site from adjacent areas.
Coastal Plain Bottomland Hardwood Forest (Blackwater Subtype)
Coastal plain bottomland hardwood forests occur on the relatively high parts of the floodplain of
blackwater creeks and rivers. These portions of the floodplain are inundated in major flood events
(such as the ten-year storm) for as much as a day or two. They are saturated most, if not all, of the year
and are jurisdictional wetlands. They occur on bottomland mineral soils of various textures. At
Clayhill Farms, this community originally occurred on the northern side of Billy's Branch and along
the north-south tributary of Billy's Branch in the center of the property. As mentioned earlier, portions
of this community has been drained to the point that it no longer functions as a floodplain due to the
channelization of Billy's Branch. Approximately 1.8 acres of this community will be enhanced from
marginal wetlands to the original floodplain community by the restoration of Billy's Branch. No
additional plantings are recommended for this community.
5.0 SITE CONSTRUCTION AND PLANTING REQUIREMENTS
5.1 Site Construction
Site construction will include the following activities:
• Clearing and grading necessary to create new stream alignment between nodes 1 and 3;
• Filling the downstream ends of ditches 1 through 8 with clean earthen fill to 0.5 feet below
grade;
• Filling the downstream ends of ditches 9 through 11 with clean earthen fill to grade;
NCDOT Clayhill Farms Wetland and Stream Mitigation Plan Report July 1999
Langley and McDonald, P. C., Nos. 1960024-203.00 and 1960024-019.00 Page 29
• Providing minor C or E type tributaries downstream of all ditch blocks to convey flow from
fields into Billy's Branch;
• Creating a stable sinuosity and stream cross-section between nodes 3 and 6 (use of grade
control structures may be necessary between nodes 4 and 5);
• Filling abandoned stream channel where necessary using material from berm located along
southern bank of Billy's Branch, oxbow lakes (Rosgen 1999) and the borrow area located in
non-hydric soils (Figure 12);
• Installing a grade control structure at the downstream end of Billy's Branch to allow stable
transition to reach owned by Croatan National Forest; and
• Re-installing the 20 shallow groundwater monitoring wells presently on-site.
5.2 Site Preparation and Planting Requirements
It is recommended that the site be randomly shaped to establish irregular contours with high ridged
areas (no more than 12 inches above average grade) and depressional furrows (no more than 12 inches
below average grade). This will increase surface storage at the mitigation site, restore natural
microtopography to the site, and provide microsites for planting trees to reduce seedling mortally drde
to high water tables (McKinney and Shear 1997, Tweedy and Evans 1999). "Ripping" and disking of
the site will create this "roughing up" of the site as well as reduce the effects of former soil compaction.
No other site preparation is recommended prior to planting.
Bare root seedlings will be planted on eight-foot centers throughout the planting zones, resulting in 680
trees per acre. In hardwood dominated communities, no more than 20 percent of plantings will be of
any one species. Planting will occur outside of the growing season (i.e., between November and
March) to allow the plants to stabilize during the dormant season.
Areas disturbed for hydrologic restoration will be seeded with the NCDOT's standards erosion and
sedimentation control mix appropriate for wetland areas. The area will be overlain with a mulch
layer/mixture to facilitate germination, retain moisture, and further reduce erosion and sedimentation.
No seedlings are recommended for planting in these areas as most are already forested, and, as such,
the existing canopy will quickly re-close after disturbance.
6.0 SUCCESS CRITERIA
Success criteria for the vegetation will be met when:
(Dan reater than 50 percent of the dominant plant species (both planted and/or recruited) have
indicator status facultative or wetter;
NCDOT Clayhill Farms Wetland and Stream Mitigation Plan Report July 1999
Langley and McDonald, P. C., Nos. 1960024-203.00 and 1960024-019.00 Page 30
(2) At least 320 trees/acre of approved target species have survived for at least three years
(planted plus recruited individuals);
(3) At least 288 trees/acre of approved target species have survived for at least four years
(planted plus recruited individuals); and
(4) At least 260 trees/acre of approved target species have survived for at least five years
(planted plus recruited individuals).
Success criteria for wetland hydrology will be met when the site
characteristics necessary for a jurisdictional determination under the
Delineation Manual (1987).
6.0 MONITORING PLAN
is determined to possess the
Corps of Engineers Wetlan
The wetland mitigation area will be monitored for five years following construction or until all suc ss
criteria established for the site have been met, whichever is longer. The stream restoration area ill be
monitored for two years. The following sections detail how this data will be obtained.
6.1 Wetland Mitigation Monitoring
Vegetation and hydrology will be monitored in the wetland mitigation portion of the site. During the
first year after planting, planted species will be visually examined to evaluate the degree to which
seedlings are being overtopped by herbaceous species. Quantitative sampling will be performed
between August 1 and November 30 of each year for five years following construction or until the
vegetation success criteria have been met, whichever is longer. 50-foot by 50-foot square plots will be
established in each planting zone as follows:
Non-Riverine Wetland Hardwood Forest Restoration 6
Mesic Pine Flatwoods Restoration 5
Mixed Mesic Hardwood Forest Restoration 3
Vegetation sample plots will be proximal to hydrology monitoring wells wherever practical to assist in
correlating vegetation and hydrology parameters. In each plot, species composition and density will be
recorded. Photograph locations will be established for each plot. The reference points and the four
corners of each plot will be located using GPS and included in the "as-built" report for the mitigation
site. Any areas of the site visually observed to not be meeting the established success criteria will also
be noted.
Twenty (20) remote shallow groundwater monitoring wells will be maintained and periodically
downloaded until success criteria have been met. After all earthwork is completed for Billy's Branch,
Wells 1 through 18 will be re-installed in their present locations. Wells 19 and 20 will be relocated into
the area of coastal plain bottomland hardwood forest which is being enhanced by the stream restoration
NCDOT Clayhill Farms Wetland and Stream Mitigation Plan Report July 1999
Langley and McDonald, P. C., Nos. 1960024-203.00 and 1960024-019.00 Page 31
activities. While DRAINMOD results indicate that portions of the farm fields adjacent to the southern
perimeter ditch will not meet wetland hydrology criteria, data from the wells- in that area may prove
otherwise.
6.2 Stream Restoration Monitoring
Vegetation and channel/stream bank stability will be monitored for the stream restoration portion of the
site for two years. The NCDOT will establish photograph reference points at representative sections of
the stream. The reference points will be located using GPS and included in the "as-built" report for the
mitigation site. The NCDOT will implement quarterly visits over the first year after completion of the
mitigation work to ensure channel/stream bank stability. Photographs showing coverage and survival
of the vegetative material and channel/stream bank stability will be taken at the end of the first growing
season. Any remedial action necessary will be coordinated with the U.S. Army Corps of Engineers and
initiated in a timely fashion with consideration given to seasonal constraints. The monitoring period
may be extended if the stream restoration is not stabilizing.
6.4 Reporting
The site will be visually inspected after construction and planting, and an "as built" exhibit will be
prepared to include final elevations, species composition and numbers, well and sample plot locations,
and photopgraph reference points. This exhibit will be provided to the permitting agencies within 60
days of completion of all construction activities.
Monitoring reports will be submitted to the permitting agencies following each monitoring event.
Submitted reports will document the sample plot locations and monitoring well locations and will
include photographs taken at each plot and in problem areas. All data collected during the monitoring
event will be summarized, and it will be stated which plots are, or are not, meeting the established
success criteria to date. The acreage of successful and unsuccessful areas will also be estimated.
7.0 MITIGATION RATIOS

