20160919 Ver 1_401 Application_20160916

o�oF w A rERo�
Office Use Only:
Corps action ID no.
DWQ project no.
Form Version 1.3 Dec 10 2008
Page 1 of 11
PCN Form — Version 1.3 December 10, 2008 Version
Pre -Construction Notification PCN Form
A. Applicant Information
1.
Processing
1 a. Type(s) of approval sought from the
Corps:
®Section 404 Permit El Section 10 Permit
1b.
Specify Nationwide Permit (NWP) number: NW - 27 or General Permit (GP) number:
1 c.
Has the NWP or GP number been verified by the Corps?
® Yes
❑ No
1d. Type(s) of approval sought from the DWQ (check all that apply):
® 401 Water Quality Certification — Regular ❑ Non -404 Jurisdictional General Permit
❑ 401 Water Quality Certification — Express ❑ Riparian Buffer Authorization
1 e.
Is this notification solely for the record
because written approval is not required?
For the record only for DWQ 401
Certification:
❑ Yes ® No
For the record only for Corps Permit:
❑ Yes ® No
1f.
Is payment into a mitigation bank or in -lieu fee program proposed for mitigation
of impacts? If so, attach the acceptance letter from mitigation bank or in -lieu
fee program.
❑ Yes
® No
1 g.
Is the project located in any of NC's twenty coastal counties. If yes, answer 1 h
below.
❑ Yes
® No
1 h.
Is the project located within a NC DCM Area of Environmental Concern (AEC)?
❑ Yes
® No
2.
Project Information
2a.
Name of project:
Big Creek IV Stream Restoration
2b.
County:
Stokes
2c.
Nearest municipality / town:
Mount Airy
2d.
Subdivision name:
NA
2e.
NCDOT only, T.I.P. or state
project no:
3.
Owner Information
3a.
Name(s) on Recorded Deed:
See attached Property Owners Information
3b.
Deed Book and Page No.
3c.
Responsible Party (for LLC if
applicable):
3d.
Street address:
3e.
City, state, zip:
3f.
Telephone no.:
3g.
Fax no.:
3h.
Email address:
Page 1 of 11
PCN Form — Version 1.3 December 10, 2008 Version

4.
Applicant Information (if different from owner)
4a.
Applicant is:
® Agent ❑ Other, specify:
4b.
Name:
Rocky Powell
4c.
Business name
(if applicable):
Clear Creeks Consulting
4d.
Street address:
1317 Knopp Road
4e.
City, state, zip:
Jarrettsville, MD 21084
4f.
Telephone no.:
[phone]
4g.
Fax no.:
4h.
Email address:
[e-mail]
5.
Agent/Consultant Information (if applicable)
5a.
Name:
Rocky Powell
5b.
Business name
(if applicable):
Clear Creeks Consulting
5c.
Street address:
1317 Knopp Road
5d.
City, state, zip:
Jarrettsville, MD 21084
5e.
Telephone no.:
[phone]
5f.
Fax no.:
Same as above
5g.
Email address:
[e-mail]
Page 2 of 11
PCN Form — Version 1.3 December 10, 2008 Version

B.
Project Information and Prior Project History
1.
Property Identification
1a.
Property identification no. (tax PIN or parcel ID):
2002E/0154, 0495/1226, 00203/0793, 00495/1220
Latitude: 36°26.232 N
1 b.
Site coordinates (in decimal degrees):
Longitude: - 80°54.696 W
(DD.DDDDDD) (-DD.DDDDDD)
1 c.
Property size:
498 acres
2.
Surface Waters
2a.
Name of nearest body of water (stream, river, etc.) to
Dan River
proposed project:
2b.
Water Quality Classification of nearest receiving water:
C, Tr
2c.
River basin:
Roanoke River
3.
Project Description
3a.
Describe the existing conditions on the site and the general land use in the vicinity of the project at the time of this
application:
The dominant land use in the watershed is forest and agriculture. The project site is agriculture — cultivated land and large
wood lots.
3b.
List the total estimated acreage of all existing wetlands on the property:
0.0 acres
3c.
List the total estimated linear feet of all existing streams (intermittent and perennial) on the property:
10,000
3d.
Explain the purpose of the proposed project:
Correct the stream channel instability problems, improve water quality, enhance in -stream habitat, and restore natural
floodplain functions by implementing an effective, long-term restoration plan for the streams within the properties.
3e.
Describe the overall project in detail, including the type of equipment to be used:
IThe general restoration approach includes reconstructing reaches of Big Creek by stabilizing eroding streambanks,
reconnecting the channel with the floodplain, providing a more regular plan form along reaches where meander bends
are extremely tight, and modifying channel cross-sections to improve habitat and sediment transport capacity. The
majority of the fill placed will involve backfilling to narrow the existing overwide channel by constructing toe benches along
the channel margins to improve habitat and sediment transport. Toe wood will be installed along the outside of meander
bends to stabilize newly constructed banks and provide submerged habitat. In addition, log -boulder j -hooks, cross vanes
and constructed riffles will be constructed at key points along the channel to provide grade control, divert flow away from
the stream banks, and create in -stream habitat. A ford crossing will be installed along the mainstem and a culvert
crossing will be installed along the upper tributary. The banks along both tributaries will be graded create a floodprone
bench.
Mechanical clearing will be limited to those stream banks where grading is essential to establish stable channel geometry.
All disturbed areas impacted within the limits of the project will be seeded with native grasses and planted with native
trees and shrubs. All disturbed areas impacted outside the limits of the project will be seeded with grasses and clover.
Equipment includes: tracked excavators with hydraulic thumbs will be utilized for excavating and grading, and installing
in -stream structures; tracked trucks will be utilized for hauling rock and logs on-site; tracked loaders will be utilized for
hauling materials on-site and fine grading; dump trucks will deliver materials to the site.
Page 3 of 11
PCN Form — Version 1.3 December 10, 2008 Version

4. Jurisdictional Determinations
4a. Have jurisdictional wetland or stream determinations by the
Corps or State been requested or obtained for this property /
El Yes ®No El Unknown
project (including all prior phases) in the past?
Comments:
4b. If the Corps made the jurisdictional determination, what type
El Preliminary El Final
of determination was made?
4c. If yes, who delineated the jurisdictional areas?
Agency/Consultant Company:
Name (if known):
Other:
4d. If yes, list the dates of the Corps jurisdictional determinations or State determinations and attach documentation.
If requested, a pre -application meeting will be held on-site to present the project to the permitting agencies. Mr. Tommy
Burchette, Foothills Consulting will lead the site walk..
5. Project History
5a. Have permits or certifications been requested or obtained for
❑ Yes ® No ❑ Unknown
this project (including all prior phases) in the past?
5b. If yes, explain in detail according to "help file" instructions.
6. Future Project Plans
6a. Is this a phased project?
® Yes ❑ No
6b. If yes, explain.
This is Phase 4 of multi -phase projects proposed for Big Creek. The Phase 1 project completed in 2008 restored 4,036
linear feet, Phase 2 completed in 2013 restored over 4,515 linear feet. Phase 3 completed in 2015 restored 1,596 linear
feet. This Phase 4 project starts where the Phase 3 project ended and is 4,014 linear feet. Additional restoration work
may be conducted on downstream reaches. The additional work is dependent on landowner participation and the
availability of funding.
Page 4 of 11
PCN Form — Version 1.3 December 10, 2008 Version

C. Proposed Impacts Inventory
1. Impacts Summary
1 a. Which sections were completed below for your project (check all that apply):
❑ Wetlands ® Streams - tributaries ❑ Buffers
❑ Open Waters ❑ Pond Construction
2. Wetland Impacts
If there are wetland impacts proposed on the site, then complete this question for each wetland area impacted.
2a.
2b.
2c.
2d.
2e.
2f.
Wetland impact
Type of jurisdiction
number—
Type of impact
Type of wetland
Forested
(Corps - 404, 10
Area of impact
Permanent (P) or
(if known)
DWQ — non -404, other)
(acres)
Temporary (T)
W1 ❑ P ❑ T
❑ Yes
❑ Corps
❑ No
❑ DWQ
W2 ❑ P ❑ T
❑ Yes
❑ Corps
❑ No
❑ DWQ
W3 ❑ P ❑ T
❑ Yes
❑ Corps
❑ No
❑ DWQ
W4 ❑ P ❑ T
❑ Yes
❑ Corps
❑ No
❑ DWQ
W5 ❑ P ❑ T
❑ Yes
❑ Corps
❑ No
❑ DWQ
W6 ❑ P ❑ T
❑ Yes
❑ Corps
❑ No
❑ DWQ
2g. Total wetland impacts
0.0 acres
2h. Comments:
3. Stream Impacts
If there are perennial or intermittent stream impacts (including temporary impacts) proposed on the site, then complete this
question for all stream sites impacted.
3a.
3b.
3c.
3d.
3e.
3f.
3g.
Stream impact
Type of impact
Stream name
Perennial
Type of jurisdiction
Average
Impact
number -
(PER) or
(Corps - 404, 10
stream
length
Permanent (P) or
intermittent
DWQ — non -404,
width
(linear
Temporary (T)
(INT)?
other)
(feet)
feet)
S1 ❑ P ®T
stream bank
Big Creek
® PER
® Corps
30
3,086
grading
❑ INT
® DWQ
S2 ❑ P ®T
stream bank
Unnamed
® PER
® Corps
10
350
grading
Tributary 1
❑ INT
® DWQ
S3 ❑ P ❑ T
stream bank
Unnamed
® PER
® Corps
20
578
grading
Tributary 2
❑ INT
® DWQ
S4 ❑ P ❑ T
❑ PER
❑ Corps
❑ INT
❑ DWQ
S5 ❑ P ❑ T
❑ PER
❑ Corps
❑ INT
❑ DWQ
S6 ❑ P ❑ T
❑ PER
❑ Corps
El INT
El DWQ
3h. Total stream and tributary impacts
4,014
3i. Comments:
Page 5 of 11
PCN Form — Version 1.3 December 10, 2008 Version

4. Open Water Impacts
If there are proposed impacts to lakes, ponds, estuaries, tributaries, sounds, the Atlantic Ocean, or any other open water of
the U.S. then individually list all open water impacts below.
4a.
4b.
4c.
4d.
4e.
Open water
Name of waterbody
impact number -
(if applicable)
Type of impact
Waterbody type
Area of impact (acres)
Permanent (P) or
Temporary (T)
01 ❑P❑T
02 ❑P❑T
03 ❑P❑T
04 ❑P❑T
4f. Total open water impacts
0.0 acres
4g. Comments:
5. Pond or Lake Construction
If pond or lake construction proposed, then complete the chart below.
5a.
5b.
5c.
5d.
5e.
Wetland Impacts (acres)
Stream Impacts (feet)
Upland
Pond ID
Proposed use or purpose
(acres)
number
of pond
Flooded
Filled
Excavated
Flooded
Filled
Excavated
Flooded
P1
P2
5f. Total
5g. Comments:
5h. Is a dam high hazard permit required?
❑ Yes ❑ No If yes, permit ID no:
5i. Expected pond surface area (acres):
5j. Size of pond watershed (acres):
5k. Method of construction:
6. Buffer Impacts (for DWQ)
If project will impact a protected riparian buffer, then complete the chart below. If yes, then individually list all buffer impacts
below. If any impacts require mitigation, then you MUST fill out Section D of this form.
6a.
❑ Neuse ❑ Tar -Pamlico ❑ Other:
Project is in which protected basin?
❑ Catawba ❑ Randleman
6b.
6c.
6d.
6e.
6f.
6g.
Buffer impact
number-
Reason
Buffer
Zone 1 impact
Zone 2 impact
Permanent (P) or
for
Stream name
mitigation
(square feet)
(square feet)
Temporary (T)
impact
required?
B1 ❑P❑T
F-1 Yes
❑ No
B2 ❑P❑T
F-1 Yes
❑ No
B3 ❑P❑T
F-1 Yes
❑ No
6h. Total buffer impacts
6i. Comments:
Page 6 of 11
PCN Form - Version 1.3 December 10, 2008 Version

D. Impact Justification and Mitigation
1. Avoidance and Minimization
1 a. Specifically describe measures taken to avoid or minimize the proposed impacts in designing project.
Since the purpose of the project is to restore the 4,014 LF of the existing stream channels it was not possible to avoid the
impacts.
1 b. Specifically describe measures taken to avoid or minimize the proposed impacts through construction techniques.
1) Grading of streambanks will be conducted from the top of the adjacent floodplain or terrace to the extent practical, 2)
seeding, mulching and installation of coir matting will proceed as channel sections are completed to provide immediate
stabilization.
2. Compensatory Mitigation for Impacts to Waters of the U.S. or Waters of the State
2a. Does the project require Compensatory Mitigation for
impacts to Waters of the U.S. or Waters of the State?
❑ Yes ® No
2b. If yes, mitigation is required by (check all that apply):
❑ DWQ ❑ Corps
2c. If yes, which mitigation option will be used for this
project?
❑ Mitigation bank
ElPayment to in -lieu fee program
❑ Permittee Responsible Mitigation
3. Complete if Using a Mitigation Bank
3a. Name of Mitigation Bank:
3b. Credits Purchased (attach receipt and letter)
Type
Quantity
3c. Comments:
4. Complete if Making a Payment to In -lieu Fee Program
4a. Approval letter from in -lieu fee program is attached.
❑ Yes
4b. Stream mitigation requested:
linear feet
4c. If using stream mitigation, stream temperature:
❑ warm ❑ cool ❑cold
4d. Buffer mitigation requested (DWQ only):
square feet
4e. Riparian wetland mitigation requested:
acres
4f. Non -riparian wetland mitigation requested:
acres
4g. Coastal (tidal) wetland mitigation requested:
acres
4h. Comments:
5. Complete if Using a Permittee Responsible Mitigation Plan
5a. If using a permittee responsible mitigation plan, provide a description of the proposed mitigation plan.
Page 7 of 11
PCN Form — Version 1.3 December 10, 2008 Version

6. Buffer Mitigation (State Regulated Riparian Buffer Rules) — required by DWQ
6a. Will the project result in an impact within a protected riparian buffer that requires
buffer mitigation?
❑ Yes ® No
6b. If yes, then identify the square feet of impact to each zone of the riparian buffer that requires mitigation. Calculate the
amount of mitigation required.
Zone
6c.
Reason for impact
6d.
Total impact
(square feet)
Multiplier
6e.
Required mitigation
(square feet)
Zone 1
3 (2 for Catawba)
Zone 2
1.5
6f. Total buffer mitigation required:
6g. If buffer mitigation is required, discuss what type of mitigation is proposed (e.g., payment to private mitigation bank,
permittee responsible riparian buffer restoration, payment into an approved in -lieu fee fund).
6h. Comments:
Page 8 of 11
PCN Form — Version 1.3 December 10, 2008 Version

E. Stormwater Management and Diffuse Flow Plan (required by DWQ)
1.
Diffuse Flow Plan
1 a.
Does the project include or is it adjacent to protected riparian buffers identified
❑ Yes ® No
within one of the NC Riparian Buffer Protection Rules?
1b.
If yes, then is a diffuse flow plan included? If no, explain why.
❑ Yes ❑ No
Comments:
2.
Stormwater Management Plan
2a.
What is the overall percent imperviousness of this project?
0%
2b.
Does this project require a Stormwater Management Plan?
❑ Yes ® No
2c.
If this project DOES NOT require a Stormwater Management Plan, explain why: Stream restoration on rural agricultural
land
2d.
If this project DOES require a Stormwater Management Plan, then provide a brief, narrative description of the plan:
❑ Certified Local Government
2e.
Who will be responsible for the review of the Stormwater Management Plan?
❑ DWQ Stormwater Program
❑ DWQ 401 Unit
3.
Certified Local Government Stormwater Review
3a.
In which local government's jurisdiction is this project?
❑ Phase II
3b.
Which of the following locally -implemented stormwater management programs
❑ NSW
❑ USMP
apply (check all that apply):
❑ Water Supply Watershed
❑ Other:
3c.
Has the approved Stormwater Management Plan with proof of approval been
❑ Yes ❑ No
attached?
4.
DWQ Stormwater Program Review
❑ Coastal counties
❑ HQW
4a.
Which of the following state -implemented stormwater management programs apply
❑ 0 R
(check all that apply):
❑ Session Law 2006-246
❑ Other:
4b.
Has the approved Stormwater Management Plan with proof of approval been
attached?
❑ Yes ❑ No
5.
DWQ 401 Unit Stormwater Review
5a.
Does the Stormwater Management Plan meet the appropriate requirements?
❑ Yes ❑ No
5b.
Have all of the 401 Unit submittal requirements been met?
❑ Yes ❑ No
Page 9 of 11
PCN Form — Version 1.3 December 10, 2008 Version

F.
Supplementary Information
1.
Environmental Documentation (DWQ Requirement)
1a.
Does the project involve an expenditure of public (federal/state/local) funds or the
® Yes ❑ No
use of public (federal/state) land?
1 b.
If you answered "yes" to the above, does the project require preparation of an
environmental document pursuant to the requirements of the National or State
❑ Yes ® No
(North Carolina) Environmental Policy Act (NEPA/SEPA)?
1 c.
If you answered "yes" to the above, has the document review been finalized by the
State Clearing House? (If so, attach a copy of the NEPA or SEPA final approval
letter.)
❑ Yes ❑ No
Comments:
2.
Violations (DWQ Requirement)
2a.
Is the site in violation of DWQ Wetland Rules (15A NCAC 2H .0500), Isolated
Wetland Rules (15A NCAC 2H .1300), DWQ Surface Water or Wetland Standards,
❑ Yes ® No
or Riparian Buffer Rules (15A NCAC 2B .0200)?
2b.
Is this an after -the -fact permit application?
❑ Yes ® No
2c.
If you answered "yes" to one or both of the above questions, provide an explanation of
the violation(s):
3.
Cumulative Impacts (DWQ Requirement)
3a.
Will this project (based on past and reasonably anticipated future impacts) result in
❑ Yes ® No
additional development, which could impact nearby downstream water quality?
3b.
If you answered "yes" to the above, submit a qualitative or quantitative cumulative impact analysis in accordance with the
most recent DWQ policy. If you answered "no," provide a short narrative description.
4.
Sewage Disposal (DWQ Requirement)
4a.
Clearly detail the ultimate treatment methods and disposition (non -discharge or discharge) of wastewater generated from
the proposed project, or available capacity of the subject facility.
Page 10 of 11
PCN Form — Version 1.3 December 10, 2008 Version

5.
Endangered Species and Designated Critical Habitat (Corps Requirement)
5a.
Will this project occur in or near an area with federally protected species or
❑ Yes ® No
habitat?
5b.
Have you checked with the USFWS concerning Endangered Species Act
❑ Yes ® No
impacts?
F-1 Raleigh
5c.
If yes, indicate the USFWS Field Office you have contacted.
❑ Asheville
5d.
What data sources did you use to determine whether your site would impact Endangered Species or Designated Critical
Habitat?
Previously discussed with Dave McHenry and Mark Fowlkes, North Carolina Wildlife Resource Commission.
6.
Essential Fish Habitat (Corps Requirement)
6a.
Will this project occur in or near an area designated as essential fish habitat?
❑ Yes ® No
6b.
What data sources did you use to determine whether your site would impact Essential Fish Habitat?
During same site meeting with Dave McHenry and Mark Fowlkes, North Carolina Wildlife Resource Commission.
7.
Historic or Prehistoric Cultural Resources (Corps Requirement)
7a.
Will this project occur in or near an area that the state, federal or tribal
governments have designated as having historic or cultural preservation
❑ Yes ® No
status (e.g., National Historic Trust designation or properties significant in
North Carolina history and archaeology)?
7b.
What data sources did you use to determine whether your site would impact historic or archeological resources?
Previous contacts with Dolores Hall, Deputy State Archaeologist to confirm there are no archaeological resources in the
area. and Justin Kockritz, NC Historic Preservation Office to confirm there are no historical resources in the area.
8. Flood Zone Designation (Corps Requirement)
8a.
Will this project occur in a FEMA -designated 100 -year floodplain?
❑ Yes ® No
8b.
If yes, explain how project meets FEMA requirements:
8c. What source(s) did you use to make the floodplain determination? Reviewed NCFloodMaps.com
Rocky Powell
September 12,
2016
Applicant/Agent's Printed Name
Date
Applicant/Agent's Signature
(Agent's signature is valid only if an authorization letter from the applicant
isprovided.)
Page 11 of 11
PCN Form — Version 1.3 December 10, 2008 Version

BIG CREEK IV
STREAM RESTORATION
DESIGN REPORT
September 2016
CLEAR
1317 Knopp Road, Jarrettsville, Maryland 21084
�a
and
-- Consultants & Designers, Inc.
"Integrating Engineering and Environment"
74.55 New Ridge Road, Suite T Phone: [phone]
Hanover, Maryland 21076 Fax: [phone]
X'Vebsite: www.baylandinc.com
CREEKS CONSULTING
[phone]
FOOTHILLS CONSULTING
1026 BEAUMONT POPLAR STREET
NORTH WILKESBORO, NC 28659
[phone]

BIG CREEK IV
STREAM RESTORATION
DESIGN REPORT
PREPARED FOR
RESOURCE INSTITUTE, INC.
and
STOKES COUNTY
SOIL & WATER CONSERVATION DISTRICT
CLEAR CREEKS CONSULTING LLC
IN COLLABORATION WITH
BAYLAND CONSULTANTS & DESIGNERS, INC
and
FOOTHILLS CONSULTING
SEPTEMBER 2016

Big Creek IV Stream Restoration Design Report
TABLE OF CONTENTS
PROJECT BACKGROUND............................................................................................3
TECHNICAL REPORT....................................................................................................4
1. STUDY AREA......................................................................................................4
2. SCOPE OF STUDIES.......................................................................................... 4
3. WATERSHED CHARACTERIZATION................................................................4
3.1. Physiography and Basin Morphometry.................................................4
3.2. Climate......................................................................................................7
3.3. Geology and Soils, and Land Use..........................................................7
3.4. Hydrology.................................................................................................8
3.4.1. Hydrologic Model..........................................................................
8
3.4.2. Regional Regression Equations ...................................................
9
3.4.3. Calibration of Hydrologic Model ..................................................
10
3.4.4. Hydrologic Model Results...........................................................
11
3.5. Hydraulics..............................................................................................13
3.5.1. Hydraulic Model..........................................................................
13
3.5.2. Hydraulic Analysis......................................................................
14
3.5.3. Hydraulic Model Results............................................................. 19
4. CHANNEL MORPHOLOGY AND STABILITY ASSESSMENT .........................19
4.1. Rationale.................................................................................................19
4.2. Assessment Methods............................................................................ 20
4.2.1. Verifying Bankfull Channel Field Indicators ................................ 20
4.2.2. Level II — Morphological Description ........................................... 20
4.2.3. Level III — Assessment of Stream Condition ............................... 20
4.3. Findings of Channel Survey and Field Observations .........................20
5. RESTORATION DESIGN................................................................................... 35
5.1. General Approach..................................................................................35
5.2. Design Criteria....................................................................................... 36
5.2.1. Reference Reach Data............................................................... 36
5.2.2. Design Discharges..................................................................... 36
5.2.3. Channel Geometry..................................................................... 36
5.2.4. Sediment Entrainment Analysis .................................................. 37
REFERENCES.............................................................................................................. 40

Big Creek IV Stream Restoration
LIST OF FIGURES
Design Report
Figure 1 — Big Creek IV Stream Restoration Project Location ......................................... 5
Figure 2 — Big Creek IV Stream Restoration Project Limits ............................................. 6
LIST OF TABLES
Table 1 —
Sub -Basins Drainage Area Characteristics..................................................... 8
Table 2 —
Restoration Reach Study Points......................................................................
9
Table 3 —
TR -20 Calibration for Multiple Storm Frequency Models ...............................
10
Table 4 —
TR -20 Precipitation Input...............................................................................
11
Table 5 —
Calibrated TR -20 Peak Discharges...............................................................
11
Table 6 —
Peak Discharge Comparison: SP01..............................................................
12
Table 7 —
Peak Discharge Comparison: SP02..............................................................
12
Table 8 —
Peak Discharge Comparison: SP03..............................................................
12
Table 9 —
Existing and Proposed River Stationing Descriptions ....................................
13
Table 10
— Peak Discharge Flow Change Locations.....................................................
14
Table 11
— Existing and Proposed Manning's Values ...................................................
14
Table 12
— 1 -YR Hydraulic Analysis..............................................................................
15
Table 13
— 2 -YR Hydraulic Analysis..............................................................................
16
Table 14
— 10 -YR Hydraulic Analysis............................................................................
17
Table 15
— 100 -YR Hydraulic Analysis..........................................................................
18
Table 16
— Existing Conditions Sediment Entrainment Analysis ...................................
38
Table 17
— Proposed Conditions Sediment Entrainment Analysis ................................
39
APPENDICES
Appendix A — Channel Morphology Data
Appendix B — Hydrology and Hydraulic Analysis Supporting Documentation

Big Creek IV Stream Restoration Design Report
PROJECT BACKGROUND
The Resource Institute and the Stokes County Soil and Water Conservation District
(SWCD) have a history of working with interested landowners to improve the water
quality of streams on their property. This project involves restoration of Big Creek along
the June Tilley, Samuel and Joan Rogers, and Dottie Nunn Properties near Mount Airy,
North Carolina close to the Stokes and Surry County line. This is the fourth project on
Big Creek.
In 2008, the Resource Institute and the Surry SWCD worked with landowners to restore
4,036 linear feet of the upper reach of Big Creek. In 2013, they worked with landowners
to restore 4,515 linear feet of Big Creek immediately downstream of the first project. In
2015, the third project restored 1,596 linear feet of Big Creek. The current project, Big
Creek IV, will restore 4,014 linear feet of Big Creek and its tributaries immediately
downstream of the third project. Completion of this phase of the overall restoration effort
will lengthen the restored portion of Big Creek to more than 14,161 linear feet. The
project will improve the water quality of Big Creek by reducing sediment entering the
stream corridor from cultivated fields and stream bank erosion. It will also improve
habitat for aquatic organisms.
Big Creek is a third order tributary of the Dan River in the Roanoke River Basin. The
Dan River is the main source of drinking water for the Town of Eden. The January 2008
Draft Report by the North Carolina Division of Water Quality suggests that the North
Carolina portion of the Dan River has some issues with turbidity and fecal coliform.
The hydrologic and sediment regime of Big Creek and its tributaries have been
historically altered by agricultural activities and development. The channels in the
headwater areas have adjusted in response to direct impacts (i.e. channelization), as
well as indirect impacts (i.e. alterations in watershed hydrology) by incising (i.e. down -
cutting), widening, and eroding laterally. Sediment eroded from these impacted reaches
is still being transported to downstream reaches within the watershed where deposition
initiates lateral adjustments and instability.
It is the intention of the Resource Institute and the Stokes County SWCD to correct the
stream channel instability problems, improve water quality, enhance and/or restore
natural floodplain characteristics, and reduce the loss of agricultural land by
implementing an effective, long-term stream restoration plan for this section of Big
Creek.
3

Big Creek IV Stream Restoration
TECHNICAL REPORT
1, STUDY AREA
Design Report
The study area for the current project includes the stream reaches along Big Creek
starting at a point approximately 4,500 linear feet upstream of Asbury Road and ending
at a point approximately 3,100 linear feet further downstream (Figures 1 and 2).
2. SCOPE OF STUDIES
Existing data was collected and field studies were conducted to: evaluate the current
conditions along Big Creek IV; determine which reaches to restore and the extent of the
restoration effort required; develop reliable estimates of the design discharge(s) and
other design parameters that guided the preparation of restoration design plans; and
satisfy permitting requirements. This study did not include wetland delineations,
identification of significant plant or animal habitat, archeological or historical studies, or
other environmental studies that may be required by local, state or federal permitting
agencies.
3. WATERSHED CHARACTERIZATION
Existing information on watershed characteristics and land use was collected, compiled
and reviewed. The data collected included: topographic, soils, geology, and land use
maps; meteorological data; hydrologic and hydraulic data; and published technical
reports. The following characterization of Big Creek IV watershed was developed from
this information.
3.1. Physiography and Basin Morphometry
The Big Creek watershed is situated in the northeast corner of Surry County and
northwest corner of Stokes County. Its headwaters are bounded by Chestnut Ridge on
the north and west and on the south by NC 89. The watershed lies north of the
Westfield and Woodville communities. This region is situated along the eastern edge of
the Western Piedmont physiographic province and is characterized by gently rolling to
hilly topography.
The Big Creek IV watershed area is 6.51 square miles (4,164.6 acres) at the upstream
end of the project and 10.51 square miles (6,729.0 acres) at the downstream end of the
project. The upper Big Creek watershed is relatively steep and the valley bottoms are
relatively narrow, confined by adjacent hill slopes. Upstream of the project area the
floodplain along the mainstem widens and channel gradient flattens. Except where the
channel flows adjacent to hill slopes, the project reaches are characterized by broad
floodplains, increased sinuosity, and tight meander bends.
11

Big Creek IV Stream Restoration
r•—
Figure 1 — Big Creek IV Stream Restoration Project Location
61
Design Report

Big Creek IV Stream Restoration Design Report
Figure 2 — Big Creek IV Stream Restoration Project Limits

Big Creek IV Stream Restoration Design Report
3.2. Climate
The climate of North Carolina is determined by its location in the warm temperate zone,
but is modified by three important factors: the proximity of the Atlantic Ocean to the
east; the distance of the state from the prevailing course of cyclonic storms; and the
gradual rise in elevation of the land towards the west to the summit of Mt. Mitchell.
Unlike the Coastal Plain, the Western Piedmont extremes of temperature become
greater and rainfall is less. Surry County experiences moderate winters and warm
summers. Mean annual temperature is 58° F. Mean monthly temperatures range from
32 to 50° F in January and 68 to 88 in July.
There are no distinct wet and dry seasons. Most of the rainfall during the growing
season comes from summer thunderstorms, but may vary widely from place to place
and from season to season. Winter rainfall results mostly from low-pressure storms
moving through the area and is less variable than summer rainfall. Mean annual
precipitation is 44.2 inches, with mean monthly precipitation varying from a low of 2.8
inches in November to a high of 4.6 inches in July.
Some snow falls every winter, with total amounts ranging from 1 inch to 2 feet. Mean
annual snowfall is 9 inches. Generally, only a few inches accumulate at one time, and
such accumulations usually melt within a few days.
3.3. Geology and Soils, and Land Use
According to the North Carolina Geological Survey, the Big Creek watershed is located
within the Inner Piedmont Belt, which consists of a variety of metamorphic and igneous
bedrock formations. More specifically, the study area is underlain by Cenozoic biotite
gneiss and schist rock, which is described as inequigranular, locally abundant potassic
feldspar and garnet; interlayered and gradational with calc-silicate, sillimanite-mica
schist, mica schist, and amphibolite (NCGS, 1998). It also contains small masses of
granitic rock.
The dominant upland soils weathered from these rocks are Fairview, Rhodhiss, Toast,
and Woolwine loamy soils. These soils are moderately deep to very deep, well drained
soils. Fairview soils have a sandy clay loam surface layer and clayey subsoil. Moderate
permeability, low to high surface runoff, and moderate to severe erosion hazard
characterize these soils. Rhodhiss soils have a sandy loam surface layer and sandy
clay loam subsoil. Moderate permeability, low to high surface runoff, and moderate to
severe erosion hazard characterize these soils. Toast soils have a coarse sandy loam
surface layer and clay subsoil. Moderate permeability, low to high surface runoff, and
moderate to severe erosion hazard characterize these soils. Woolwine soils have a
gravelly sandy loam surface layer and sandy clay loam, clay, and very gravelly sandy
clay loam subsoils. Moderate permeability, low to high surface runoff, and moderate to
severe erosion hazard characterize these soils.
7