Mitigation ratios for wetland impacts are determined on a project-by-project basis by the NCDOT and
Interagency Representatives. In general, mitigation ratios follow those recommended by the
Environmental Protection Agency Region IV and are as follows for forested wetland mitigation
(USEPA 1991):
Restoration 2:1
Enhancement 4:1
Preservation 10:1
In general, no credit is given for restoration, enhancement, or preservation of upland buffer areas.
However, if it is demonstrated that these upland areas have a marked benefit on wildlife populations
and wetland functions at the mitigation site, some credit may be allowed for the upland areas (Bell
NCDOT Clayhill Farms Wetland and Stream Mitigation Plan Report July 1999
Langley and McDonald, P. C., Nos. 1960024-203.00 and 1960024-019.00 Page 32
1999). As the uplands at Clayhill Farms are part of the natural mosaic of the landscape, and not merely
adjacent buffer areas, it is recommended that a 15:1 blended ratio be given for the upland restoration
and preservation combined. It should also be noted that the mixed mesic hardwood forest being
restored is the same community which comprises high quality natural area in the Registered SNHA
Hunters Creek Upland Forest less than 1.0 mile upstream of the site.
Generally, stream restoration for permitted impacts by the NCDOT is required at a ratio of 2:1.
8.0 DISPENSATION OF PROPERTY
Clayhill Farms borders the Croatan National Forest to the west, north, and east. As such, the U. S.
Forest Service would be the preferred recipient of the land. Representatives for the Croatan Ranger
District have expressed an interest in accepting eventual ownership of the mitigation site and have
stated that they see no problems regarding such a transfer.
The NCDOT will retain ownership of the site until all mitigation activities are completed and the site is
determined to be successful. A conservation easement or other restrictive covenant will be established
for the property and recorded with the deed when transferred to the U. S. Forest Service to ensure that
the property is managed for the purpose of wetland mitigation in perpetuity.
9.0 CONCLUSIONS
The results of the wetland and stream restoration plan for the Clayhill Farms property were a product
of an integrated analytical approach that evaluated the site's soils, groundwater hydrology, surface
water hydrology and hydraulics, fluvial geomorphology, landscape position, vegetation and wildlife.
This analysis was further supported by analyzing the least disturbed plant communities endemic to the
region located in areas with the same landscape positions, soils and proposed hydrology as that of the
Clayhill Farms property. Stream restoration was based upon accepted procedures in fluvial
geomorphology and hydraulics and utilized stream gage data and reference streams.
The 355.60 acre Clayhill Farms property currently contains approximately 155.9 acres of forested
wetlands and 199.7 acres of non-wetlands (141.8 acres of Prior Converted cropland and 57.9 acres of
forested land). The proposed wetland mitigation plan provides for 97.7 acres of wetland restoration,
1.8 acres of wetland enhancement, 155.9 acres of wetland preservation, 44.1 acres of upland
restoration, and 57.9 acres of upland preservation (Table 11). If the proposed mitigation ratios are
accepted, Clayhill Farms can provide mitigation for 71.6 acres of wetland impacts.
The Clayhill Farms property also contains 6,170 linear feet of incised, straightened stream. The
proposed restoration plan will restore 7,410 linear feet of stream. This will be done utilizing priority
one methodologies, which calls for re-establishing the stream at an elevation which is compatible with
the abandoned floodplain. By doing so, the stream mitigation plan causes approximately 65 acres of
NCDOT Clayhill Farms Wetland and Stream Mitigation Plan Report July 1999
Langley and McDonald, P. C., Nos. 1960024-203.00 and 1960024-019.00 Page 33
floodplain to be re-established on-site by decreasing the width and depth of Billy's Branch and
increasing the sinuosity (decreasing the slope) of the stream.
Table 11. Compensatory mitigation provided by the Clayhill Farms property.
Total Mit. Mit.
Mitigation Type Acres Ratio Acres
Wetland Restoration (Agricultural Fields) 97.7 2:1 48.9
Mesic Pine Flatwoods 24.6
Non-Riverine Wet Hardwood Forest 67.5
Mixed Mesic Hardwood Forest 5.6
Wetland Enhancement (Forested) 1.8 4:1 0.5
C. Plain Bottomland Hardwood Forest 1.8
Wetland Preservation (Forested) 154.1 10:1 15.4
Mixed Pine Regeneration 148.5
Mixed Mesic Hardwood Forest 3.6
Coastal Plain Bottomland Hardwood Forest 2.0
Upland Buffer Restoration (Agricultural Fields) 44.1 15:1 2.9
Mesic Pine Flatwoods 17.3
Non-Riverine Wet Hardwood Forest 11.0
Mixed Mesic Hardwood Forest 15.8
Upland Buffer Preservation (Forested) 57.9 15:1 3.9
Mixed Pine Regeneration 45.3
Mixed Mesic Hardwood Forest 12.3
Coastal Plain Bottomland Hardwood Forest 0.3
Total Acres of Compensatory Mitigation 355.6 71.6
Linear Feet of Stream Restoration 7,410.0 2:1 3,705.0
Hydraulic analysis indicates that there should be no adverse affect of this stream restoration on
downstream properties. Current findings suggest that a berm (one foot high) may be needed along the
western boundary of the farm fields of the Clayhill Farms property to insure that the Croatan Nation
Forest property is not flooded. It appears the floodplain historically extended onto the lands of the
National Forest. For these reasons the NCDOT will request permission from representatives of the
National Forest to re-establish the historic floodplain off-site to that within the Clayhill Farms property.
If this cannot be achieved, the berm will be constructed.
Upon review of this report by State and Federal regulatory agencies, the NCDOT will organize a site
inspection to allow further analysis of the findings presented in this mitigation plan report. After the
State and Federal agencies provide comments on this report, the NCDOT will review, analyze and
NCDOT Clayhill Farms Wetland and Stream Mitigation Plan Report July 1999
Langley and McDonald, P.C., Nos. 1960024-203.00 and 1960024-019.00 Page 34
respond to those comments in a stand alone document and then proceed with wetland and stream
restoration design (100% design and specifications) for the Clayhill Farms property.
10.0 REFERENCES CITED
200-700, DRAINMOD, version 4.0/5.0, June 1994.
Baumer, O. and J. Rice. 1988. Methods to Predict soil input for DRAINMOD. ASAE Paper No. 88-
2564. ASAE, St. Joseph, MI.
Bell, Mike. 1999. Personal communication with Mike Bell, Environmental Specialist for the
Washington Field Office of the Wilmington District U.S. Army Corps of Engineers in May and
June 1999.
Bouwer, H. 1989. The Bouwer and Rice Slug Test - An Update: Groundwater, Vol. 27, No. 3. Pp. 304-
309.
Doty, C. W., R. O. Evans, H. J. Gibson, R. D. Hinson, and W. B. Williams. 1986. Agricultural Water
Table Management: A Guide for Eastern North Carolina. North Carolina State University,
Raleigh, NC.
Langley and McDonald, P.C. 1998. Wetland Mitigation Site Feasibility Study for the Clayhill Farms
Property. Prepared for the North Carolina Department of Transportation Planning and
Environmental Branch. NCDOT Consulting Project No. 96-LM-11.
Langley and McDonald, P.C. 1998. Highway 24 - Sections AA and AB Wetland Mitigation Site Search
Final Report. Prepared for the North Carolina Department of Transportation Planning and
Environmental Branch. NCDOT Consulting Project No. 96-LM-06.
Leopold, Luna B. 1994. A View of the River. Harvard University Press, Cambridge, MA.
McKinney, J. D. and T. H. Shear. 1997. Effects of Microtopography on the Natural Regeneration of
Prior-Converted Wetlands. Masters thesis submitted to the North Carolina State University
College of Forest Resources. Raleigh, NC.
N. C. Department of Natural Resources and Community Development. 1985. Geologic Map of North
Carolina. N. C. Department of Natural Resources and Community Development. Raleigh, NC.
Scale 1:500,000.
N. C. Wildlife Resources Commission. 1998. Draft Guidelines for Stream Relocation and Restoration
in North Carolina. N. C. Wildlife Resources Commission, Raleigh, NC.
Rosgen, Dave L. 1996. Applied River Morphology. Wildland Hydrology, Pagosa Springs, Colorado.
NCDOT Clayhill Farms Wetland and Stream Mitigation Plan Report July 1999
Langley and McDonald, P. C, Nos. 1960024-203.00 and 1960024-019.00 Page 35
Rosgen, Dave L. 1999. Personal Communication.
Rosgen, David L. 1997. A Geomorphological Approach to Restoration of Incised Rivers. Proceedings
of the Conference on Management of Landscapes Disturbed by Channel Incision.
Schafale and Weakley. 1990. Classification of the Natural Communities of North Carolina. Third
Approximation. N C. Natural Heritage Program, Raleigh, NC.
Skaggs, R. W. 1980. DRAINMOD Reference Report: Methods for Design and Evaluation of Drainage-
Water Management Systems for Soils with High Water Tables. USDA Soil Conservation
Service, GPO.
Soller, D. R. and H. H. Mills. 1991. The Geology of the Carolinas: Carolina Geological Society Fiftieth
Anniversary Volume. J. W. Horton, Jr., and V. A. Zullo, Eds. University of Tennessee Press,
Knoxville, TN.
Starpoint Software. 1998. Super Slug: Aquifer Slug Test Analysis for Windows 95/NT. Starpoint
Software.
U. S. Army Corps of Engineers. 1987. Wetland Delineation Manual. U. S. Army Corps of Engineers,
GPO.
U. S. Department of Agriculture. 1981. Soil Survey of Jones County, North Carolina. USDA Soil
Conservation Service, GPO.
U. S. Department of Agriculture. 1995. Hydric Soils of the United States. Third Edition. USDA, GPO.
U.S. Environmental Protection Agency Region IV. 1991. Draft Mitigation Banking Guidance.
Received from Kathy Mathews, U.S. Environmental Protection Agency Region IV as most
recent guidance in May 1999.
U.S. Geological Survey. 1984. Topographic Map of Hadnot Creek, N.C. USGS, GPO. Scale 1:24,000.
U.S. Geological Survey. 1988. Topographic Map of Stella, N.C. USGS, GPO. Scale 1:24,000.
U.S. Geological Survey. 1998. Water Resources Data, North Carolina, Water Year 1997, Volume I.
Surface-Water Data. USGS-WDR-NC-97-1. National Technical Information Center,
Springfield, VA.
NCDOT Clayhill Farms Wetland and Stream Mitigation Plan Report July 1999
Langley and McDonald, P.C., Nos. 1960024-203.00 and 1960024-019.00 Page 36
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DEPTH
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DESCRIPTION