Big Creek IV Stream Restoration Design Report
The dominant floodplain soils along Big Creek are of the Colvard and Suches series.
These very deep, well drained soils formed in sandy loamy alluvial deposits. They have
a fine sandy loam surface layer and subsoil and are characterized by moderately rapid
permeability, slow surface runoff, a moderate to high erosion hazard, and occasional
flooding.
The dominant land use in the watershed is forest (60%) and old field, cultivated land
and pasture (37%) along the ridges, side slopes, and floodplain. Low-density single-
family residential fronting along secondary roads makes up less than 3% of the land
use.
3.4. Hydrology
One of the critical steps necessary for any geomorphic stream design project is
developing accurate estimates of the flow regime, particularly the bankfull discharge.
3.4.1. Hydrologic Model
The Big Creek watershed delineation was expanded from previous work completed for
the first, second, and third phases of the Big Creek Restoration. The hydrologic model
was expanded to include the drainage area to the limit of the fourth phase of restoration,
which included four new sub -drainage areas. The United State Department of
Agriculture (USDA) Soil Conservation Service (SCS) Technical Release -55 (TR -55)
computer program was used to compute the runoff curve number (RCN) and time of
concentration (Tc). The resulting RCN and Tc were incorporated into TR -20: Computer
Program for Project Formulation Hydrology, based upon SCS methodology. Peak
discharges for the existing drainage areas were computed with all computations
assuming good hydrologic conditions. Table 1 lists the delineated sub -basins along with
their corresponding area, runoff curve number, and time of concentration.
Table I
— Sub -Basins Drainage Area
Characteristics
Sub -Basin
Area
(Acres)
Area
(Square
Miles)
Runoff Curve
Number
(RCN
Time of
Concentration
Hours
Big Creek III
4164.6
6.51
58
2.513
Big Creek IV -A
44.5
0.07
62
0.642
Big Creek IV -B
27.9
0.04
64
0.468
Big Creek Tributary #1
73.5
0.11
56
0.411
Big Creek Tributary #2
2427.7
3.79
62
1.538
Along with the watershed sub -basins, study points were selected for the restoration
reaches to provide accurate peak discharge estimates for the proposed restoration
project. Where the overlying watershed hydrology warranted, additional delineations
were provided at the transitions of the selected restoration reaches. Table 2 shows the
E:3

Big Creek IV Stream Restoration
Design Report
computed areas and associated impervious area percentages for each of the proposed
restoration reach study points.
TablePoints
Study Point /
Cumulative
Cumulative
Impervious
Reach ID
Area
Area
Area
Sub -Basins
(Acres)
(Square Miles)
N
SP01
4165
6.51
2.8
Big Creek III
Big Creek III, Big
SP02
4284
6.69
2.7
Creek IV -A,
Tributary #1
SP03
6729
10.51
2.7
All
The SCS TR -20 computer program was used to determine peak discharges at the
selected study points for different storm events by routing the rainfall runoff through the
preexisting channel. The amount of runoff and the speed at which it reached the study
points determined the peak discharge and is a function of the land use, soil type, basin
size and shape, and pre -storm soil moisture. The TR -20 model is a deterministic
hydrologic model that synthesizes a single event runoff hydrograph as a function of a
rainfall input and drainage area characteristics. Rainfall depths and distributions for the
1- to 100 -year, 24-hour storm events were obtained from the National Oceanic and
Atmospheric Administration (NOAA) Atlas 14's Mount Airy, North Carolina station. The
model operates using time varying rainfall to produce a hydrograph that simulates the
role of the watershed area, land cover, hydrologic soil types, antecedent runoff
conditions, topography, storage basins, the characteristics of the overland, shallow
confined, and channel flow paths, and storage attenuation such as that created by flood
plains, wetlands, structures, and ponds. The hydrologic model was calibrated as
described within the Calibration of the Hydrologic Model section of this report. The full
hydrologic model can be found in Appendix B.
3.4.2. Reaional Rearession Eauations
Regression equations were developed to allow interpolation of hydrologic data from
gauged to ungauged sites within North Carolina. This allows estimates of peak
discharge to be made on ungauged streams and rivers. Five distinct physiographic
regions were identified (Blue Ridge, Piedmont, Sand Hills, Southeastern Plains, and
Middle Atlantic Coastal Plain) and regression equations were developed for each
region. The Big Creek Stream Restoration Project is located within the Piedmont region.
Regression analysis is useful in determining whether the hydrologic model has been
sufficiently calibrated to provide the most accurate estimate of peak discharges for the
reach. Regional regression equations from Scientific Investigations Report 2009-5158
"Magnitude and Frequency of Rural Floods in the Southeastern United States, through
2006: Volume 2, North Carolina" by the U.S. Geological Survey, dated 2009 were
employed to analyze the calibrated peak discharges of the hydrologic model. The
hydrologic model was considered successfully calibrated if the peak discharges were
within one standard error of the regional regression peak discharge estimates. Appendix
M

Big Creek IV Stream Restoration
Design Report
B list the NC USGS regional regression equations used to determine the success of the
hydrologic model calibration.
3.4.3. Calibration of Hvdroloaic Model
The TR -20 hydrologic model developed for this project was calibrated by adjusting the
drainage area characteristics and inputs such as the antecedent runoff condition (ARC)
and the rainfall distribution. Calibration is necessary because the TR -20 modeling
software has been shown to over predict peak flows for all return periods. Regional
regression equations were used to provide a baseline for the calibration because they
were developed using flow data from stream gauges which provide an indication of the
current drainage characteristics of the watershed. Table 3 lists the TR -20 input
elements and the application for calibration based on multiple storm frequency models.
---r Table 3 — TR -20 Calibration
for Multiple Storm Frequency Models An—
Application
Input Element /
Calibration Variable
Drainage Area
Same for all storms
Time of Concentration variables
Same for all storms
RCN conditions
Same for all storms
Reach Length
May increase for greater return periods but not reverse
Dimensionless Unit Hydrograph
Same for all storms
Rainfall Table — 24 -hr duration
Use for 25 -yr to 500 -yr storms
Rainfall Table — 12 -hr duration
May use for the 2 through 10 -yr storms.
Rainfall Table — 6 -hr duration
May use for 2, 5 and 10 -yr storms.
Use 2 for 25 -yr and greater return period storms. May
ARC (Antecedent Runoff
use <2 for the 2 -yr to 10 -yr storms provided that it does
Condition)
not decrease for greater return period storms. ARC of >2
may be considered for storms of 200+ -yrs providing that
it does not decrease with greater return period storms
The antecedent runoff condition (ARC) is a measure of the soil moisture directly before
a storm event. Typical values range from 1-3 with 1 representing dry soil conditions and
3 representing wet soil conditions. An ARC value of 2 represents the preliminary wetting
of the ground surface and the filling of small depressions and is appropriate for severe
storm events (10- to 100 -year) because they are typically related to longer cyclonic
events. An ARC value of 1 is more appropriate for short duration, summer thunder
storms which generally occur with the more frequent 1- to 10 -year storm events. The
TR -20 program only accepts integer ARC values; therefore, one calibration method is to
recalculate the RCN based on a fractional ARC value. This is most appropriate for
shorter return period storms (1- to 10 -year). The equations for recalculating the RCN
are as follows.
10

Big Creek IV Stream Restoration
For ARC <- 2: RCN(x)-
For
CN(X)_
For ARC >- 2: RCN(x) _
[10+5.8(X-2)]RCN2
10+0.13(x-2)RCN2
[10+13(X-2)]RCN2
10+0.13(x-2)RCN2
Design Report
Where x = ARC value and is a real number between 1 and 3 and RCN2 is the pre -
calibrated RCN of the drainage area.
The model was calibrated by selecting a fractional ARC value and calculating the
corresponding RCN. This RCN value was input into the TR -20 model and a peak
discharge was calculated. If the TR -20 peak discharge did not fall within one standard
error of the peak discharge determined using the regional regression equations, then a
new fractional ARC was chosen and the corresponding RCN value was input into TR -
20. This process continued until the TR -20 peak discharge fell within one standard error
of the peak discharge from the regional regression equation. Table 4 lists the calibrated
inputs used for the various storm events for each drainage area and Table 5 lists the
computed calibrated peak discharges for each study point.
Study
Point
Storm Event
Rainfall Distribution
Rainfall
(Inches)
Selected
ARC
1 -YR
24 -hr NOAA C
3.00
2.0
2 -YR
24 -hr NOAA C
3.64
2.0
5 -YR
24 -hr NOAA C
4.64
2.0
10 -YR
24 -hr NOAA C
5.47
2.0
25 -YR
24 -hr NOAA C
6.66
2.0
50 -YR
24 -hr NOAA C
7.67
2.0
100 -YR
24 -hr NOAA C
8.76
2.0
Study
Point
1 -YR
(cfs)
F1 P"I MiMM
2 -YR
(cfs)
H OTFIM
5 -YR
(cfs)
.-
10 -YR 25 -YR
(cfs) (cfs)
50 -YR
(cfs)
100 -YR
(cfs)
SP01
191.1
418.6
908.2
1394.9
2171.4
2876.9
3630.7
SP02
194.6
424.0
919.1
1409.9
2197.1
2906.8
3662.8
SP03
375.6
790.6
1664.1
2512.0
3843.3
5024.1
6270.0
3.4.4. Hydrologic Model Results
Tables 6 through 8 compare the regional regression equations with the calibrated TR -20
Peak Discharges to determine whether the calibration was successful in achieving the
target values within one standard error of the regional regression equations.
11

Big Creek IV Stream Restoration
Design Report
The TR -20 peak discharges were successfully calibrated for the more frequent 2 -
through 10 -year storm events for all study points, while the 50- and 100 -year storm
events were slightly above the upper regression limits for SP01 and SP02. The TR -20
discharges for the 50- and 100 -year events for SP03 were well above the upper limit of
the regression equation. One explanation is that the drainage area was subdivided into
four areas, and the hydrograph peaks for the two largest drainage basins coincided,
producing a larger peak discharge than predicted by the regression equations which do
not take into account routing of multiple drainage basins. Notwithstanding the 50- and
12
I Table 6
- Peak Discharge
Comparison:
SP01
TR -20
Storm
Regression
Standard
Lower
Upper
TR -20
Recurrence
Peak
Error
Limit
Limit
Peak
Interval
Discharge
M
(cfs)
(cfs)
Discharge
(yrs)
(cfs)
2
543
34.5%
(cfs)
2
533
34.5%
349
717
418.6
5
955
41.2%
561
1348
908.2
10
1264
35.1%
820
1708
1394.9
50
2033
39.6%
1228
2839
2876.9
100
2361
41.9%
1371
3350
3630.7
The TR -20 peak discharges were successfully calibrated for the more frequent 2 -
through 10 -year storm events for all study points, while the 50- and 100 -year storm
events were slightly above the upper regression limits for SP01 and SP02. The TR -20
discharges for the 50- and 100 -year events for SP03 were well above the upper limit of
the regression equation. One explanation is that the drainage area was subdivided into
four areas, and the hydrograph peaks for the two largest drainage basins coincided,
producing a larger peak discharge than predicted by the regression equations which do
not take into account routing of multiple drainage basins. Notwithstanding the 50- and
12
..
Standard
.- 0 tHWAlziel-1
Lower
Upper
TR -20
Storm
Regression
Recurrence
Peak
Error
Limit
Limit
Peak
Interval
Discharge
N
(cfs)
(cfs)
Discharge
(yrs)
(cfs)
(cfs)
Discharge
(yrs)
(cfs)
2
543
34.5%
355
730
424.0
5
972
41.2%
571
1372
919.1
10
1286
35.1%
835
1738
1409.9
50
2068
39.6%
1249
2887
2906.8
100
2401
41.9%
1395
3406
3662.8
The TR -20 peak discharges were successfully calibrated for the more frequent 2 -
through 10 -year storm events for all study points, while the 50- and 100 -year storm
events were slightly above the upper regression limits for SP01 and SP02. The TR -20
discharges for the 50- and 100 -year events for SP03 were well above the upper limit of
the regression equation. One explanation is that the drainage area was subdivided into
four areas, and the hydrograph peaks for the two largest drainage basins coincided,
producing a larger peak discharge than predicted by the regression equations which do
not take into account routing of multiple drainage basins. Notwithstanding the 50- and
12
Storm
Regression
Standard
Lower
Upper
TR -20
Recurrence
Peak
Error
Limit
Limit
Peak
Interval
Discharge
N
(cfs)
(cfs)
Discharge
(yrs)
(cfs)
(cfs)
2
727
34.5%
476
978
790.6
5
1290
41.2%
758
1821
1664.1
10
1699
35.1%
1103
2296
2512.0
50
2712
39.6%
1638
3786
5024.1
100
3139
41.9%
1824
4454
6270.0
The TR -20 peak discharges were successfully calibrated for the more frequent 2 -
through 10 -year storm events for all study points, while the 50- and 100 -year storm
events were slightly above the upper regression limits for SP01 and SP02. The TR -20
discharges for the 50- and 100 -year events for SP03 were well above the upper limit of
the regression equation. One explanation is that the drainage area was subdivided into
four areas, and the hydrograph peaks for the two largest drainage basins coincided,
producing a larger peak discharge than predicted by the regression equations which do
not take into account routing of multiple drainage basins. Notwithstanding the 50- and
12

Big Creek IV Stream Restoration Design Report
100 -year storms being outside the calibration window for all three study points, no
further calibration was performed. This is because the more frequent storm events (2- to
10 -year) which are typically used in stream design were successfully calibrated, and
that the larger, less frequent storm events are most likely outside the calibration limits
due to the subdivision of the watershed and the inability of the regression equations to
take into account channel routing.
3.5. Hydraulics
3.5.1. Hydraulic Model
HEC -RAS version 5.0.1 River Analysis System, developed by the U.S. Army Corps of
Engineers, was used to establish the water surface, velocity, and channel shear
stresses for the Big Creek Stream Restoration Project existing and proposed conditions.
Table 9 describes the hydraulic cross sections for Big Creek IV and its two tributaries.
Table •Proposed
Big Creek IV & Tributaries #1 #2
and
River Stations Description
Big Creek
20.5-20.7
Existing: Upstream Limits of Study
Proposed: No Changes
7-20
Existing: Mid Reach Cross Sections
Proposed: Natural Channel Design Sections — XS1 through XS20
0.1-0.5
Existing: Downstream Limits of Study
Proposed: No Changes
Tributary #1
1-2
Existing: Tributary #1 Cross Sections
Proposed: Natural Channel Design Section — TRIB #1 XS1 through XS2
Tributary #2
1-5
Existing: Tributary #2 Cross Sections
Proposed: Natural Channel Design Section — TRIB #2 XS 1 through XS5
Table 10 identifies the developed study point peak discharges with the associated cross
section hydraulic models flow change locations.
13

Big Creek IV Stream Restoration
Design Report
low Change
Table .- FLocations
All Reaches
River 1 -YR 2 -YR 10 -YR 100 -YR
Station (cfs)(cfs)_(cfs) (cfs)
Big Creek
20.7
191.1
418.6
1394.9
3630.7
6
194.6
424.0
1409.9
3662.8
0.5
375.6
790.6
2512.0
6270.0
Tributary #1
2.1
5.0
15.9
64.8
161.0
Tributary #2
5.1
246.5
491.8
1421.1
3285.1
Table 11 identifies the field measured existing stream channel Manning's values and
the proposed stream restoration design values.
3.5.2. Hydraulic Analysis
Tables 12 through 15 detail the results of the hydraulic comparison between existing
and proposed conditions for the 1-, 2-, 10- and 100 -year storm events for Big Creek IV
and its two tributaries. The results highlight the changes in the water surface elevation,
channel velocity and channel shear stresses. The full hydraulic model can be found in
Appendix B.
14

Big Creek IV Stream Restoration
Design Report
15
Table 12 - 1 -YR Hydraulic Analysis
Big Creek IV & Tributaries #1
and #2 AMM""ML
EX. PR. Change
Change Channel Channel Channel
Velocity Shear Shear Shear
Stress Stress Stress
River
Station
EX.
W.S.
Elevation
PR. Change
W.S. W.S
Elevation Elevation
EX. PR.
Velocity Velocity
(ft)
(ft) (ft)
(ft/s) (ft/s)
(%)
(Ib/sq ft)
(Ib/sq ft)
(%)
Big Creek
20.5
1069.91
1069.56
-0.35
3.17
3.74
17.98
0.35
0.51
45.71
20
1069.26
1068.66
-0.60
3.79
4.70
24.01
0.58
0.85
46.55
19
1068.85
1068.58
-0.27
3.56
2.19
-38.48
0.48
0.16
-66.67
18
1068.81
1068.52
-0.29
1.90
1.91
0.53
0.11
0.11
0.00
17
1068.75
1068.08
-0.67
2.08
4.63
122.60
0.14
0.83
492.86
16
1068.69
1067.90
-0.79
1.42
2.05
44.37
0.07
0.14
100.00
15
1068.38
1067.27
-1.11
2.57
4.81
87.16
0.24
0.90
275.00
14
1068.21
1066.90
-1.31
2.40
2.38
-0.83
0.20
0.18
-10.00
13
1066.92
1065.85
-1.07
3.21
4.32
34.58
0.36
0.71
97.22
12
1066.64
1065.68
-0.96
2.60
2.28
-12.31
0.24
0.17
-29.17
11
1066.19
1065.45
-0.74
2.97
2.09
-29.63
0.31
0.14
-54.84
10
1065.92
1064.91
-1.01
3.00
3.96
32.00
0.30
0.58
93.33
9
1065.16
1064.49
-0.67
3.89
2.15
-44.73
0.55
0.15
-72.73
8
1064.81
1063.98
-0.83
2.32
3.93
69.40
0.19
0.57
200.00
7
1064.44
1063.58
-0.86
2.19
3.73
70.32
0.17
0.51
200.00
6
1064.05
1063.07
-0.98
3.79
3.85
1.58
0.51
0.54
5.88
5
1063.67
1061.82
-1.85
1.80
3.43
90.56
0.11
0.41
272.73
4
1063.41
1061.75
-1.66
3.18
2.37
-25.47
0.36
0.18
-50.00
3
1063.16
1061.45
-1.71
2.97
4.00
34.68
0.33
0.59
78.79
2
1062.29
1061.16
-1.13
2.05
2.32
13.17
0.14
0.18
28.57
1
1061.83
1060.96
-0.87
2.92
2.13
-27.05
0.29
0.14
-51.72
0.5
1060.16
1060.19
0.03
5.77
5.70
-1.21
1.18
1.14
-3.39
Tributary #1
2
1065.11
1065.04
-0.07
1.19
2.34
96.64
0.07
0.32
357.14
1
1065.06
1064.20
-0.86
0.60
2.47
311.67
0.02
0.37
1750.00
Tributary #2
5
1063.48
1062.32
-1.16
1.00
6.82
582.00
0.04
1.77
4325.00
4
1063.42
1061.71
-1.71
1.43
3.71
159.44
0.07
0.44
528.57
3
1062.53
1061.35
-1.18
6.31
3.59
-43.11
1.48
0.44
-70.27
2
1062.19
1061.09
-1.10
2.79
2.90
3.94
0.30
0.28
-6.67
1
1061.45
1061.00
-0.45
5.64
2.63
-53.37
1.11
0.20
-81.98
15

Big Creek IV Stream Restoration
Design Report
16
Table 13 - 2 -YR Hydraulic Analysis
Big Creek IV & Tributaries #1
EX. PR. Change
W.S. W.S. W.S EX. PR.
Elevation Elevation Elevation Velocity Velocity
and #2 AMM""ML
EX. PR. Change
Change Channel Channel Channel
Velocity Shear Shear Shear
Stress Stress Stress
River
Station
(ft)
(ft) (ft)
(ft/s) (ft/s)
(%)
(Ib/sq ft)
(Ib/sq ft)
(%)
Big Creek
20.5
1071.18
1070.93
-0.25
4.26
4.29
0.70
0.54
0.82
51.85
20
1070.64
1070.09
-0.55
4.03
5.32
32.01
0.55
0.93
69.09
19
1070.40
1070.08
-0.32
3.81
3.19
-16.27
0.48
0.31
-35.42
18
1070.34
1069.98
-0.36
2.85
2.98
4.56
0.23
0.25
8.70
17
1070.27
1069.50
-0.77
2.73
5.27
93.04
0.23
0.92
300.00
16
1070.24
1069.41
-0.83
1.78
3.03
70.22
0.10
0.27
170.00
15
1069.96
1068.86
-1.10
3.16
5.09
61.08
0.33
0.84
154.55
14
1069.80
1068.48
-1.32
3.04
3.42
12.50
0.29
0.33
13.79
13
1068.39
1067.48
-0.91
4.28
4.73
10.51
0.59
0.71
20.34
12
1068.18
1067.40
-0.78
3.07
3.16
2.93
0.31
0.30
-3.23
11
1067.73
1067.09
-0.64
3.45
3.03
-12.17
0.40
0.27
-32.50
10
1067.43
1066.55
-0.88
3.98
4.42
11.06
0.52
0.61
17.31
9
1066.36
1065.99
-0.37
5.20
3.23
-37.88
0.89
0.31
-65.17
8
1066.20
1065.27
-0.93
3.17
4.99
57.41
0.31
0.81
161.29
7
1065.88
1064.88
-1.00
2.84
4.80
69.01
0.25
0.74
196.00
6
1065.39
1064.39
-1.00
4.78
4.88
2.09
0.76
0.76
0.00
5
1064.97
1063.53
-1.44
2.47
4.12
66.80
0.18
0.53
194.44
4
1064.61
1063.44
-1.17
4.24
3.29
-22.41
0.62
0.32
-48.39
3
1064.52
1063.20
-1.32
3.02
4.29
42.05
0.31
0.57
83.87
2
1064.02
1062.92
-1.10
2.61
3.17
21.46
0.20
0.30
50.00
1
1063.64
1062.66
-0.98
3.52
3.06
-13.07
0.40
0.27
-32.50
0.5
1061.47
1061.50
0.03
7.53
7.44
-1.20
1.77
1.72
-2.82
Tributary #1
2
1066.57
1065.78
-0.79
0.93
2.29
146.24
0.04
0.26
550.00
1
1066.55
1065.62
-0.93
0.70
1.24
77.14
0.02
0.07
250.00
Tributary #2
5
1065.07
1063.53
-1.54
1.05
7.79
641.90
0.04
1.95
4775.00
4
1064.99
1063.28
-1.71
1.86
4.72
153.76
0.11
0.63
472.73
3
1064.06
1063.00
-1.06
6.73
4.32
-35.81
1.46
0.57
-60.96
2
1063.84
1062.79
-1.05
3.57
3.67
2.80
0.47
0.39
-17.02
1
1062.95
1062.69
-0.26
6.61
3.58
-45.84
1.39
0.34
-75.54
16

Big Creek IV Stream Restoration
Design Report
17
Table 14 - 10 -YR Hydraulic
Big Creek IV & Tributaries
Analysis
#1
PR.
Velocity
and #2
EX. PR. Change
Change Channel Channel Channel
Velocity Shear Shear Shear
Stress Stress Stress
River
Station
EX.
W.S.
Elevation
PR. Change
W.S. W.S
Elevation Elevation
EX.
Velocity
(ft)
(ft) (ft)
(ft/s)
(ft/s)
(%)
(Ib/sq ft)
(Ib/sq ft)
(%)
Big Creek
20.5
1073.38
1073.28
-0.10
4.62
3.86
-16.45
0.54
0.64
18.52
20
1073.21
1072.92
-0.29
3.50
5.09
45.43
0.31
0.68
119.35
19
1072.83
1072.91
0.08
3.73
3.84
2.95
0.39
0.38
-2.56
18
1072.66
1072.24
-0.42
4.18
6.64
58.85
0.45
1.10
144.44
17
1072.41
1072.49
0.08
3.56
4.18
17.42
0.35
0.45
28.57
16
1072.36
1072.40
0.04
2.78
3.65
31.29
0.20
0.34
70.00
15
1071.74
1071.58
-0.16
5.73
7.56
31.94
1.02
1.49
46.08
14
1071.54
1071.19
-0.35
4.74
5.66
19.41
0.62
0.79
27.42
13
1070.58
1070.32
-0.26
5.05
5.82
15.25
0.71
0.87
22.54
12
1070.38
1070.28
-0.10
4.05
4.43
9.38
0.51
0.50
-1.96
11
1069.87
1069.81
-0.06
4.96
4.97
0.20
0.69
0.63
-8.70
10
1069.59
1069.49
-0.10
5.28
5.07
-3.98
0.83
0.65
-21.69
9
1069.41
1069.02
-0.39
4.12
4.49
8.98
0.49
0.50
2.04
8
1068.53
1068.62
0.09
4.69
5.11
8.96
0.59
0.65
10.17
7
1068.27
1068.21
-0.06
3.98
5.32
33.67
0.49
0.71
44.90
6
1067.91
1067.09
-0.82
5.30
8.28
56.23
0.83
1.77
113.25
5
1067.61
1067.25
-0.36
2.94
3.13
6.46
0.24
0.27
12.50
4
1067.47
1067.15
-0.32
3.48
3.70
6.32
0.41
0.33
-19.51
3
1067.45
1067.15
-0.30
2.98
3.30
10.74
0.26
0.26
0.00
2
1067.10
1066.79
-0.31
3.84
4.38
14.06
0.37
0.47
27.03
1
1067.02
1066.64
-0.38
3.02
3.68
21.85
0.24
0.31
29.17
0.5
1065.86
1065.45
-0.41
7.47
8.70
16.47
1.40
1.92
37.14
Tributary #1
2
1068.68
1068.80
0.12
1.12
1.10
-1.79
0.05
0.04
-20.00
1
1068.68
1068.80
0.12
0.75
0.61
-18.67
0.02
0.01
-50.00
Tributary #2
5
1067.12
1067.08
-0.04
1.64
4.54
176.83
0.09
0.51
466.67
4
1066.91
1066.66
-0.25
3.33
5.57
67.27
0.35
0.73
108.57
3
1066.91
1066.78
-0.13
2.50
2.67
6.80
0.19
0.17
-10.53
2
1066.86
1066.75
-0.11
1.96
2.35
19.90
0.13
0.13
0.00
1
1066.79
1066.70
-0.09
2.64
2.90
9.85
0.18
0.19
5.56
17

Big Creek IV Stream Restoration
Design Report
18
F167MMIMMINJ :a:
11MVE91
EX. PR. Change
W.S. W.S. W.S. EX.
Elevation Elevation Elevation Velocity
LTG MM i WA
PR.
Velocity
-M-M -AN-
EX. PR. Change
Change Channel Channel Channel
Velocity Shear Shear Shear
Stress Stress Stress
River
Station
(ft)
(ft) (ft)
(ft/s)
(ft/s)
(%)
(Ib/sq ft)
(Ib/sq ft)
(%)
Big Creek
20.5
1074.54
1074.64
0.10
7.02
5.26
-25.07
1.18
1.08
-8.47
20
1074.24
1074.23
-0.01
5.42
6.79
25.28
0.75
1.12
49.33
19
1074.12
1074.17
0.05
5.22
5.63
7.85
0.70
0.77
10.00
18
1073.89
1073.96
0.07
5.98
6.18
3.34
0.88
0.89
1.14
17
1073.82
1073.92
0.10
4.67
5.17
10.71
0.55
0.64
16.36
16
1073.70
1073.77
0.07
4.28
5.08
18.69
0.45
0.61
35.56
15
1073.29
1073.52
0.23
6.19
6.59
6.46
1.08
1.02
-5.56
14
1073.03
1073.02
-0.01
5.87
6.56
11.75
0.87
0.99
13.79
13
1072.26
1072.35
0.09
5.69
5.94
4.39
0.82
0.82
0.00
12
1071.96
1072.21
0.25
5.45
5.52
1.28
0.84
0.71
-15.48
11
1071.18
1071.58
0.40
7.49
6.78
-9.48
1.43
1.09
-23.78
10
1070.79
1071.19
0.40
7.64
6.58
-13.87
1.61
1.00
-37.89
9
1070.23
1070.48
0.25
7.25
6.45
-11.03
1.45
0.98
-32.41
8
1070.10
1069.85
-0.25
5.72
7.12
24.48
0.81
1.20
48.15
7
1069.99
1069.79
-0.20
4.39
5.89
34.17
0.54
0.80
48.15
6
1069.88
1069.67
-0.21
4.23
5.23
23.64
0.47
0.62
31.91
5
1069.66
1069.51
-0.15
3.44
3.42
-0.58
0.30
0.28
-6.67
4
1069.55
1069.40
-0.15
3.71
4.49
21.02
0.43
0.44
2.33
3
1069.54
1069.41
-0.13
3.47
4.03
16.14
0.32
0.35
9.37
2
1069.28
1069.08
-0.20
4.48
4.82
7.59
0.45
0.52
15.56
1
1069.23
1068.90
-0.33
3.29
4.16
26.44
0.26
0.37
42.31
0.5
1067.76
1067.22
-0.54
10.18
11.93
17.19
2.39
3.33
39.33
Tributary #1
2
1070.20
1070.05
-0.15
1.09
1.30
19.27
0.04
0.05
25.00
1
1070.20
1070.05
-0.15
0.67
0.68
1.49
0.01
0.01
0.00
Tributary #2
5
1069.11
1069.05
-0.06
2.03
4.23
108.37
0.13
0.40
207.69
4
1069.04
1068.97
-0.07
2.70
3.93
45.56
0.21
0.33
57.14
3
1069.02
1068.96
-0.06
2.32
2.49
7.33
0.14
0.14
0.00
2
1069.00
1068.94
-0.06
1.67
2.01
20.36
0.08
0.09
12.50
1
1068.98
1068.92
-0.06
2.11
2.55
20.85
0.11
0.14
27.27
18