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2.5Y 2.5/1 SANDY CLAY
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DARK GRAY
10YR 311 SANDY LOAM
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CLAYHILL FARMS
IN Langley and McDonald, P.C.
Engineers - Surveyors - Planners
Landscape Architects - Environmental Consultants
VIRGINIA BEACH WILLIAMSBURG
WELL No: DMW-2
PROJECT. 1960024-203.00
CLIENT: NCDOT
DATE DRILLED: 2/1/99
DRILLED BY: FISHBURNE DRILLING
DRILLING METHOD: 4.25" ID HSA
LOGGED BY. BCC
SOIL TYPE: ONSLOW
DEPTH
(FEET) LITHOLOGY COLOR
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BLACK
WATER LEVEL 4.88' BELOW TOP OF CASING
2.5Y 614 SANDY LOAM
LT. YELLOWISH
BROWN
2.5Y 6/4 SANDY LOAM
LT. YELLOWISH
BROWN
2.5Y 512 SANDY LOAM
GRAYISH
BROWN
10YR 5/1 SANDY LOAM
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Engineers - Surveyors - Planners
CLAYHILL FARMS Landscape Architects - Environmental Consultants
VIRGINIA BEACH WILLIAMSBURG
WELL No: DMW-3
PROJECT. 1960024-203.00
CLIENT. NCDOT iL
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DEPTH
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WATER LEVEL 4.88' BELOW TOP OF CASING
2.5Y 614 SANDY CLAY LOAM. BROWNISH YELLOW MOTTLES
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2.5Y 612 SANDY CLAY LOAM (10YR 6/8)
LT. BROWNISH
GRAY
7.5YR 512 LOAMY SAND
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7.5YR 711 SAND
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7.5YR 711 SAND
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7.5YR 711 SAND
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19 Langley and McDonald, PC,
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GRAYISH
BROWN
10YR 512 SANDY LOAM
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5GY 511 SANDY LOAM, INCREASING CLAY
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CLAYHILL FARMS
19 Langley and McDonald, PC.
Engineers - Surveyors - Planners
Landscape Architects - Environmental Consultants
VIRGINIA BEACH WILLIAMSBURG
WELL No: DMW-5
PROJECT. 1960024-203.00
CLIENT. NCDOT
DATE DRILLED: 2/2/99
DRILLED BY: FISHBURNE DRILLING
DRILLING METHOD: 4.25" ID HSA
LOGGED BY: BCC
SOIL TYPE: TORHUNTA
DEPTH
(FEET) LITHOLOGY
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COLOR
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10YR 2/1 SANDY LOAM, ROOTS
BLACK
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GRAY
WATER LEVEL: 4.43' BELOW TOP OF CASING
2.5Y 612 SANDY CLAY
LT. BROWNISH
GRAY
10YR 311 SANDY CLAY
VERY DARK
GRAY
7.5YR 512 LOAMY SAND
BROWN
2.5YR 2.511 SANDY LOAM
BLACK
10Y 511 SANDY CLAY, VERY DARK GRAY MOTTLES
GRAY (10Y 311)
5GY 511 CLAY
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CLAYHILL FARMS
19 Langley and McDonald, PC.
Engineers - Surveyors - Planners
Landscape Architects - Environmental Consultants
VIRGINIA BEACH WILLIAMSBURG
WELL No: DMW-6
PROJECT: 1960024-203.00
CLIENT: NCDOT
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GRAY
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BROWN
5GY 311 SANDY LOAM
DARK
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5GY 311 BOTTOM OF WELL AT 14 FEET
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CLAYHILL FARMS
Langley and McDonald, P.C.
Engineers - Surveyors - Planners
Landscape Architects - Environmental Consultants
VIRGINIA BEACH WILLIAMSBURG
WELL No: DMW-7
PROJECT 1960024-203.00
CLIENT. NCDOT a
DATE DRILLED: 2/2/99
DRILLED BY: FISHBURNE DRILLING w
DRILLING METHOD: 4.25" ID HSA 3.
LOGGED BY: BCC
SOIL TYPE: TORHUNTA
DEPTH
(FEET)
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COLOR
DESCRIPTION
10 YR 311 SANDY LOAM, FINE ROOTS
VERY DARK
GRAY
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LT. YELLOWISH MOTTLES (7.5Y 5/8)
BROWN
WATER LEVEL: 4.85' BELOW TOP OF
CASING.
2.5Y612 SANDY LOAM, LARGE INDISTINCT MOTTLES
LT BROWNISH (10YR 6/6)
GRAY
10YR 7/1 LOAMY SAND, MEDIUM INDISTINCT GRAY
LT. GRAY MOTTLES (N5/1)
10YR 7/1 LOAMY SAND, MEDIUM INDISTINCT GRAY
LT. GRAY MOTTLES (N5/1)
10YR 511 SANDY LOAM
GRAY
BOTTOM OF WELL AT 14 FEET
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19 Langley and McDonald, P.C.
Engineers - Surveyors - Planners
Landscape Architects - Environmental Consultants
VIRGINIA BEACH WILLIAMSBURG
WELL No: DMW-8
PROJECT: 1960024-203.00
CLIENT. NCDOT
DATE DRILLED: 2/2/99
DRILLED BY: FISHBURNE DRILLING
DRILLING METHOD: 4.25" ID HSA
LOGGED BY: BCC
SOIL TYPE: TORHUNTA
DEPTH
(FEET)
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LITHOLOGY COLOR
DESCRIPTION
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10YR 2/1
BLACK SANDY LOAM, ROOTS, VEGETATION
STATIC WATER LEVEL: 2.59' BELOW TOP OF
.Z. CASING.
10YR 511
GRAY SANDY LOAM
2.5Y 7l2 SANDY CLAY, FEW FINE MOTTLES, LARGE
LT GRAY ROOTS
10Y5/1 SANDY CLAY, LARGE ROOTS
---- = GRAY

---------------
5GY 5l1 SANDY LOAM
GREENISH
GRAY
5GY 511 SANDY LOAM
GREENISH
GRAY
BOTTOM OF WELL AT 14 FEET
GRADES TO SANDY CLAY
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SOIL BORING LOG
CLAYHILL FARMS
19 Langley and McDonald, PC.
Engineers - Surveyors - Planners
Landscape Architects - Environmental Consultants
VIRGINIA BEACH WILLIAMSBURG
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WELL No: DMW-9
PROJECT. 1960024-203.00
CLIENT: NCDOT
DATE DRILLED: 212/99
DRILLED BY: FISHBURNE DRILLING
DRILLING METHOD: 4.25" ID HSA
LOGGED BY: BCC
SOIL TYPE: MARVYN
DEPTH
(FEET) LITHOLOGY COLOR
TO i-- - --? 3/1
_-5