Big Creek IV Stream Restoration Design Report
3.5.3. Hvdraulic Model Results
The hydraulic analysis indicates that the proposed stream restoration project will reduce
the water surface elevation, channel velocities and channel shear stress at several
cross sections, while several cross sections show increases in water surface elevation,
channel velocities and channel shear stresses. These increases are attributed to the
geomorphological changes of the spacing stream features (pools and riffles, etc.) along
with stream meander geometry changes from the existing to the proposed conditions
and do not reflect any adverse changes to the proposed reach. The proposed channel
velocities and shear stresses are non-erosive for the proposed stream restoration bed
material and channel stability. The stream restoration project will focus on the addition
of riverine structures and grade controls to prevent future degradation and provide
habitat for aquatic species. Implementation of a vigorous, native landscaping and
limitation of access by adjacent agricultural use will greatly improve the aesthetics and
prevent any future degradation of this reach. Flooding risks to landowners are not
increased by the stream restoration project. The locations of the hydraulic cross
sections and a map of the existing and proposed 100 -year water surface elevations is
provided in Appendix B.
4. CHANNEL MORPHOLOGY AND STABILITY ASSESSMENT
4.1.. Rationale
Stream stability is morphologically defined as the ability of the stream to maintain, over
time, its dimension, pattern and profile in such a manner that it is neither aggrading or
degrading and is able to effectively transport the flows and sediment delivered to it by its
watershed. Morphologic stability permits the full expression of natural stream
characteristics.
Stream potential is defined as the best condition, based on quantifiable morphological
characteristics, for a given stream type. Streams functioning at full potential exhibit a
desired or preferred set of stability or condition characteristics that may be quantitatively
described in terms of channel size and shape, bed stability/vertical control, and bank
stability/lateral control — low bank erosion potential and gradual lateral migration rates.
Stream classification as a morphologic stream assessment technique permits a
quantitative analysis of the degree to which existing conditions differ from an accepted
range of morphological values documented for different stable stream types. The
degree of departure for an existing stream condition from its full stable operating
potential can be determined in a number of ways including comparisons to: 1)
geomorphologic databases; 2) historical photography or surveys of the same reach; and
3) stable reference reaches of the same stream type at different points in the watershed
or adjacent watersheds.
19

Big Creek IV Stream Restoration Design Report
4.2. Assessment Methods
4.2.1. Verifying Bankfull Channel Field Indicators
Updated regional regressions for bankfull channel dimensions developed for use in the
rural Piedmont Region of North Carolina (NCSU and NRCS, 2006) were utilized to
verify field indicators associated with the bankfull channel in conducting the geomorphic
stream assessments along Big Creek.
4.2.2. Level II — Morphological Description
The reaches along Big Creek in the project area were classified into specific categories
of stream types (i.e. B4c, C4, F4, etc.) utilizing the standard field procedures
recommended by Rosgen (1996).
4.2.3. Level III —Assessment of Stream Condition
A stability assessment was not conducted. Observations on the current channel
conditions were recorded and photo -documented.
Findings of Channel Survey and Field Observations
The following is a summary of the findings of the field evaluation as it relates to the
existing conditions within the project study area:
Mainstem
The mainstem reach of the project area is an unstable E4/C4 stream type. A
comparison of channel geometry with that of the reference reach database indicates
that this reach has a width to depth ratio at the low end of the range. Overall gradient is
very flat. Riffles are relatively short with moderate slopes. Pools are moderately long
and moderately deep with very flat slopes.
Channel plan form is characterized by moderate sinuosity and tight meander geometry
with low radii of curvature along the bends. A very tight bend along the lower section of
the reach is undergoing a chute cutoff.
The overall condition of the mainstem reach is characterized by lateral erosion, high
sediment supply, severely undercut trees, and vertical instability (aggradation) and large
debris jams. Fine sediment deposition, lateral and mid -channel bars are evident
throughout. Although the banks support scattered trees and shrubs, bank erosion was
evident throughout.
20

Big Creek IV Stream Restoration Design Report
Tributary #1
This project reach is an unstable E4. Overall gradient is very flat. Riffles are relatively
short with steep slopes. Pools are short and shallow with flat slopes. Channel plan form
is characterized by moderate sinuosity and tight meander geometry with low radii of
curvature along the bends. The overall condition of the tributary is characterized by
localized bank erosion and a moderate sediment supply.
Tributary #2
This project reach is an unstable B5/4c. Overall gradient is very flat. Riffles are relatively
short with steep slopes. Pools are short and shallow with flat slopes. Channel plan form
is characterized by moderate sinuosity and tight meander geometry with low radii of
curvature along the bends. A very tight bend along the middle section of the reach is
undergoing a chute cutoff.
The overall condition of the tributary is characterized by lateral erosion, very high
sediment supply, undercut and fallen trees, and vertical instability (aggradation). Fine
sediment deposition, large point, lateral and mid -channel bars are evident throughout.
Although the banks support scattered trees and shrubs, localized bank erosion was
evident throughout.
21

Big Creek IV Stream Restoration
Design Report
Photo 1 — Looking upstream to start of project reach
Photo 2 — Looking downstream along start of project reach
22

Big Creek IV Stream Restoration
Design Report
Photo 3 — Large mid -channel bar along upper section of project reach
Photo 4 — Looking downstream along relatively stable section
23

Big Creek IV Stream Restoration
Design Report
i
Photo 5 — Looking at left bank along stable section
Photo 6 — Undercut and leaning tree and debris jam along middle section
24

Big Creek IV Stream Restoration
Design Report
Photo 7 — Tight meander bend along middle section
Photo 8 — Eroding bank along outside of tight meander bend in middle section
25

Big Creek IV Stream Restoration
Design Report
Photo 9 — Eroding bank along middle section
Photo 10 — Lateral bar along middle section
26

fl+� lo"
{ , F
ti

Big Creek IV Stream Restoration
Design Report
Photo 13 — Large debris jam along middle section
Photo 14 — Looking downstream along Tributary #1
28

Big Creek IV Stream Restoration
Design Report
Photo 15 — Large lateral bar along lower section
Photo 16 — Over wide channel with lateral bar along lower section
29

Big Creek IV Stream Restoration
Design Report
N 4w
Photo 17 — Eroding bank along lower section
�•��' x 1 r f �� jr/p �
tk 4�� � ` �^H�.�.k�Y r,� '"`' yy� �k a �,fr,'4 �.i1 '31�n+ k i t;• 4.
, y -. ratio.• '�
_
Photo 18 — Upstream end of chute cutoff channel forming across floodplain in lower
section
30

Big Creek IV Stream Restoration
Design Report
vM
Photo 19 — Fallen tree and mid -channel bar along lower section
Photo 20 — Downstream end of chute cutoff channel forming across floodplain in lower
section
31

Big Creek IV Stream Restoration Design Report
M13�'n +a �'�.���?!.',..tyrl�r��� �, � t;. {�1 1�.�'�}3 3 i{ v�. �-i- Sa�,�Cw�•r,v'". _
,'`..,�,`�- d'�'. �' \.� �: moi•-�_ _ -_-
Photo 21 — Confluence of Tributary #2 and mainstem
!"•+Wyk � ,: �d�da�• _
. .. y,• 'mss.;':
Photo 22 — Looking upstream along Tributary #2 from confluence
32
[a
�
y
s:a't t 'r..�} �.r.1rJ,i,IIYP�*fy�
!"•+Wyk � ,: �d�da�• _
. .. y,• 'mss.;':
Photo 22 — Looking upstream along Tributary #2 from confluence
32

Big Creek IV Stream Restoration
Design Report
Photo 23 — Looking upstream at undercut and leaning tree along Tributary #2
Photo 24 — Looking upstream at eroding bank and mid -channel bar along Tributary #2
33

Big Creek IV Stream Restoration
Design Report
r -FO;
r � , t
Photo 25 — Looking upstream at fallen tree and eroding bank along Tributary #2
Photo 26 — Looking upstream at chute cutoff channel forming along Tributary #2
34
F
r r
4t'
z
Ai-
r -FO;
r � , t
Photo 25 — Looking upstream at fallen tree and eroding bank along Tributary #2
Photo 26 — Looking upstream at chute cutoff channel forming along Tributary #2
34

Big Creek IV Stream Restoration
5. RESTORATION DESIGN
5.1. General Approach
Design Report
As pointed out in the Findings of Channel Survey and Field Observations Section, Big
Creek has been affected by alterations in watershed hydrology and sediment supply
associated with agricultural practices, roads and development in the upper watershed.
In addition, direct impacts to the channel and adjacent riparian area have occurred as a
result of straightening and channelization, clearing of riparian vegetation, and runoff
from cultivated fields.
The restoration objectives for Big Creek and its tributaries include:
1. Overall channel geometry and slope will be modified to improve sediment
transport capacity. This will be accomplished by reconstructing unstable C4
reaches along the mainstem as stable C4 channels. Unstable E4 and B5c
reaches along the tributaries will be reconstructed as stable E4 and 135c reaches.
2. Reaches with high width/depth ratios will be reconstructed with a narrower
baseflow and bankfull channel to improve habitat as well as sediment transport.
This will be accomplished by constructing bankfull benches along the channel
margin.
3. High, vertical banks on the outside of the meander bends as well as the adjacent
floodplain will be excavated and graded to establish a better angle of repose on
the banks, increase floodprone area, and lower the bankfull to bank height ratio.
Particular emphasis will be placed on grading those banks lacking woody
vegetation and preserving those banks that are well vegetated with trees and
shrubs.
4. Meander geometry will be modified to increase radii of curvature on bends where
the radii of curvature are extremely low, that is smooth out the tight bends. This
will reduce the backwater effect and sediment deposition caused by these tight
bends and increase the overall channel gradient and sediment transport
capacity.
5. Log/boulder J -hooks, cross vanes, and toe wood will be installed at key locations
along the main stem Big Creek to reduce near -bank stress, provide grade
control, dissipate energy, and create habitat.
6. Long-term bank stabilization and lateral control will be provided by planting native
grasses, trees, and shrubs on the lower and upper stream banks.
7. An oxbow wetland will be created along the abandoned channel in the lower
section of the mainstem project area.
35

Big Creek IV Stream Restoration Design Report
8. A piped culvert crossing will be installed at the upstream end of the Tributary 1
project area. A ford crossing will be installed along the middle section of the
mainstem project area.
The restoration approach presented above is illustrated in the design drawings (i.e.,
plan view, profile, and cross-sections) attached to this report. The design criteria are
summarized in the Appendix to this report.
5.2. Design Criteria
52.1. Reference Reach Data
After determining the targeted stream types (i.e. stable form for the reaches to be
restored) for Big Creek, dimensionless ratios were taken from a reference reach data
base developed from stable B4c and C4 streams in the Piedmont and Mountain
Regions of North Carolina. The dimensionless ratios are presented in the Appendix to
this report.
5.2.2. Design Discharges
As noted in the Hydrology section of this report, three methods were used to develop
bankfull discharge estimates. These included 1) updated regional regression equations
developed in North Carolina (NCSU and NRCS, 1999); 2) TR -20 Hydrologic Model; and
3) Manning's equation and field data.
Based on this analysis it was determined that utilizing the Rural Regional Regression
estimates provided a reliable method for estimating bankfull discharge for the proposed
project design.
The bankfull discharges used during the design process for design points 1, 2, and 3
were 217.9 cfs, 223.3 cfs, and 234.6 cfs, respectively. These flows as well as the peak
discharge estimates for the 1-, 2-, 10-, 50-, and 100 -year storm events developed using
the TR -20 model provided input for the HEC -RAS hydraulic model.
5.2.3. Channel Geometry
Since aggradation is an on-going problem along Big Creek, one major objective of the
restoration project was to improve sediment transport competency and capacity. This
can generally be accomplished by adjusting channel cross-sectional dimensions and
channel slope. The design criteria included maximizing the overall channel gradient for
a given reach while maintaining a stable plan form.
The preliminary channel plan form layout was developed during several site walks and
sketched on the base maps. After the plan form was developed general concepts for the
layout of the longitudinal profile and the location of bed features were developed.
36

Big Creek IV Stream Restoration Design Report
After the proposed channel plan form and longitudinal profile were completed,
preliminary channel dimensions were developed utilizing the updated Bankfull
Discharge and Hydraulic Geometry Regional Regressions for the Rural Piedmont
Region of North Carolina (NCSU and NRCS, 2006) to determine channel cross-
sectional area (A) based on the drainage area to a given reach. The calculated A and
W/D ratios from our reference reach database were used to determine bankfull width
Wbf = �(Wbkf / dbkf) (Abkf) and bankfull mean depth Dbf = Wbkf / (Wbkf / dbkf).
The proposed slope, bankfull cross-sectional area, width, depth and width/depth ratios
were adjusted for each reach using an iterative process that included multiple sediment
entrainment analyses. After each adjustment the latest channel dimensions and profile
were checked against ratios from the reference reach database.
5.2.4. Sediment Entrainment Analysis
In restoration design, entrainment analysis is utilized to verify that the proposed channel
generates the shear stress needed to entrain and transport the sediment expected to be
moving through the project reach under bankfull flow conditions. Sediment data
gathered from riffle pavement/subpavement and point bar samples along the Big Creek
project reaches was utilized in the entrainment analysis to verify that the project channel
dimensions and profile are appropriate to maintain the competency of the restored
reaches.
A. Sediment Entrainment Analysis Procedures: Critical Dimensionless Shear Stress
Calculations
Using the following equations, the critical shear stress required to mobilize and transport
the largest particle from the bar sample is determined.
Determine ratio D5o/D50"
Where: D50 = bed material D50 of riffle
D50" = D50 of bar
If ratio is 3.0 — 7.0, calculate the critical shear stress using:
Tci = .0834 (D5o/D50^) -0.872
If ratio D5o/D50^ is not 3.0 — 7.0, calculate the ratio of Di/D50
Where: Di = largest particle from bar or riffle subpavement
D50 = bed material D50 of riffle (100 count in riffle)
If ratio of Di/D50 is 1.3 — 3.0, calculate the critical shear stress using:
Tci = .0384 (Di/D50) -0.887
37

Big Creek IV Stream Restoration
B. Big Creek Project Reaches
Design Report
Bulk sediment samples were collected along Big Creek. This effort included the
collection of point bar samples. Based on our experience on other design projects and
an analysis of the sediment sampling database those samples determined to be most
representative of Big Creek sediment transport conditions were used in the sediment
entrainment analysis to verify the competency of the proposed channel.
Calculate ratio of D5o/D50^
D50 = 45.7 mm (bed material D50)
D50" = 13.1 mm (bar sample D50)
D5o/D50^ = 45.7/13.1 = 3.5
If ratio is 3.0 — 7.0, calculate the critical shear stress using:
Tci = .0834 (D5o/D50^) -0.872
Calculate critical shear stress (Tci)
Tci = .0834 (D5o/D50") -0.872
Tci = .0834 (45.7/13.1) - 0.872
Tci = 0.028
C. Existing Conditions
The critical shear stress values developed in these analyses were compared to the
critical shear stress values calculated for riffle cross-sections along the existing
channels. As shown in Table 16 below, this comparison provided verification of field
observations regarding existing streambed stability and channel competency.
Table 16 — Existing
Conditions Sediment Entrainment Analysis
Existing
Required
Ratio
Existing
Mean
Mean
Existing
Geomorphic
Reach
Slope
Depth
Depth
Depth to
Condition
(ft/ft)
(ft)
(ft)
Required
Depth
MS
0.0029
2.67
4.0
0.7
Aggrading
Tributary #2
0.0032
1.99
3.5
0..6
Aggrading
D. Proposed Conditions
During the design phase of the project, the critical shear stress developed in these
analyses was utilized to verify that the project channel dimensions and profile are
appropriate to maintain the competency of the restored reaches.
38

Big Creek IV Stream Restoration
Design Report
Table 17 — Proposed Conditions
Sediment Entrainment
Analysis
Existing
Existing
Required
Ratio
Existing
Reach
Slope
Mean
Mean
Depth to
Geomorphic
(ft/ft)
Depth
Depth
Required
Condition
(ft)
(ft)
Depth
MS
0.0041
2.9
2.9
1.0
Stable
Tributary #2
0.0052
2.2
2.2
1.0
Stable
39

Big Creek IV Stream Restoration Design Report
REFERENCES
1. Earth Satellite Corporation (EarthSat) Land Use, 1997 — 2003.
2. National Oceanographic and Atmospheric Administration - National Climate Data
Center, Cooperative Station Data/Record Climatological Observations Website,
2004. Regional Precipitation, Snowfall, Temperature Records for Mount Airy, NC
1999 —2004.
3. North Carolina Division of Water Quality, 2008. Roanoke Basinwide Water
Quality Management Plan.
4. North Carolina Division of Water Quality, 2001. Standard Operating Procedures —
Biological Monitoring. Biological Assessment Unit. Raleigh, NC.
5. North Carolina Division of Water Quality, 2002. Basinwide Assessment Report —
Roanoke River Basin. Environmental Sciences Branch. Raleigh, NC.
6. North Carolina Department of Transportation GIS Database — River and Stream;
Road; and National Wetland Inventory (NWI) mapping layers.
7. North Carolina State University, Cooperative Extension Service and U.S.D.A.
Natural Resources Conservation Service, 2006. Hydraulic Geometry
Relationships for the Rural Piedmont of North Carolina. Raleigh, N.C.
8. Rosgen, D.L., 1994. A Classification of Natural Rivers. Catena 22: 169-199.
9. Rosgen, D.L., 1996. Applied River Morphology. Wildland Hydrology. Pagosa
Springs, Colorado.
10. U.S. Department of Agriculture, Natural Resource Conservation Service, Surry
County, North Carolina — Historic Aerial Photograph Series 1936 - 1997.
11. U.S. Department of Agriculture, Natural Resource Conservation Service, Website
- Soil Survey for Surry County, North Carolina 2004.
12. U.S. Geological Survey 7.5 Minute Quadrangle Topographic Map for
Claudeville, Virginia.
13. U.S. Geological Survey 7.5 Minute Quadrangle Geologic Map for Pilot Mountain,
North Carolina.
14. U.S. Department of Agriculture, 1985, National Hydrologic Handbook, Section 4,
Hydrology: Soil Conservation Service, Washington, DC.
40

Big Creek IV Stream Restoration
Design Report
15. U.S. Department of Agriculture, 1992. Computer program for project formulation -
hydrology: SCS Technical Release 20, Washington, DC.
16. Hydrologic Engineering Center, 2010. HEC -RAS River Analysis System
Applications Guide, Version 4.1, Computer Program Document CPD -68, US
Army Corps of Engineers, Davis, CA.
17. U.S. Department of Agriculture, 2011. Web Soil Survey
http://websoilsurvey.nres.usda.gov/app/HomePage.htm, accessed June 2011.
41

APPENDIX A
Channel Morphology Data

Worksheet 5-3. Field form for Level Il stream classification (Rosgen, 1996; Rosgen and Silvey, 2005).
Stream:
Big Creek IV, Reach - Reach 1
Basin:
Drainage Area: 4352 acres 6.8 rrliz
Location:
Westfield, NC (Stokes County)
Twp.&Rge:
; Sec.&Qtr.: ;
Cross -Section Monuments (Lat./Long.): Lat 36.50361 1 Long 80.43028 Date: 41/23116
Observers:
T. Burchette, Rex Walker Valley Type: VIII(c)
Bankfull WIDTH (Wbkf)
WIDTH of the stream channel at bankfull stage elevation, in a riffle section. T27,22
Bankfull DEPTH (dbk0
Mean DEPTH of the stream channel cross-section, at bankfull stage elevation, in a
riffle section (dekf = A / Wbki). 2.67
Bankfull X -Section AREA (Abkf)
AREA of the stream channel cross-section, at bankfull stage elevation, in a riffle
section. 72.72
Width/Depth Ratio (Wbkf1 dbkr)
Bankfull WIDTH divided by bankfull mean DEPTH, in a riffle section. 10.19
Maximum DEPTH (dmbkf)
Maximum depth of the bankfull channel crass -section, or distance between the
bankfull stage and Thalweg elevations, in a riffle section. 3.85
flz
ft/ft
WIDTH of Floud -Prone Area (Wfpa)
Twice maximum DEPTH, or (2 x d,,bw) = the stagefelevation at which flood -prone
area WIDTH is determined in a riffle section. 200 f
Entrenchment Ratio (ER)
The ratio of flood -prone area WIDTH divided by bankfull channel WIDTH (Wfp;,l Weir)
(riffle section). 7.35
Channel Materials (Particle Size Index ) D50
The D50 particle size index represents the mean diameter of channel materials, as
sampled from the channel surface, between the bankfull stage and Thalweg
elevations.
23.45
Water Surface SLOPE (S)
Channel slope = "rise over run" for a reach approximately 20-30 bankfull channel
widths in length, with the "riffle -to -riffle" water surface slope representing the gradient
at bankfull stage. 0.0029
Channel SINUOSITY (k)
Sinuosity is an index of channel pattern, determined from a ratio of stream length
divided by valley length (SL / VL): or estimated from a ratio of valley slope divided by
channel slope (VS 1 S). 1.63
Stream E4f C4
(See Figure 2-14)
Typ e
Copyright C 2006 Wildland Hydrology Appendix A-1 WARSSS page 5-29

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Appendix A-3

River Name:
Reach Name:
Sample Name:
Survey Date:
Size (mm)
RIVERMGRPH PARTICLE SUMMARY
Big Creek Iv
Reach 1
classification
01/18/2016
pebble count
TOT # ITEM % cum %
0 - 0.062
0
0.00
0.00
0.062 - 0.125
0
0.00
0.00
0.125 - 0.25
8
8.00
8.00
0.25 - 0.50
12
12.00
20.00
0.50 - 1.0
12
12.00
32.00
1.0 - 2.0
1
1.00
33.00
2.0 4.0
1
1.00
34.00
4.0 - 5.7
4
4.00
38.00
5.7 - 8.0
0
0.00
38.00
8.0 - 11.3
3
3.00
41.00
11.3 - 16.0
5
5.00
46.00
16.0 - 22.6
3
3.00
49.00
22.6 - 32.0
11
11.00
60.00
32 - 45
14
14.00
74.00
45 - 64
15
15.00
89.00
64 -- 90
8
8.00
97.00
90 - 128
3
3.00
100.00
128 - 180
0
0.00
100.00
180 256
0
0.00
100.00
256 - 362
0
0.00
100.00
362 - 512
0
0.00
100.00
512 - 1024
0
0.00
100.00
1024 - 2048
0
0.00
100.00
Bedrock
0
0.00
100.00
D16 (mm)
0.42
D35 (mm)
4.42
X50 (mm)
23.45
D84 (mm)
57.67
D95 (mm)
83.5
D100 (mm)
128
Silt/clay
0
Sand (%)
33
Gravel (%)
56
cobble (%)
11
Boulder M
0
Bedrock M
0
Total Particles = 100.
Appendix A-4

River Name:
Reach Name:
Sample Name:
Survey Date:
Si ze (mm)
RIVERMORPN PARTICLE SUMMARY
Big creek
Reach 1
riffle 100
01/18/2016
IV
pebble count
TOT # ITEM % cum %
0 - 0.062
0
0.00
0.00
0.062 - 0.125
0
0.00
0.00
0.125 - 0.25
0
0.00
0.00
0.25 - 0.50
0
0.00
0.00
0.50 - 1.0
2
1.96
1.96
1.0 - 2.0
0
0.00
1.96
2.0 - 4.0
0
0.00
1.96
4.0 - 5.7
1
0.98
2.94
5.7 -- 8.0
0
0.00
2.94
8.0 - 11.3
6
5.88
8.82
11.3 - 16.0
6
5.88
14.71
16.0 - 22.6
9
8.82
23.53
22.6 - 32.0
15
14.71
38.24
32 - 45
27
26.47
64.71
45 - 64
24
23.53
88.24
64 90
11
10.78
99.02
90 - 128
1
0.98
100.00
128 - 180
0
0.00
100.00
180 - 2.56
0
0.00
100.00
256 - 362
0
0.00
100.00
362 512
0
0.00
100.00
512 - 1024
0
0.00
100.00
1024 - 2048
0
0.00
100.00
Bedrock
0
0.00
100.00
D16 (mm)
16.97
D35 (mm)
29.93
D50 (mm)
37.78
D84 (mm)
60.58
D95 (mm)
80.3
D100 (mm)
128
silt/clay (%)
0
Sand (%)
1.96
Gravel (%)
86.28
cobble (%)
11.76
Boulder (/)
0
Bedrock (%)
0
Total Particles = 102.
Appendix A-5

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Entrainment Calculation Form
Stream: Pig Creel: 4
Value
l _caclg: Proposed -
Date:
0.030
Observers:
Critical Dimensionless Shear Stress
Critical Dimensionless Shear Stress
tj = 0.0834(d-ldso)-1.872
Di (ft)
Largest particle from bar sample
Value
Variable
Definition
37.78
di (mm)
D50 Bed Material (D50 from riffle pebble count)
11,74
dip (imam)
Bar Sample D5© or Sub -pavement D50
0.0301
tci
Critical Dimensionless Shear Stress
Bankfull Mean Depth Required for Entrainment of Largest Particle in Bar Sample:
d,. = (t�,*1.65*D�/S.
1.65 = submerged specific weight of sediment
Value
Variable
Def nition
0.030
tai
Critical Dimensionless Shear Stress
0.236
Di (ft)
Largest particle from bar sample
0.0041
S, (ft/ft)
Proposed Bankfull Water Surface Slope
2.9
dr (ft)
Bankfull Mean Depth Required
2.9
de (ft)
Proposed Bankfull ll+'Lean Depth (from, riffle cross section)
1.0
de/dr
Ratio of Existing Mean Depth to Required Mean Depth
Check one: E Stable (de/dr a 1) Ej Aggrading (de/dr a 1) Degrading (de/dr > 1)
Bankfull Water Surface Slope Required for Entrainment of Largest Particle in Bar Sample:
Sr = (tri*1,65*D;}/d,
1.65 = submerged specific weight of sediment
Value
Variable
Definition
0.030
"�i
Critical Dimensionless Shear Stress
0.236
DI (ft)
Largest particle from bar sample
2.9
de (ft)
Proposed Bankfull Mean Depth (front riffle cross section)
0.0040
Sr (ft/ft)
Bankfull Water Surface Slope Required
1.0
S,/Sr
Ratio of Existing Slope to Required Slope
Check one: R] Stable (5e/sr = 1) [1 Aggrading (Se/Sr < 1) [j Degrading (Se/Sr > 1)
Sediment Transport Validation
72
I-argest Particle in Bar Sample Di (mm)
IT
Hydraulic Radius (ft)
0.69
Bankfull Shear Stress t,=gRS (lb/ft) g = 612.4 R=Hydraulic Radius S=Slope
325
Moveable particle size (min) at bankfulI shear stress (predicted by the Shields Diagram:
Blue field bogie: p238, Red field book.: 190)
2.1
Predicted shear stress required to initiate movement of D; (mm) (see Shields Diagram:
Blue field book: p238, Red field book: 190)
After Wildland Hydrology 2001
Appendix A-7

Worksheet 6-3. Field form for Level 11 stream classification (Rosgen, 1996; Rosgen and Silvey, 2005).
Stream: Big Creek 4 Trib., Reach - Reach 1
Basin: Drainage Area: 2432 acres 3.8 mit
Location: Westfield, NC (Stokes County)
Twp.&Rge: ; Sec.&©tr.: ;
Cross -Section Monuments (Lat./Long.): 36.5035 Lat 1-80.4302 Long Date: 01/23/16
Observers: T. Burchette, Rex Walker Valley Type: Vlll(c)
Bankfull WIDTH (Wekf)
WIDTH of the stream channel at bankfull stage elevation, in a riffle section. 20.6 if
Bankfull DEPTH (dbkf)
Mean DEPTH of the stream channel cross-section, at bankfull stage elevation, in a
riffle section (dbkf= A ! Wbld). 1.99
Bankfull X -Section AREA (Abkf)
AREA of the stream channel cross-section, at bankfull stage elevation, in a riffle
section.
41.09
Width/Depth Ratio (Wb/ dbkf)
Bankfull WIDTH divided by bankfull mean DEPTH, in a riffle section. 10.35
Maximum DEPTH (dmbkf)
Maximum depth of the bankfull channel cross-section, or distance between the
bankfull stage and Thalweg elevations, in a riffle section. 2.73
ft2
f#lft
WIDTH of Flood -Prone Area (Wfp,)
Twice maximum DEPTH, or (2 x d.1,11) = the stage/elevation at which flood -prone
area WIDTH is determined in a riffle section. 46 f
Entrenchment Ratio (ER)
The ratio of flood -prone area WIDTH divided by bankfull channel WIDTH (Wfpa1 WNd)
(riffle section). 2.23
Channel Materials (Particle Size Index ) D50
The D50 particle size index represents the mean diameter of channel materials, as
sampled from the channel surface, between the bankfull stage and Thalweg
elevations. 1.26
Water Surface SLOPE (S)
Channel slope ='rise over run" for a reach approximately 20-30 bankfull channel
widths in length, with the "riffle-to-riffie" water surface slope representing the gradient
at bankfull stage.
(}.0032
Channel SINUOSITY (k)
Sinuosity is an index of channel pattem, determined from a ratio of stream length
divided by valley length (SL f VL); or estimated from a ratio of valley slope divided by
channel slope (VS 1 S).
1.12
Stream B514C
Type {See Figure 2-14}
Copyright @ 2006 W ldland Hydrology
Appendix A-8
MITI
WARSSS page 5-29

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V) wQ}(Vi-0CL0tULn0)=Q7
V) r-r-04JC0CVMU00L.-PCD
rd r- r E M rd 0 (Z +J C V) r- 04-)-a V)
r � M :3 -r- QJ P-= M'r•r L. C.r 0
L,J >>Z3YLLU300>uw31. w
Appendix A-9
4-
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Appendix A-9

W
h
r--1
20-j
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li
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m
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Appendix A-10
CD
N
'C
m
-5r-�0-
Vn
L
0
N
0
no