_-10
_-15
DESCRIPTION
10YR
V. DK. GRAY SANDY LOAM
.5 5 SANDY LOAM, FEW ROOTS, LARGE INDISTINCT
LT. LIVE BRN.
2.5Y 7/6 SANDY CLAY LOAM, FEW FINE ROOTS
YELLOW
2.5Y 7/2 SANDY LOAM, FINE INDISTINCT MOTTLES
LT.GRAY (10YR 6/6)
WATER LEVEL: 10.96" BELOW TOP OF
CASING.
INDISTINCT MOTTLES, EVENTUALLY ALL
ORANGE
SANDYLOAM
7.5YR 6/8 BOTTOM OF WELL AT 14 FEET
REDDISH SANDY CLAY LOAM, 7.5YR 7/1 MOTTLES
YELLOW
bUY 4/1 SANDY CLAY
DK. GREENISH
GRAY
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SOIL BORING LOG 19 Langley and McDonald, P.C.
CLAYHILL FARMS Engineers -Surveyors - Planners
Landscape Architects -Environmental Consultants
VIRGINIA BEACH WILLIAMSBURG
WELL No: DMW-10
PROJECT: 1960024-203.00
CLIENT: NCDOT a
a
DATE DRILLED: 2/2/99
DRILLED BY: FISHBURNE DRILLING w
DRILLING METHOD: 4.25" ID HSA
LOGGED BY: BCC
SOIL TYPE: MARVYN
DEPTH
(FEET)
TO
-5
_-10
_-15
DESCRIPTION
2.5Y 312
VOK
GRAYISH SANDY LOAM, ROOTS
.
BRN.
2.5Y 712 SANDY CLAY LOAM, MEDIUM INDISTINCT
LT. GRAY MOTTLES (10YR 2/2)
25Y 6/4 SANDY LOAM
LT. YELLOWISH
BROWN
10YR 6/6 SANDY CLAY LOAM
SMALL INDISTINCT
BROWNISH ,
MOTTLES (10YR 5/1)
YELLOW
STATIC WATER LEVEL: 10.96' BELOW TOP OF
CASING.
10YR6/6 CLAY, LIGHT GRAY, LARGE INDISTINCT
BROWNISH MOTTLES
YELLOW
SANDY CLAY LOAM
BOTTOM OF WELL AT 14 FEET
10YR6/6 SANDY LOAM
BROWNISH
YELLOW
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SOIL BORING LOG
CLAYHILL FARMS
19 Langley and McDonald, P.C.
Engineers - Surveyors - Planners
Landscape Architects - Environmental Consultants
VIRGINIA BEACH WILLIAMSBURG
LITHOLOGY COLOR
WELL No: DMW-11
PROJECT: 1960024-203.00
CLIENT: NCDOT
DATE DRILLED: 2/2/99
DRILLED BY: FISHBURNE DRILLING
DRILLING METHOD: 4.25" ID HSA
LOGGED BY: BCC
SOIL TYPE: MARVYN
DEPTH
(FEET) LITHOLOGY
TO
-5
_-10
-15
5YG 4/1 SANDY CLAY
DARK
GREENISH GRAY
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SOIL BORING LOG Langley and McDonald, PC.
Engineers - Surveyors - Planners
I U9 Landscape Architects - Environmental Consultants
CLAYHILL FARMS
VIRGINIA BEACH WILLIAMSBURG
COLOR
DESCRIPTION
10YR 2/2 SANDY LOAM, FEW ROOTS
VYDRK.BRN
2.5Y 6/4 SANDY CLAY LOAM
LT. YELLOWISH
- - BROWN
10YR6/4 SANDY CLAY, STRONG BROWN LARGE DISTINCT
LT. GRAY MOTTLES (7.5YR 5/8), FEW FINE ROOTS
LOAMY SAND
I
WATER LEVEL: 8.98' BELOW TOP OF
CASING.
SAND
l
10YR 6/6
SANDY CLAY LOAM
BROWNISH
YELLOW
BOTTOM OF WELL AT 14 FEET
WELL No: DMW-12
PROJECT- 1960024-203.00
CLIENT: NCDOT
DATE DRILLED: 2/2/99
DRILLED BY: FISHBURNE DRILLING
DRILLING METHOD: 4.25" ID HSA
LOGGED BY: BCC
SOIL TYPE: MUCKALEE
DEPTH
(FEET)
TO
LITHOLOGY COLOR
DESCRIPTION
_-5
_-10
_-15
- - - - - - 10YR2/1 BLK. ORGANIC LAYER
10YR2/1 BLK. LOAM, FINE ROOTS
10YR 412 SANDY LOAM, VERY DARK BROWN, MEDIUM
DARK GRAYISH DISTINCT MOTTLES
BROWN
WATER LEVEL: 6.16' BELOW TOP OF
CASING.
10YR 611 LOAMY SAND, LARGE DISTINCT GRAY

I GRAY MOTTLES (N 5/1)
10YR 611 SANDY CLAY
GRAY
10B 2.511 SANDY LOAM
BLUISH
BLACK
BOTTOM OF WELL AT 14 FEET
10B 2.511 LOAMY SAND
BLUISH
BLACK
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SOIL BORING LOG
CLAYHILL FARMS
Langley and McDonald, P.C.
Engineers - Surveyors - Planners
Landscape Architects - Environmental Consultants
VIRGINIA BEACH WILLIAMSBURG
WELL No: DMW-13
PROJECT: 1960024-203.00
CLIENT. NCDOT
DATE DRILLED: 2/2/99
DRILLED BY: FISHBURNE DRILLING
DRILLING METHOD: 4.25" ID HSA
LOGGED BY: BCC
SOIL TYPE: MARVYN
DEPTH
(FEET) LITHOLOGY
TO
COLOR
10YR 2/1
BLACK
10YR 2/2
VERY DARK
BROWN
DESCRIPTION
CLAY LOAM, FINE ROOTS
WATER LEVEL: 4.62' BELOW TOP OF
CASING.
CLAY LOAM
_-5
2.5Y 7/4
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10YR 5/1
GRAY
2.5Y 7/4
PALE YELLOW
I
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MANY ROOTS
LOAMY SAND
COURSE SAND LAYER
LOAMY SAND
BOTTOM OF WELL AT 14 FEET
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CLAYHILL FARMS
Langley and McDonald, P.C.
Engineers - Surveyors - Planners
Landscape Architects - Environmental Consultants
VIRGINIA BEACH WILLIAMSBURG
WELL No: DMW-14
PROJECT: 1960024-203.00
CLIENT: NCDOT Q
DATE DRILLED: 2/2/99 U
DRILLED BY: FISHBURNE DRILLING w
DRILLING METHOD: 4.25" ID HSA
LOGGED BY: BCC
SOIL TYPE: MARVYN
DE
(Fl
PTH
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- GRAY

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YELLOW
I
_-15
DESCRIPTION
ORGANIC LAYER
SANDY LOAM, OXIDIZED RHIZOSPHERE
LOAMY SAND
WATER LEVEL: 6.61' BELOW TOP OF
CASING.
COARSENING SAND COMPONENT
LOAMY SAND
BOTTOM OF WELL AT 14 FEET
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SOIL BORING LOG Langley and McDonald, P.C.
Engineers - Surveyors - Planners
CLAYI1ILL FARMS Landscape Architects - Environmental Consultants
1 19 VIRGINIA BEACH WILLIAMSBURG
WELL No: DMW-15
PROJECT- 1960024-203.00
CLIENT. NCDOT a
a
DATE DRILLED: 2/3/99
DRILLED BY: FISHBURNE DRILLING w
DRILLING METHOD: 4.25" ID HSA 3:
LOGGED BY: BCC
SOIL TYPE: PANTEGO
DE PTH
(F EET) LITHOLOGY COLOR