River Name.
Reach Name:
Sample Name
Survey Date:
Size (mm)
RIVERMORPH PARTICLE SUMMARY
Big Creek 4 Trib.
Reach 1
classification
01/19/2016
pebble count
TOT # ITEM % CUM %
0 - 0.062
0
0.00
0.00
0.062 - 0.125
0
0.00
0.00
0.125 - 0.25
0
0.00
0.00
0.25 - 0.50
0
0.00
0.00
0.50 - 1.0
43
43.00
43.00
1.0 - 2.0
27
27.00
70.00
2.0 - 4.0
1
1.00
71.00
4.0 - 5.7
2
2.00
73.00
5.7 - 8.0
l
1.00
74.00
8.0 - 11.3
2
2.00
76.00
11.3 - 16.0
2
2.00
78.00
15.0 - 22.6
4
4.00
82.00
22.6 32.0
5
5.00
87.00
32 - 45
5
5.00
92.00
45 - 64
6
6.00
98.00
64 - 90
1
1.00
99.00
90 - 128
1
1.00
100.00
128 - 180
0
0.00
100.00
180 256
0
0.00
100.00
256 - 362
0
0.00
100.00
362 - 512
0
0.00
100.00
512 - 1024
0
0.00
100.00
1024 - 2048
0
0.00
100.00
Bedrock
0
0.00
100.00
D16 (mm)
0.69
D35 (mm)
0.91
D50 (mm)
1.25
D84 (mm)
26.35
D95 (mm)
54.5
D100 (mm)
128
silt/clay ()
0
Sand (%)
70
Gravel [%)
28
Cobble (/)
2
Boulder [%)
0
Bedrock [%)
0
Total Parti cl es = 100.
Appendix A-11

River Name:
Reach Name:
Sample Name:
Survey Date:
size (mm)
RIVERMORPH PARTICLE SUMMARY
Big Creek
Reach 1
Riffle 100
01/18/2016
4 Trib.
Count
TOT # ITEM % CUM %
0 - 0.062
0
0.00
0.00
0.062 - 0.125
0
0.00
0.00
0.125 - 0.25
0
0.00
0.00
0.25 - 0.50
0
0.00
0.00
0.50 - 1.0
0
0.00
0.00
1.0 - 2.0
0
0.00
0.00
2.0 - 4.0
1
1.00
1.00
4.0 - 5.7
1
1.00
2.00
5.7 - 8.0
1
1.00
3.00
8.0 - 11.3
4
4.00
7.00
11.3 - 16.0
5
5.00
1.2.00
16.0 - 22.6
15
15.00
27.00
22.6 - 32.0
14
14.00
41.00
32 - 45
24
24.00
65.00
45 - 64
26
26.00
91.00
64 - 90
7
7.00
98.00
90 - 128
2
2.00
100.00
128 180
0
0.00
100.00
180 - 256
0
0.00
100.00
256 - 362
0
0.00
100.00
362 - 512
0
0.00
100.00
512 - 1024
0
0.00
100.00
1024 - 2048
0
0.00
100.00
Bedrock,
0
0.00
100.00
D16 (mm)
17.76
D35 (mm)
27.97
D50 (mm)
36.88
D84 (mm)
58.88
D95 (mm)
78.86
D100 (mm)
128
Silt/Clay (%)
0
sand (%)
0
Gravel (%)
91
Cobble (%)
9
Boulder (%)
0
Bedrock (%)
0
Total Particles = 100.
Appendix A-12

2
a
0
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Appendix A-13
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Appendix A-14

Entrainment Calculation Form
Stream: Bib Creek 4 Tributary 2
Reach: Proposed
Date:
Observers:
Critical Dimensionless Shear Stress
ki = 0.0834(dild5u)-o.$72
tCi
Value
Variable
Definition
36.88
di (mm)
D50 Bed Material (D50 from riffle pebble count)
1.0.95
dso (mm)
Bar Sample D50 or Sub -pavement D50
0.029
tC1
Critical Dimensionless Shear Stress
Bankfull Mean Depth Required for Entrainment of Largest Particle in Bar Sample:
dr = (k.*1.65*DJ/St
1.615 = submerged specific weight of sediment
Value
Variable
Definition
0.029
tCi
Critical Dimensionless Shear Stress
0.235
Di (ft)
Largest particle from bar sample
0.0052
Se (ftlft)
Proposed Bankfull Water Surface Slope
2.2
d,. (ft)
Bankfull Mean Depth Required
2.2
de (ft)
Proposed Bankfull Mean Depth (from riffle cross section)
1.0
d,/d,
Ratio of Existing Mean Depth to Required Mean Depth
Check one: Stable (de/dr = 1) Aggrading (de/dr ¢ 1) Degrading (de/dr > 1)
Bankfull Water Surface Slope Required for Entrainment of Largest Particle in Bar Sample:
S, = (t6*1.65*1)JIdE
1.65 =submerged specific weight of sediment
Value
Variable
Definition
0.029
tai
Critical Dimensionless Shear Stress
0.236
Di (ft)
Largest particle from bar sample
2.2
de (ft)
Proposed Bankfull Mean Depth (from riffle cross section)
0.+0051
Sr (ft/ft)
Bankfull Water Surface Slope Required
1.0
SIS,
Ratio of Existing Slope to Required Slope
Check One: [�] Stable (se/sr = 1) D Aggrading (Se/Sr t 1) [] Degrading (Se/Sr > 1)
Sediment Transport Validation
72
largest Particle in Bar Sample Di (mm)
1.9
Hydraulic Radius (ft)
0.62
Bankfull Shear Stress tG=gRS (lb&) g = 62.4 R=Hydraulic Radius S=Slope
51.3
Moveable particle size (mm) at bankfull shear stress (predicted by the Shields Diagram:
Blue field book: p238, Red field book. pI90
4.93
3'redicted shear stress required to initiate movement of Di (mm) (see Shields Diagram:
Slue field book: p238, Red field book: p 190)
Appendix A-15

APPENDIX B
Hydrology and Hydraulic Analysis
Supporting Documentation

BIG CREEK IV STREAM RESTORATION
HYDROLOGIC & HYDRAULIC STUDY
AUGUST 2016
Prepared by:
Ca
and
----- Consultants & Designers, Inc.
`Integrating Engineering and Environment
7455 New Ridge Road, Suite T Phone: [phone]
Hanover, Maryland 21076 Fax: [phone]
Website: www.baylandinc.com
Appendix B-1

Big Creek IV Stream Restoration
Hydrologic and Hydraulic Study August 2016
TABLE OF CONTENTS
INTRODUCTION..................................................................................................1
1.1. TOPOGRAPHIC AND LAND USE DATA.................................................1
1.2. SOIL CLASSIFICATION...........................................................................1
2. HYDROLOGIC MODEL....................................................................................... 2
2.1. REGIONAL REGRESSION EQUATIONS.................................................3
2.2. CALIBRATION OF HYDROLOGIC MODEL.............................................4
3. HYDROLOGIC RESULTS................................................................................... 6
4. HYDRAULIC MODEL.......................................................................................... 8
4.1. HYDRAULIC ANALYSIS REPORT...........................................................9
4.2. HYDRAULIC RESULTS..........................................................................14
5. REFERENCES...................................................................................................15
LIST OF TABLES
Table 1 —Watershed
Land Use....................................................................................... 1
Table2 —
Soil Coverage.................................................................................................. 2
Table 3 -
Sub -Basins Drainage Area Characteristics...................................................... 2
Table 4 —
Restoration Reach Study Points...................................................................... 3
Table 5 —
TR -20 Calibration for Multiple Storm Frequency Models ................................. 4
Table 6 —
TR -20 Precipitation Input................................................................................. 5
Table 7 —
Calibrated TR -20 Peak Discharges................................................................ 6
Table 8 —
Peak Discharge Comparison: SP01................................................................ 6
Table 9 —
Peak Discharge Comparison: SP02................................................................ 6
Table 10
— Peak Discharge Comparison: SP03.............................................................. 6
Table 11
- Existing and Proposed River Stationing Descriptions .................................... 8
Table 12
— Peak Discharge Flow Change Locations.......................................................
8
Table 13
- Existing and Proposed Manning's Values ...................................................... 9
Table 14
- 1 -YR Hydraulic Analysis Big Creek IV & Tributaries #1 and #2 ....................
10
Table 15
- 2 -YR Hydraulic Analysis Big Creek IV & Tributaries #1 and #2 ....................
11
Table 16
- 10 -YR Hydraulic Analysis Big Creek IV & Tributaries #1 and #2 ..................
12
Table 17
- 100 -YR Hydraulic Analysis Big Creek IV & Tributaries #1 and #2 ................
13
/_1» 4 I 10 191 1
Appendix A —
NRCS Soils/Land Use
Appendix B —
Hydrologic Models
Appendix C
— Regional Regression Equations
Appendix D
— Hydraulic Model and Results
Appendix E —
Drainage Area Map
BayLand Consultants & Designers, Inc.
Appendix B-2

Big Creek IV Stream Restoration
Hydrologic and Hydraulic Study August 2016
Appendix F — HEC -RAS Cross Section Map
Appendix G — 100 -Year Floodplain Map
BayLand Consultants & Designers, Inc.
Appendix B-3

Big Creek IV Stream Restoration
Hydrologic and Hydraulic Study August 2016
INTRODUCTION
This report details the existing and proposed hydrologic and hydraulic analyses of Big
Creek in Surry & Stokes County, North Carolina. The proposed associated stream
restoration project is the fourth phase of the Big Creek Stream Restoration. The first,
second, and third phases were completed in October 2008, May 2013, and December
2014 respectively. The portion of Big Creek that is under investigation begins
approximately 4,100 feet downstream of Albion Church Road crossing and continues for
another 2,000 feet downstream toward the Asbury Road crossing. The existing channel
and two tributaries will be restored to a natural channel by mitigating damage and
encroachment of agricultural use. The proposed restoration will utilize the following
hydrologic and hydraulic analysis to design a channel with geomorphological
characteristics that are representative of a stable stream.
1.1. TOPOGRAPHIC AND LAND USE DATA
Topographic and land use data were compiled from a combination of field survey, aerial
photogrammetry, and published data. Field topographic data was collected during the
December of 2015 by Big Eagle Survey Inc. Land use data was derived with a
combination of the latest aerial photography and the Web Soil Survey soil data. The
published data included the Stokes County 2007 GIS data. Due to the relative age of
the GIS data, desktop analysis was required to check the accuracy and validity of the
data. The collected topographic data was compiled into a single file to establish a base
for analysis of existing conditions. Table 1 shows the land use breakdown for each sub -
basin within the restoration phase.
1.2. SOIL CLASSIFICATION
Using the NRCS Hydrologic Soil Classification system, soils can be classified according
to their ability to decrease surface runoff through infiltration. The classification ranges
from Hydrologic Soil Group (HSG) A which is characterized by high infiltration rates and
a low potential for surface runoff, to HSG D which is characterized by low infiltration
rates and high surface runoff potential. Hydrologic Soil Classifications for the project
area were obtained through the USDA online soil survey website. A soil classification
BayLand Consultants & Designers, Inc.
Appendix B-4
Watershed
Land Use
Sub -Basin
Impervious
Acres
Impervious
%
Forest
Acres
Forest
%
Open
Acres
Open
Big Creek III
114.7
2.8
2527.1
60.7
1522.8
36.5
Big Creek IV -A
0.3
0.7
23.9
53.7
19.4
43.6
Big Creek IV -B
0.6
2.2
15.2
54.5
12.1
43.4
Big Creek
Tributary #1
0.3
0.4
59.9
81.5
13.3
18.1
Big Creek
Tributary #2
58.9
2.4
1728.4
71.2
642.1
26.4
Total
174.8
2.6
4354.5
64.6
2209.7
32.8
1.2. SOIL CLASSIFICATION
Using the NRCS Hydrologic Soil Classification system, soils can be classified according
to their ability to decrease surface runoff through infiltration. The classification ranges
from Hydrologic Soil Group (HSG) A which is characterized by high infiltration rates and
a low potential for surface runoff, to HSG D which is characterized by low infiltration
rates and high surface runoff potential. Hydrologic Soil Classifications for the project
area were obtained through the USDA online soil survey website. A soil classification
BayLand Consultants & Designers, Inc.
Appendix B-4

Big Creek IV Stream Restoration
Hydrologic and Hydraulic Study August 2016
analysis detailing the types and percentages of each soil group for the 5 sub -basins can
be found in Appendix A. Table 2 presents the abundance and percentage of each HSG
within the project area. Big Creek and its tributaries consisted predominantly of HSG B
type soils which are characterized by moderate infiltration rates and average runoff
potential.
2. HYDROLOGIC MODEL
The Big Creek watershed delineation was expanded from previous work completed for
the first, second, and third phases of the Big Creek Restoration. The hydrologic model
was expanded to include the drainage area to the limit of the fourth phase of restoration,
which included four (4) new sub -drainage areas. The USDA Soil Conservation Service
SCS TR -55 computer program was used to compute the runoff curve number (RCN)
and time of concentration (Tc). The resulting RCN and Tc were incorporated into
Technical Release No. 20: Computer Program for Project Formulation Hydrology JR -
20), based upon Soil Conservation Service methodology. Peak discharges for the
existing drainage areas were computed with all computations assuming good hydrologic
conditions. Table 3 lists the delineated sub -basins along with their corresponding area,
runoff curve number, and time of concentration.
Table 3 - Sub
-Basins
Table ..-
Characteristics
Sub -Basin
Area
(Acres)
Basin
A
Acres
A
%
B
Acres
B
%
C
Acres
C
%
D
Acres
D
Big Creek III
192.2
4.6
3780.3
90.8
192.1
4.6
6.8
0.2
Big Creek IV -A
0
0
33
74.1
11.5
25.9
0
0
Big Creek IV -13
0
0
17.4
62.5
10.5
37.5
0
0
Big Creek
Tributary #1
0
0
73.5
100.0
0
0
0
0
Big Creek
Tributary #2
78.9
3.3
1417.7
58.5
621.5
38.0
6.5
0.2
Total
271.1
4.0
5321.9
79.1
1135.6
16.9
13.3
0.2
2. HYDROLOGIC MODEL
The Big Creek watershed delineation was expanded from previous work completed for
the first, second, and third phases of the Big Creek Restoration. The hydrologic model
was expanded to include the drainage area to the limit of the fourth phase of restoration,
which included four (4) new sub -drainage areas. The USDA Soil Conservation Service
SCS TR -55 computer program was used to compute the runoff curve number (RCN)
and time of concentration (Tc). The resulting RCN and Tc were incorporated into
Technical Release No. 20: Computer Program for Project Formulation Hydrology JR -
20), based upon Soil Conservation Service methodology. Peak discharges for the
existing drainage areas were computed with all computations assuming good hydrologic
conditions. Table 3 lists the delineated sub -basins along with their corresponding area,
runoff curve number, and time of concentration.
Table 3 - Sub
-Basins
Drainage Area
Characteristics
Sub -Basin
Area
(Acres)
Area
(Square
Miles)
Runoff
Curve
Number
RCN
Time of
Concentration
(Hours)
Big Creek III
4164.6
6.51
58
2.513
Big Creek IV -A
44.5
0.07
62
0.642
Big Creek IV -B
27.9
0.04
64
0.468
Big Creek Tributary #1
73.5
0.11
56
0.411
Big Creek Tributary #2
2427.7
3.79
62
1.538
2 BayLand Consultants & Designers, Inc.
Appendix B-5