10YR 2/1
BLACK
10YR 5/2
GRAYISH
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5GY 4/1
E _ = DARK
GREENISH GRAY
-15
DESCRIPTION
SANDY LOAM, FINE ROOTS COMMON
SANDY CLAY LOAM, FEW FINE ROOTS
WATER LEVEL: 5.7' BELOW TOP OF
CASING.
GRADES TO LOAMY SAND
SANDY CLAY LOAM, VERY DARK GRAY, LARGE
INDISINCT MOTTLES
SANDY CLAY, LARGE INDISTINCT MOTTLES
(10B 3/1)
BOTTOM OF WELL AT 14 FEET
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SOIL BORING LOG
CLAYHILL FARMS
Langley and McDonald, P.C.
Engineers - Surveyors - Planners
U9 Landscape Architects - Environmental Consultants
VIRGINIA BEACH WILLIAMSBURG
WELL No: DMW-16
PROJECT: 1960024-203.00
CLIENT: NCDOT a
DATE DRILLED: 2/3/99
DRILLED BY: FISHBURNE DRILLING w
DRILLING METHOD: 4.25" ID HSA 3:
LOGGED BY: BCC
SOIL TYPE: PANTEGO
DEPTH
(FEET)
-0
_-5
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--15
LITHOLOGY COLOR
DESCRIPTION
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BLACK
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LT. YELLOWISH (10YR 6/8)
BROWN
STATIC WATER LEVEL: 4.46" BELOW TOP OF
CASING.
10YR 511 SANDY CLAY, LARGE INDISTINCT MOTTLES (10YR 6/8)
GRAY
7.5YR4/1 LOAMY SAND

j DARK GRAY
10GY 311 SANDY CLAY LOAM
DARK
GREENISH GRAY

I_--- BOTTOM OF WELL AT 14 FEET
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SOIL BORING LOG
CLAYHILL FARMS
19 Langley and McDonald, PC.
Engineers - Surveyors - Planners
Landscape Architects - Environmental Consultants
VIRGINIA BEACH WILLIAMSBURG
WELL No: DMW-17
PROJECT- 1960024-203.00
CLIENT. NCDOT
DATE DRILLED: 2/3199
DRILLED BY: FISHBURNE DRILLING
DRILLING METHOD: 4.25" ID HSA
LOGGED BY: BCC
SOIL TYPE: PANTEGO
DEPTH
(FEET) LITHOLOGY COLOR
0
10YR 211 BLK.
2 5Y 612
-5
LT. YELLOWISH
BROWN
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DARK GRAY
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GRAY
10G 4/1
DARK GREENISH
GRAY
N 511
GRAY
DESCRIPTION
LOAM
WATER LEVEL: 4.22" BELOW TOP OF
CASING.
SANDY LOAM, LARGE INDISTINCT COMMON
MOTTLES (10YR 6/8)
LOAMY SAND
LOAMY FINE SAND
SANDY CLAY
BOTTOM OF WELL AT 14 FEET
COURSESAND
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SOIL BORING LOG
CLAYHILL FARMS
Langley and McDonald, PC.
Engineers - Surveyors - Planners
Landscape Architects - Environmental Consultants
VIRGINIA BEACH WILLIAMSBURG
WELL No: DMW-18
PROJECT- 1960024-203.00
CLIENT: NCDOT
DATE DRILLED: 2/3/99
DRILLED BY: FISHBURNE DRILLING
DRILLING METHOD: 4.25" ID HSA
LOGGED BY: BCC
SOIL TYPE: ONSLOW
DEPTH
(FEET) LITHOLOGY COLOR
0
10YR 2/1 BLK.
10YR 5/2
GRAYISH
BROWN
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BROWN
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i,
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BROWN
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DESCRIPTION
LOAM
SANDY CLAY LOAM, BROWNISH YELLOW,
MEDIUM INDISTINCT MOTTLES (10YR 6/8)
WATER LEVEL: 6.01' BELOW TOP OF
CASING.
LOAMY SAND
LOAMY SAND, SOME DARK GRAY, LARGE
INDISTINCT MOTTLES (N 4/1)
BOTTOM OF WELL AT 14 FEET
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SOIL BORING LOG Langley and McDonald, P.C.
CLAYHILL FARMS Engineers -Surveyors -Planners
Landscape Architects - Environmental Consultants
VIRGINIA BEACH WILLIAMSBURG
WELL No: DMW-19
PROJECT: 1960024-203.00
CLIENT: NCDOT
DATE DRILLED: 2/3/99
DRILLED BY: FISHBURNE DRILLING
DRILLING METHOD: 4.25" ID HSA
LOGGED BY: BCC
SOIL TYPE: TORHUNTA
DE
(FI
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COLOR
Y
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BLACK
2.5Y 6/2
LT. BROWNISH
GRAY
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i
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GRAY
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WATER LEVEL: 4.16' BELOW TOP OF
CASING.
SANDY LOAM, VERY DARK GRAYISH BROWN,
LARGE INDISTINCT MOTTLES (10YR 3/2)
LOAMY SAND
SANDY CLAY LOAM
BOTTOM OF WELL AT 14 FEET
SANDY CLAY LOAM
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SOIL BORING LOG
CLAYHILL FARMS
19 Langley and McDonald, P.C.
Engineers - Surveyors - Planners
Landscape Architects - Environmental Consultants
VIRGINIA BEACH WILLIAMSBURG
WELL No: DMW-20
PROJECT- 1960024-203.00
CLIENT. NCDOT a.
DATE DRILLED: 2/3/99
DRILLED BY: FISHBURNE DRILLING w
DRILLING METHOD: 4.25" ID HSA 3:
LOGGED BY: BCC
SOIL TYPE: ONSLOW
:PTH
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-0
V
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COLOR
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BLACK
10YR 412
DARK GRAYISH
BROWN
2.5Y 5/2
GRAYISH
BROWN
2.5Y 612
LT. BROWNISH
GRAY
5Y 711
LT. GRAY
DESCRIPTION
LOAM, ROOTS COMMON
SANDY CLAY, YELLOWISH BROWN, SMALL
INDISTINCT MOTTLES
WATER LEVEL: 5.79' BELOW TOP OF
CASING.
LOAMY SAND
FINE MEDIUM SAND
BOTTOM OF WELL AT 14 FEET
SAND
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SOIL BORING LOG
CLAYHILL FARMS
19 Langley and McDonald, P.C.
Engineers - Surveyors - Planners
Landscape Architects - Environmental Consultants
VIRGINIA BEACH WILLIAMSBURG
4
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Appendix C. DRAINMOD Technical Appendix
Not included in Agency Review Copy.
Available from NCDOT Project Development & Environmental Analysis.
ED

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Appendix D. Surfacewater Hydrology Technical
Appendix
Not included in Agency Review Copy.
Available from NCDOT Project Development & Environmental Analysis.
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3

Vegetation Identified at Clayhill Farms
Acer rubrum ...........................................................................................................red maple
Aronia arbutifolia ......................................................................... .................red chokeberry
Arundinaria gigantea .................................................................... ........................ giant cane
Clethra alnifolia ............................................................................ ............ sweet pepperbush
Cornus alternifolia ........................................................................ alternate leaved dogwood
Cyrilla racemiflora ....................................................................... .................................... titi
Diospyros virginiana .................................................................... .......................persimmon
Drosera capillaris ......................................................................... .................... pink sundew
Euonymus americanus .................................................................. ............... strawberry bush
Gaylussacia frondosa .................................................................... ........... dwarf huckleberry
Gelsemium sempervirens .............................................................. .............yellow jessamine
Gordonia lasianthus ..................................................................... ..................... loblolly bay
flex coriacea .................................................................................. .......................... gallberry
Ilex glabra ..................................................................................... ........................... inkberry
Leucothoe axillaris ........................................................................ .......................dog hobble
Liquidambar styraciflua ............................................................... ........................ sweetgum
Liriodendron tulipifera ................................................................. .................. yellow-poplar
Lyonia lucida ................................................................................ .........................fetterbush
Magnolia virginiana ..................................................................... .........................sweet bay
Myrica cerifera ............................................................................. ...................... wax myrtle
Nyssa sylvatica var. biflora ........................................................... ............ swamp blackgum
Osmunda cinnamomea .................................................................. ................. cinnamon fern
Osmunda regalis ........................................................................... ......................... royal fern
Persea borbonia ............................................................................ .............................red bay
Pinus serotina ............................................................................... .........................pond pine
Pinus taeda .................................................................................... .................... loblolly pine
Polygala lutea ............................................................................... .............. orange milkwort
Polystichum acrosticoides ............................................................ ................. Christmas fern
Pteridium aquilinum ..................................................................... .....................bracken fern
Quercus nigra ............................................................................... ......................... water oak
Quercus marilandica .................................................................... .................. blackjack oak
Quercus phellos ............................................................................ .......................willow oak
Quercus stellata ............................................................................ ........................... post oak
Rhododendron atlanticum ............................................................. .................... dwarf azalea
Sambucus canadensis .................................................................... ........................ elderberry
Sassafras albidum ......................................................................... .......................... sassafras
Smilax bona-nox ............................................................................ ................. saw greenbrier
Smilax laurifolia ........................................................................... .......laurel-leaf greenbrier
Smilax rotundifolia ....................................................................... ......... common greenbrier
Symplocos tinctoria ............................................................................................... sweet leaf
Toxicodendron radicans .......................................................................................poison ivy
Utricularia sp ..................................................................................................... bladderwort
Vaccinium corymbosum ..........................................................................highbush blueberry
Viola sp ........................................................................................................................ violet
Vitis aestivalis ........................................................................................................ fox grape
Woodwardia areolata .................................................................................netted chain fern
Woodwardia virginica ............................................................................ Virginia chain fern
Wildlife Observed at Clayhill Farms
(from visual observation or indication of animals)
Agelaius phoeniceus ............................................................................ red-winged blackbird
Anolis carolinensis .......................................................................... .................... green anole
Buteo jamaicensis ........................................................................... ................. red-tail hawk
Canis domesticus ............................................................................ ........................ feral dog
Cardinalis cardinalis ...................................................................... .......................... cardinal
Cathartes aura ................................................................................ ................ turkey vulture
Chelydra serpentina ........................................................................ common snapping turtle
Chrysemys picta .............................................................................. ..... eastern painted turtle
Clemmys guttata .............................................................................. ..................spotted turtle
Cnemidophorus sexlineatus ............................................................ .......six-lined racerunner
Colinus virginianus ......................................................................... ...........:...bobwhite quail
Coluber constrictor ......................................................................... ...... northern black racer
Didelphis virginiana ....................................................................... .......... Virginia opossum
Elaphe guttata ................................................................................. ..................... corn snake
Elaphe obsoleta ............................................................................... ...............black rat snake
Eumeces fasciatus ........................................................................... ............. five-lined skink
Eumeces laticeps ............................................................................. ............ broadhead skink
Felis familiaris ................................................................................ .......................... feral cat
Lampropeltis getula ........................................................................ .......... eastern kingsnake
Melanerpes carolinus ...................................................................... . red-bellied woodpecker
Meleagris gallopavo ....................................................................... ............................ turkey
Odocoileus virginianus ................................................................... ............white-tailed deer
Opheodrys aestivus ......................................................................... ......... rough green snake
Picoides pubescens ......................................................................... ....... downy woodpecker
Procyon lotor .................................................................................. .......................... raccoon
Sceloporus undulatus ...................................................................... ..... northern fence lizard
Sciurus carolinensis ........................................................................ .................. gray squirrel
Sialia sialis ...................................................................................... ..........:. eastern blue bird
Sternotherus odoratus ..................................................................... ..... common musk turtle
Sylvilagus floridanus ....................................................................... . eastern cottontail rabbit
Thamnophis sirtalis ......................................................................... ....... eastern garter snake
Urocyon cinereoargenteus .............................................................. ......................... gray fox
Ursus americanus ........................................................................... ...................... black bear
Vulpes vulpes .................................................................................. ........................... red fox
Zenaida macroura ........................................................................... .............. mourning dove
4
FOREST MANAGEMENT PLAN
for the
CLAYHILL FARMS MITIGATION SITE
JONES COUNTY, NORTH CAROLINA
PREPARED FOR THE
NORTH CAROLINA DEPARTMENT OF TRANSPORTATION
Project Development & Environmental Analysis Branch
One South Wilmington Street
Raleigh, North Carolina 27611
Issued: September 2003
f ?
TABLE OF CONTENTS
1.0 SITE LOCATION & VICINITY .............................................................................................1
2.0 OBJECTIVES & METHODOLOGY ...................................................... ..............................1
4.0 PROPOSED MANAGEMENT GOALS & ACI TIVITIES ..................................................... 3
4.1 Prescribed Burning ............................................................................................................... 3
4.2 Thinning ............................................................................................................................... 4
4.3 Management Activity Schedule ........................................................................................... 4
5.0 REFERENCES ......................................................................................................................... 5
APPENDIX A. COMPLETE FOREST INVENTORY DATA
LIST OF TABLES AND FIGURES
(figures follow page)
Figure 1. Vicinity Map ................................................................................................................... 1
Figure 2. Forest Stand Map ............................................................................................................ 1
Figure 3. Burning Activities Map .................................................................................................. 4
Figure 4. Thinning Activities Map ................................................................................................. 4
Table 1. Forest inventory data for RCW-specific density parameters ........................................... 2
Clayhill Farms Forest Management Plan
N. C. Department of Transportation - Clayhill Farms Mitigation Site

August 2003
Page ii
1.0 SITE LOCATION & VICINITY
The North Carolina Department of Transportation (NCDOT) Clayhill Farms Mitigation Site is
located in southwestern Jones County, North Carolina on the Hadnot Creek, NC and Stella, NC
7.5" USGS topographic quadrangle (Figure 1, Vicinity Map). It is bordered to the north, east,
and west by the Croatan National Forest and the south and east by various privately owned
forested and residential parcels. The 355.60-acre property currently consists of approximately
214 acres of pine forest (a mixture of both loblolly pine (Pinus taeda) and pond pine (Pinus
serotina)) and ±141 acres of fallow agricultural fields.
2.0 OBJECTIVES & METHODOLOGY
A forest inventory was conducted on the Clayhill Farms site by Carolina Silvics, Inc. in August
2003 to quantify habitat suitability for the federally endangered red-cockaded woodpecker
(Picoides borealis) (RCW). The property was divided into seven inventory areas (stands)
delineated by roads, paths, canals, and/or management history (Figure 2, Forest Stand Map).
The inventory consisted of 47 measurement points located throughout the forested portion of the
property.
At each point, variable plots were measured using a 10-factor prism. The diameter at breast
height (DBH), total height, and species was recorded for each tree counted as "in." All "in" trees
were measured regardless of size or species. The distance to any borderline trees was measured
using a 75-foot logger's tape. DBH's were taken with tree calipers; a hypsometer was used to
measure height. At least one tree per measurement point was aged using an increment borer with
three years added to the number of rings at DBH to determine age. Additionally, a 1/500-acre
plot was established at each point to count the number of woody plants in the understory. The
complete inventory data can be found in Appendix A.
3.0 EXISTING RCW HABITAT CONDITIONS
Inventory data important to the management of RCWs are summarized in Table 1.
There are two types of habitat requirements for the RCW: nesting and foraging. Nesting habitat
requires the presence of suitable cavity trees. In general, the birds prefer open pine stands at
least 60 years of age. The stand may be even-aged or have clumps of older trees contained
within it (Henry 1989, p.6). Stands that have a dense hardwood understory are avoided. There is
currently no nesting habitat available at the Clayhill Farms site due to the young tree age (5 to
25) and the density of the hardwood understory and midstory.
Foraging habitat requires pines 10 inches or greater in DBH, with a minimum stand size of 10
acres and a minimum stand width of 5 chains (330 feet) (Henry 1989, p.6). Trees may be as
young as 25 years old as long as the minimum stand size limits are reached (USFWS 1992, p.2).
As with nesting habitat, an open understory is preferred. Young pine stands cannot be
Clayhill Farms Forest Management Plan August 2003
N. C. Department of Transportation - Clayhill Farms Mitigation Site Page 1
Table 1. Forest inventor data for RU W -specific density arameters.
Overstor & Midstor Wood Understor
Average Stems Most
Stand Pine Hardwood Total Age per acre Common Spp.
TPA <10" 29 273 302
1 TPA>=10" 67 7 74 22 4,250 red maple
BA <10" 10 22.5 32.5
BA>=10" 50 0 5
TPA <10" 32 752 784
2 TPA>=10" 62 0 62 23 5,667 sweetgum
BA <10" 3 30 33 ink berry
BA>=10" 47 0 47
TPA <10" 81 116 197
3 TPA>=10" 42 0 42 22 6,000 sweetgum
BA <10" 16 10 26 red maple
BA>=10" 32 0 32
TPA <10" 165 42 207
sweetgum
4 TPA>=10" 65 0 65 25 9,500 red maple
"
BA <10 48 4 52
wax myrtle
BA>=10" 44 0 44
TPA <10" 85 7 92
5 TPA>=10" 71 5 76 23 4,400 sweetgum
BA <10" 26 2 28 ink berry
BA>=10" 48 2 0
TPA <10" 134 60 194
sweetgum
6 TPA>=10" 67 0 67 23 4,750 ink berry
<10"
BA 36 10 46
red maple
BA>=10" 43 0 43
TPA <10" 118 70 188
sweetgum
7 TPA>=10" 53 1 54 25 7,055 ink berry
"
BA <10 31 9 40
red maple
BA>=10" 34 1 35
*TPA = trees per acre BA = basal area
considered foraging habitat unless `opened up' by controlling the under- and mid-story
hardwoods with techniques such as thinning and burning (Henry 1989, p.6; USFWS 1992, p.6).
Approximately 43 acres of the Clayhill Farms site have been thinned by removing pine
pulpwood from the overstory (stands 1, 2, and 3 - Figure 2, Forest Stand Map). These stands
have a larger percentage of stocking with pines 10 inches or greater than the unthinned stands
(stands 4 through 7); however, there is no evidence that the hardwoods have been controlled,
and, as such, they exhibit the dense understory characteristics that RCWs avoid. All of the
forested areas at the Clayhill site have a significant component of pines that meet the size
and stocking requirements for foraging habitat.
Clayhill Farms Forest Management Plan August 2003
NC. Department of Transportation - Clayhill Farms Mitigation Site Page 2
It is believed that a colony of RCWs requires a contiguous habitat with at least 6,350 pine stems
of 10-inches DBH or greater and with a total pine basal area of 8,490 square feet (sq.ft.)
(USFWS 1985, p.19; Henry 1989, p.7). Clayhill Farms contains a contiguous pine forest with
approximately 10,000 pine stems over 10 inches DBH and 11,000 sq.ft. of pine basal area. The
foraging range for birds in a colony site is given as 0.5 miles (Henry 1989, p.7). At its widest,
the forested portion of Clayhill Farms is about 2700 feet, or 0.51 miles, wide. If suitable nesting
habitat is available on adjacent land,.birds should be able to utilize part or all of any suitable
foraging habitat provided on the Clayhill Farms property. In the process of conducting the forest
inventory, the path along the property line shared with the Croatan National Forest was traveled
by all-terrain vehicle (ATV). Portions of the national forest adjoining the Clayhill property
appeared to contain suitable nesting habitat characterized by large pines with an open understory.
Since there is currently no suitable nesting habitat on Clayhill Farms, the best prospect for use by
RCWs is to provide a high quality foraging habitat for any birds nesting on adjacent property.
4.0 PROPOSED MANAGEMENT GOALS & ACITIVITIES
Prescribed burning and thinning should provide high quality foraging habitat in 2 to 3 years.
Time will provide the required nesting habitat. In about 35 years, the current trees will old
enough to be utilized for cavity trees. In addition, the current young pine regeneration and any
pine planted as part of restoration activities will provide additional foraging habitat. To
maximize RCW habitat potential on newly planted pine areas in the wetland restoration area,
these areas should be located no further than 300 feet away from existing pine stands. In
addition, they should be at least 10 acres in size and 5 chains (330 feet) wide. RCWs will utilize
pond, longleaf (Pinus palustris), or loblolly pines. Of these three species, longleaf pine is the
most tolerant to frequent burning, especially at a young age. Growth time to 10 inches DBH
may be shortened by silvicultural techniques such as chemical weed control and fertilization.
4.1 Prescribed Burning
Since adequate pine stocking is currently available at the site, the most pressing course of action
is to control the midstory and understory hardwoods by prescribed burning. Burning should
begin as soon as possible and continue yearly until the hardwoods are controlled. If there is
adequate fuel to burn every year, this should be done for 2 or 3 years. Once the understory is
controlled, burning should continue at 2 to 3 year intervals in perpetuity.
Creation of a burning plan is recommended. A burning plan will identify any smoke sensitive
areas off property, specify appropriate weather parameters such as wind speed and direction, and
address any other issues such as problem soils. The burning plan will also set guidelines for
evaluation of burning success and specific timing for subsequent burns.
Fire line maintenance will not be difficult due to the presence of old roads and paths around and
through the property. A bulldozer may be required to initially install fire lines adjacent to the
cutover stream corridor and young pine regeneration. An agricultural type tractor can be used to
disk the fire lines prior to burning. Figure 3 shows the proposed locations of fire lines. Pine
regeneration in the recently clear-cut areas and the wetland restoration area (currently fallow
Clayhill Farms Forest Management Plan August 2003
N. C. Department of Transportation - Clayhill Farms Mitigation Site Page 3
agricultural fields) should be protected from fire until they are big enough to include in the
burning program (about age 15).
In addition to controlling hardwoods, prescribed burning reduces the risk of wildfire by lowering
the amount of fuel on the tract. Creation of the above-described fire lines on the property and
semi-annual prescribed burning should eliminate any wildfire concerns on the property. Also,
other animal species such as northern bobwhite quail (Colinus virginianus) and wild turkey
(Meleagris gallopara) will benefit from periodic burning.
4.2 Thinning
Some parts of Clayhill Farms can be commercially thinned (Figure 4). Stands 4, 5, and 6 are
especially suited to this due to a high percentage of upland soils (Langley & McDonald, PC
1999, Section 3.3). Pines less than 10 inches DBH and all merchantable hardwoods should be
removed. In these three stands, if only pines greater than 10-inches DBH are left, the stands will
have 44, 48, and 43 sq.ft. respectively, of basal area remaining in suitable RCW trees. This will
reduce the total pine basal area for the property to about 9,100 sq.ft., still above the target of
8,490 sq.ft. Thinning is not recommended in stands 1, 2 or 3 due to the prevalence of wetlands
soils in these stands, nor is it recommended for stand 7, as this stand currently has a low overall
basal area and only 34 sq.ft. of pines greater than or equal to 10 inches DBH.
The logging contractor should be made aware of the size limitations before beginning work so
that removal of 10-inch or greater DBH pines can be minimized. If desired, the trees not to be
harvested can be marked with paint. Typically, trees are marked at ground level with a spot of
paint and at DBH with a band of paint encircling the tree. This allows the equipment operator to
easily identify which trees not to cut, and also allows identification of stumps of trees which are
mistakenly harvested.
Road work should be allowed in order to facilitate the logging operation, including periodic
mowing of the interior road. This will also maintain the interior road as a fire break. Logging
decks should be allowed as needed and left up to the logging contractor. These small areas will
have only an insignificant impact on the RCW habitat. In addition, conveniently placed decks
lead to shorter and fewer skid trails, thereby reducing rutting and soil compaction.
4.3 Management Activity Schedule
Year 1(post-completion of wetland/stream monitoring)
Create a burning plan
Establish fire lines in accordance with plan
Maintain/repair interior logging road
Acquire a thinning contractor/contract
Mark trees for thinning
Thin and burn as weather conditions allow
Coordinate management activities with adjacent landowners
Clayhill Farms Forest Management Plan August 2003
N.C. Department of Transportation - Clayhill Farms Mitigation Site Page 4

Years 2 (post-completion of wetland/stream monitoring) and subsequent
Burn as per schedule established in burning plan
Year 15 (post-completion of wetland/stream monitoring)
Evaluate young pines for potential thinning and entry into burning program
Re-asses management plan and adjust as conditions dictate
5.0 REFERENCES
Henry, V.G. 1989. Guidelines for Preparation of Biological Assessments and Evaluations for
the Red-cockaded Woodpecker. U.S. Fish and Wildlife Service Southeast Region, Atlanta,
Georgia.
Langley and McDonald, P.C. 1999. Wetland and Stream Mitigation Plan for the Clayhill Farms
Property. Report prepared for the N.C. Department of Transportation Project Development
and Environmental Analysis Branch, Raleigh, North Carolina.
U.S. Fish and Wildlife Service (USFWS). 1985. Red-cockaded Woodpecker Recovery Plan.
U.S. Fish and Wildlife Service, Atlanta, Georgia.
U.S. Fish and Wildlife Service (USFWS). 1992. Draft Red-cockaded Woodpecker Procedures
Manual for Private Lands. Memorandum from U.S. Fish and Wildlife Service Southeast
Regional Director to All Southeast Region Field Supervisors and Refuge Managers.
Clayhill Farms Forest Management Plan
N. C. Department of Transportation - Clayhill Farms Mitigation Site
August 2003
Page 5
DEPARTMENT OF THE ARMY
WILMINGTON DISTRICT, CORPS OF ENGINEERS
P.O. BOX 1890
WILMINGTON, NORTH CAROLINA 28402-1890
IN REPLY REFER TO
May 22, 2001
Regulatory Division
Action ID No. 200100746, Clayhill Frams Mitigation Bank 2
4
SEE DISTRIBUTION
Dear Colleague:
This correspondence is in reference to the Clayhill Frams Mitigation Bank that is being
developed by the North Carolina Department of Transportation (NCDOT), located in
southwestern Jones County, North Carolina. The purpose of this letter is to formally establish
the Mitigation Bank Review Team (MBRT) for this project.
Pursuant to 60 FR 228, p.58610, paragraph 3., Agency Roles and Coordination,
collectively, the signatory agencies to the banking instrument will comprise the Mitigation Bank
Review Team. Representatives from the U.S. Army Corps of Engineers (CE), U.S.
Environmental Protection Agency (EPA), U.S. Fish and Wildlife Service (FWS), National
Marine Fisheries Service (NMFS), and the Natural Resources Conservation Service (MRCS), as
appropriate given the projected use of the bank, should typically comprise the MBRT. In
addition, it is appropriate for representatives from State, tribal and local regulatory and resource
agencies to participate where an agency has authorities and/or mandates directly affecting or
affected by the establishment, use or operation of a bank. This may include the North Carolina
Division of Water Quality (DWQ), Division of Coastal Management (DCM), and the Wildlife
Resources Commission (WRC).
In this regard, we are inviting your agency to join the MBRT for this mitigation bank.
If you wish to participate as a member of this MBRT, you should designate a specific
representative of your agency to serve on the MBRT and notify us in writing within 30 days of
your receipt of this letter.
Thank you for your time and cooperation. If you have any questions, please contact
Mr. Dave Timpy, Wilmington Regulatory Field Office, telephone [phone].
Sincerely,

E. David Franklin
Chi,4. i'?CDOT Team
1
DISTRIBUTION:
Mr. William L. Cox, Chief
Wetlands Regulatory Section - Region IV
Wetlands, Oceans, and Watersheds Branch
U.S. Environmental Protection Agency
Atlanta Federal Center
100 Alabama Street, S.W.
Atlanta, Georgia 30303
Mr. Garland Pardue
U.S. Fish and Wildlife Service
Fish and Wildlife Enhancement
Post Office Box 33726
Raleigh, North Carolina 27636-3726
Mr. David Rackley
NMFS
NOAA
219 Fort Johnson Road
Charleston, South Carolina 29412-9110
Mr. Ron Sechler
National Marine Fisheries Service
Pivers Island
Beaufort, North Carolina 28516
Mr. John Dorney
NCDENR-DWQ
Wetlands Section
1621 Mail Service Center
- Raleigh, NC 27699-1621
Mr. Doug Huggett
Division of Coastal Management
North Carolina Department of Environment,
Health, and Natural Resources
Post Office Box 27687
Raleigh, North Carolina 28557-7687
2
Mr. Frank McBride
North Carolina Wildlife Resources
Commission
Post Office Box 118
Northside, North Carolina 27564
Mr. Matthew R. Flint, State Biologist
U.S. Department of Agriculture
Natural Resources Conservation Service
4405 Bland Road, Suite 205
Raleigh, North Carolina 27609
DEPARTMENT OF THE ARMY
WILMINGTON DISTRICT, CORPS OF ENGINEERS
P.O. BOX 1890
WILMINGTON, NORTH CAROLINA 28402-1890
IN REPLY REFER TO September 18, 2001
Regulatory Division
Action ID No. 200100746, Clayhill Farms Mitigation Bank
See Distribution

Dear Colleague:
This correspondence is in reference t e Clayhill Farms Mitigation Ba that is being
developed by the North Carolina Departme ""- ated in Jones
County, North Carolina. Also, reference the final mitigation plan for this Bank dated July 1999.
As a member of the Mitigation Bank Review Team (MBRT), you are invited to attend a
meeting on Wednesday, October 24, 2001 at the Clayhill Farms Mitigation Site located on NC 58
in Jones County, North Carolina (map enclosed). Please meet at the intersection of NC 58 and
SR 1100 at 10:00 am. The purpose of the meeting is to discuss the Clayhill Farms Mitigation
Bank Prospectus, inspect the mitigation site, review the sixty-percent design plans, and address
any questions regarding the technical details of this proposal. Please review the final mitigation
plan and prospectus for this Bank prior to this meeting. Should you need additional copies of
these documents please advise.
Thank you for your time and cooperation. If you have any questions, please contact
Mr. Dave Timpy, Wilmington Regulatory Field Office, telephone [phone].
Sincerely,
E. David Franklin i
NCDOT Team Leader'
Distribution (with enclosure):
Mrs. Kathy Matthews
U.S. Environmental Protection Agency
980 College Station Road
Athens, Georgia 30605
t
a
Mr. Tom McCartney
U.S. Fish and Wildlife Service
Fish and Wildlife Enhancement
Post Office Box 33726
Raleigh, North Carolina 27636-3726
Mrs. Kelly Williams
Division of Coastal Management
North Carolina Department of Environment,
Health, and Natural Resources
Post Office Box 27687
Raleigh, North Carolina 28557-7687
Mr. Bennett Wynne
NC Wildlife Resources Commission
901 Laroque Avenue
Kinston, NC 28501
Mr. Mac Haupt
North Carolina Wetland Restoration Program
1619 Mail Service Center
Raleigh, NC 27699-1619
Mr. Phillip Todd
Project Development & Environmental
Analysis Branch
NC Department of Transportation
1548 Mail Service Center
Raleigh, N.C. 27699-1548
Mr. John Dorney
NCDENR-DWQ
Wetlands Section
1621 Mail Service Center
Raleigh, NC 27699-1621
2
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RE: Clayhill Farms -- management plan imap://[e-mail]:143/f...
Subject: RE: Clayhill Farms -- management plan
From: "Timpy, David L SAW" <[e-mail]>
Date: Mon, 29 Dec 2003 09:57:24 -0600
To: "'[e-mail]"' <[e-mail]>, "Timpy, David L SAW"
<[e-mail]>, Gary Jordan <[e-mail]>, Travis Wilson
<[e-mail]>, Chris Militscher
<[e-mail]>, John Hennessy <[e-mail]>
CC: Byron Moore <bgmoore @dot. state.nc.us>
Phillip,
December 29, 2003
Our comments on the Clay Hill Farms Mitigation Site Forestry Management Plan dated September 2003 as
requested in your email dated November 10, 2003 are summarized below:
1. The plan should address any potential impacts that activities to carry out the plan may have on the restored,
enhanced, or preserved wetlands and streams on the site. The approved mitigation plan should be referenced and
used to determine appropriate long-term management strategies, including creation of RCW habitat.
2. The plan should provide additional details of all management activities, particularly the establishment of fire
lines that may impact wetlands and streams on the site or have any adverse effects on adjacent properties such as
hydraulic trespassing. Please note that any adverse impacts on jurisdictional wetlands and streams that may result
from forestry management activities are not authorized.
3. The plan should reference the "Long Term Management Plan" for the site and be consistent with that plan as
well as the approved mitigation plan.
4. Site monitoring activities extend to five years from the completion of construction (100%) in accordance with
the approved mitigation plan. This does not appear to be consistent with the 15-year monitoring program indicated
on Page 5 of the plan and should be revised to reflect the approved mitigation plan (i.e. 5 years). Long term
management requirements are normally established in the long-term management plan and should not require
submittal of monitoring information beyond five years provided the site meets the mitigation plan requirements l
including the established success criteria.
I recommend that the subject plan be revised and distributed to the resource agencies for final comment.
6. Lastly, all activities on the Clay Hill Farms Mitigation Site must be consistent with the goals established by the
approved mitigation plan. Any work on this site must be in compliance with the approved mitigation plan, in
perpetuity.
Dave Timpy
1 of 2 1/14/2004 11:08 AM
RE: Clayhill Farms -- management plan imap://[e-mail]:143/f...
-----Original Message-----
From: [e-mail] [mailto:ptodd @dot. state.nc.us]
Sent: Monday, November 10, 2003 10:29 AM
To: Dave Timpy; Gary Jordan; Travis Wilson; Chris Militscher; John
Hennessy
Cc: Byron Moore
Subject: Clayhill Farms -- management plan
Attached is the revised draft management plan for the Clayhill
Farms Mitigation Site in Jones County. As you recall, we
distributed maps to the agencies at the meeting in Aug 2003.
Please review this information and provide comments to me by
December 19, 2003. Even if you do not have any comments, please
provide me with an email stating this.
If there are any questions, please let me know.
Philllip
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