Big Creek IV Stream Restoration
Hydrologic and Hydraulic Study August 2016
Along with the watershed sub -basins, study points were selected for the restoration
reaches to provide accurate peak discharge estimates for the proposed restoration
project. Where the overlying watershed hydrology warranted, additional delineations
were provided at the transitions of the selected restoration reaches. Table 4 shows the
computed areas and associated impervious area percentages for each of the proposed
restoration reach study points.
Table-
Points
Cumulative
Cumulative
Impervious
Sub -Basins
Study Point /
Area
Area
Area (%)
Reach ID
(Acres)
(Square
Miles
SP01
4165
6.51
2.8
Big Creek III
Big Creek III,
SP02
4284
6.69
2.7
Big Creek IV -A,
Tributary #1
SP03
6729
10.51
2.7
All
The SCS Technical Release 20 (TR -20) computer program was used to determine peak
discharges at the selected study points for different storm events by routing the rainfall
runoff through the preexisting channel. The amount of runoff and the speed at which it
reached the study points determined the peak discharge and is a function of the land
use, soil type, basin size and shape, and pre -storm soil moisture. The TR -20 model is a
deterministic hydrologic model that synthesizes a single event runoff hydrograph as a
function of a rainfall input and drainage area characteristics. Rainfall depths and
distributions for the 1 to 100 year 24-hour storm events were obtained from the National
Oceanic and Atmospheric Administration (NOAA) Atlas 14's Mount Airy, North Carolina
station. The model operates using time varying rainfall to produce a hydrograph that
simulates the role of the watershed area, land cover, hydrologic soil types, antecedent
runoff conditions, topography, storage basins, the characteristics of the overland,
shallow confined, and channel flow paths, and storage attenuation such as that created
by flood plains, wetlands, structures, and ponds. The hydrologic model was calibrated
as described within the Calibration of the Hydrologic Model section of this report. The
full hydrologic model can be found in Appendix B.
2.1. REGIONAL REGRESSION EQUATIONS
Regression equations were developed to allow interpolation of hydrologic data from
gauged to ungauged sites within North Carolina. This allows estimates of peak
discharge to be made on ungauged streams and rivers. Five distinct physiographic
regions were identified (Blue Ridge, Piedmont, Sand Hills, Southeastern Plains, and
Middle Atlantic Coastal Plain) and regression equations were developed for each
region. The Big Creek Stream Restoration Project is located within the Piedmont region.
Regression analysis is useful in determining whether the hydrologic model has been
sufficiently calibrated to provide the most accurate estimate of peak discharges for the
3 BayLand Consultants & Designers, Inc.
Appendix B-6

Big Creek IV Stream Restoration
Hydrologic and Hydraulic Study August 2016
reach. Regional regression equations from Scientific Investigations Report 2009-5158
"Magnitude and Frequency of Rural Floods in the Southeastern United States, through
2006: Volume 2, North Carolina" by the U.S. Geological Survey, dated 2009 were
employed to analyze the calibrated peak discharges of the hydrologic model. The
hydrologic model was considered successfully calibrated if the peak discharges were
within one standard error of the regional regression peak discharge estimates.
Appendix C list the NC USGS regional regression equations used to determine the
success of the hydrologic model calibration.
2.2, CALIBRATION OF HYDROLOGIC MODEL
The TR -20 hydrologic model developed for this project was calibrated by adjusting the
drainage area characteristics and inputs such as the antecedent runoff condition (ARC)
and the rainfall distribution. Calibration is necessary because the TR -20 modeling
software has been shown to over predict peak flows for all return periods. Regional
regression equations were used to provide a baseline for the calibration because they
were developed using flow data from stream gauges which provide an indication of the
current drainage characteristics of the watershed. Table 5 lists the TR -20 input
elements and the application for calibration based on multiple storm frequency models.
Tablei Calibration for Multiple Storm Frequency.. -
Input Element /
Application
Calibration Variable
Drainage Area
Same for all storms
Time of Concentration
Same for all storms
variables
RCN conditions
Same for all storms
Reach Length
May increase for greater return periods but not
reverse
Dimensionless Unit
Same for all storms
Hydrograph
Rainfall Table — 24 -hr
Use for 25 -yr to 500 -yr storms
duration
Rainfall Table — 12 -hr
May use for the 2 through 10 -yr storms.
duration
Rainfall Table — 6 -hr
May use for 2, 5 and 10 -yr storms.
duration
Use 2 for 25 -yr and greater return period storms.
May use <2 for the 2 -yr to 10 -yr storms provided
ARC (Antecedent Runoff
that it does not decrease for greater return period
Condition)
storms. ARC of >2 may be considered for storms of
200+ -yrs providing that it does not decrease with
greater return period storms
4 BayLand Consultants & Designers, Inc.
Appendix B-7

Big Creek IV Stream Restoration
Hydrologic and Hydraulic Study August 2016
The antecedent runoff condition (ARC) is a measure of the soil moisture directly before
a storm event. Typical values range from 1-3 with 1 representing dry soil conditions and
3 representing wet soil conditions. An ARC value of 2 represents the preliminary wetting
of the ground surface and the filling of small depressions and is appropriate for severe
storm events (10 to 100 year) because they are typically related to longer cyclonic
events. An ARC value of 1 is more appropriate for short duration, summer thunder
storms which generally occur with the more frequent 1 to10 year storm events. The TR -
20 program only accepts integer ARC values; therefore, one calibration method is to
recalculate the RCN based on a fractional ARC value. This is most appropriate for
shorter return period storms (1 to 10 years). The equations for recalculating the RCN
are presented below.
For ARC <_ 2: RCN(x) _
For ARC >_ 2: RCN(x) _
[10+5.8(x-2)]RCN2
10+0.13(x-2)RCN2
[10+13(X-2)]RCN2
10+0.13(x-2)RCN2
Where x = ARC value and is a real number between 1 and 3 and RCN2 is the pre -
calibrated RCN of the drainage area.
The model was calibrated by selecting a fractional ARC value and calculating the
corresponding RCN. This RCN value was input into the TR -20 model and a peak
discharge was calculated. If the TR -20 peak discharge did not fall within one standard
error of the peak discharge determined using the regional regression equations, then a
new fractional ARC was chosen and the corresponding RCN value was input into TR -
20. This process continued until the TR -20 peak discharge fell within one standard error
of the peak discharge from the regional regression equation. Table 6 lists the calibrated
inputs used for the various storm events for each drainage area and Table 7 lists the
computed calibrated peak discharges for each study point.
5 BayLand Consultants & Designers, Inc.
Appendix B-8
Table
Rainfall Distribution Rainfall
(Inches)
Storm Event
Selected
ARC
1 -YR
24 -hr NOAA C
3.00
2.0
2 -YR
24 -hr NOAA C
3.64
2.0
5 -YR
24 -hr NOAA C
4.64
2.0
10 -YR
24 -hr NOAA C
5.47
2.0
25 -YR
24 -hr NOAA C
6.66
2.0
50 -YR
24 -hr NOAA C
7.67
2.0
100 -YR
24 -hr NOAA C
8.76
2.0
5 BayLand Consultants & Designers, Inc.
Appendix B-8

Big Creek IV Stream Restoration
Hydrologic and Hydraulic Study August 2016
3. HYDROLOGIC RESULTS
Tables 8 through 10 compare the regional regression equations with the calibrated TR -
20 Peak Discharges to determine whether the calibration was successful in achieving
the target values within one standard error of the regional regression equations.
Table.
..
-.TR-20
Peak .-
Storm
Study Point
7
1 -YR
cfs
2 -YR
cfs
5 -YR
cfs
10 -YR
cfs
25 -YR 50 -YR
cfs cfs
100 -YR
cfs
SP01
191.1
418.6
908.2
1394.9
2171.4 2876.9
3630.7
SP02
194.6
424.0
919.1
1409.9
2197.1 2906.8
3662.8
SP03
375.6
790.6
1664.1
2512.0
3843.3 5024.1
6270.0
3. HYDROLOGIC RESULTS
Tables 8 through 10 compare the regional regression equations with the calibrated TR -
20 Peak Discharges to determine whether the calibration was successful in achieving
the target values within one standard error of the regional regression equations.
6 BayLand Consultants & Designers, Inc.
Appendix B-9
Table.-
..
..
-i
Storm
Storm
Regression
Lower
Lower
Upper
TR -20
Recurrence
peak
Standard
Limit
Limit
peak
Interval (yrs)
Discharge
Error (%)
(cfs)
(cfs)
Discharge
cfs
(cfs)
cfs
cfs
(cfs)
2
533
34.5%
349
717
418.6
5
955
41.2%
561
1348
908.2
10
1264
35.1%
820
1708
1394.9
50
2033
39.6%
1228
2839
2876.9
100
2361
41.9%
1371
3350
3630.7
6 BayLand Consultants & Designers, Inc.
Appendix B-9
Table.-
..
-i
Storm
Storm
Regression
Lower
Lower
Upper
TR -20
Recurrence
peak
Standard
Limit
Limit
peak
Interval (yrs)
Discharge
Error (%)
(cfs)
(cfs)
Discharge
cfs
cfs
cfs
cfs
2
543
34.5%
355
730
424.0
5
972
41.2%
571
1372
919.1
10
1286
35.1%
835
1738
1409.9
50
2068
39.6%
1249
2887
2906.8
100
2401
41.9%
1395
3406
3662.8
6 BayLand Consultants & Designers, Inc.
Appendix B-9
DischargeTable 10 - Peak
•. -0
Storm
Regression
Lower
Upper
TR -20
Recurrence
peak
Standard
Limit
Limit
Peak
Interval (yrs)
Discharge
Error (%)
(cfs)
(cfs)
Discharge
cfs
cfs
2
727
34.5%
476
978
790.6
5
1290
41.2%
758
1821
1664.1
10
1699
35.1%
1103
2296
2512.0
50
2712
39.6%
1638
3786
5024.1
6 BayLand Consultants & Designers, Inc.
Appendix B-9

Big Creek IV Stream Restoration
Hydrologic and Hydraulic Study August 2016
The TR -20 peak discharges were successfully calibrated for the more frequent 2
through 10 -year storm events for all study points, while the 50 and 100 -year storm
events were slightly above the upper regression limits for SP01 and SP02. The TR -20
discharges for the 50 and 100 -year events for SP03 were well above the upper limit of
the regression equation. One explanation is that the drainage area was subdivided into
four areas, and the hydrograph peaks for the two largest drainage basins coincided,
producing a larger peak discharge than predicted by the regression equations which do
not take into account routing of multiple drainage basins. Notwithstanding the 50 and
100 -year storms being outside the calibration window for all three study points, no
further calibration was performed. This is because the more frequent storm events (2-10
year) which are typically used in stream design were successfully calibrated, and that
the larger, less frequent storm events are most likely outside the calibration limits due to
the subdivision of the watershed and the inability of the regression equations to take
into account channel routing.
7 BayLand Consultants & Designers, Inc.
Appendix B-10
Storm
Regression
Lower
Upper
TR -20
Recurrence
Peak
Standard
Limit
Limit
Peak
Interval (yrs)
Discharge
Error (%)
(cfs)
(cfs)
Discharge
cfs
cfs
100
3139
41.9%
1824
4454
6270.0
The TR -20 peak discharges were successfully calibrated for the more frequent 2
through 10 -year storm events for all study points, while the 50 and 100 -year storm
events were slightly above the upper regression limits for SP01 and SP02. The TR -20
discharges for the 50 and 100 -year events for SP03 were well above the upper limit of
the regression equation. One explanation is that the drainage area was subdivided into
four areas, and the hydrograph peaks for the two largest drainage basins coincided,
producing a larger peak discharge than predicted by the regression equations which do
not take into account routing of multiple drainage basins. Notwithstanding the 50 and
100 -year storms being outside the calibration window for all three study points, no
further calibration was performed. This is because the more frequent storm events (2-10
year) which are typically used in stream design were successfully calibrated, and that
the larger, less frequent storm events are most likely outside the calibration limits due to
the subdivision of the watershed and the inability of the regression equations to take
into account channel routing.
7 BayLand Consultants & Designers, Inc.
Appendix B-10

Big Creek IV Stream Restoration
Hydrologic and Hydraulic Study August 2016
4. HYDRAULIC MODEL
HEC -RAS version 5.0.1 River Analysis System, developed by the U.S. Army Corps of
Engineers, was used to establish the water surface, velocity, and channel shear
stresses for the Big Creek Stream Restoration Project existing and proposed conditions.
Table 11 describes the hydraulic cross sections for Big Creek IV and its two tributaries
TableProposed River Stationing Descriptions
Big Creek IV & Tributaries #1 and #2
River Description
7
Stations
Big Creek
20.5-
Existing: Upstream Limits of Study
20.7
Proposed: No Changes
7-20
Existing: Mid Reach Cross Sections
191.1
Proposed: Natural Channel Design Sections — XS1 through XS20
0.1-0.5
Existing: Downstream Limits of Study
6
Proposed: No Changes
Tributary #1
1409.9
Existing: Tributary #1 Cross Sections
1-2
Proposed: Natural Channel Design Section — TRIB #1 XS1 through
790.6
XS2
Tributary #2
Existing: Tributary #2 Cross Sections
1-5
Proposed: Natural Channel Design Section — TRIB #2 XS 1 through
XS5
Table 12 identifies the developed study point peak discharges with the associated cross
section hydraulic models flow change locations.
Table.-
River Station
1 -YR
cfs
Flow Change
All Reaches
2 -YR
cfs)
Locations
10 -YR
(cfs)
100 -YR
(cfs
Big Creek
20.7
191.1
418.6
1394.9
3630.7
6
194.6
424.0
1409.9
3662.8
0.5
375.6
790.6
2512.0
6270.0
Tributary #1
2.1
5.0
1 15.9
64.8
161.0
Tributary #2
5.1
246.5
491.8
1421.1
3285.1
Table 13 identifies the field measured existing stream channel Manning's values and
the proposed stream restoration design values.
8 BayLand Consultants & Designers, Inc.
Appendix B-11

Big Creek IV Stream Restoration
Hydrologic and Hydraulic Study August 2016
4.1, HYDRAULIC ANALYSIS REPORT
Tables 14 through 17 detail the results of the hydraulic comparison between existing
and proposed conditions for the 1-, 2-, 10- and 100 -year storm events for Big Creek IV
and its two tributaries. The results highlight the changes in the water surface elevation,
channel velocity and channel shear stresses. The full hydraulic model can be found in
Appendix D.
9 BayLand Consultants & Designers, Inc.
Appendix B-12

Big Creek IV Stream Restoration
Hydrologic and Hydraulic Study August 2016
10 BayLand Consultants & Designers, Inc.
Appendix B-13
Table.
• Creek IV
& Tributariesand
River
Station
EX. W.S.
Elevation
PR. W.S.
Elevation
Change
Elevation
EX.
Velocity
PR.
Velocity
Change
Velocity
EX.
Channel
Shear
Stress
PR.
Channel
Shear
Stress
Change
Channel
Shear
Stress
ft
ft
ft)
(ft/s)
(ft/s)
(Ib/sq ft(lb/sq
ft
Big Creek
20.5 1069.91 1069.56
-0.35 3.17 3.74 17.98 0.35 0.51
45.71
20 1069.26 1068.66
-0.60 3.79 4.70 24.01 0.58 0.85
46.55
19 1068.85 1068.58
-0.27 3.56 2.19 -38.48 0.48 0.16
-66.67
18 1068.81 1068.52
-0.29 1.90 1.91 0.53 0.11 0.11
0.00
17 1068.75 1068.08
-0.67 2.08 4.63 122.60 0.14 0.83
492.86
16 1068.69 1067.90
-0.79 1.42 2.05 44.37 0.07 0.14
100.00
15 1068.38 1067.27
-1.11 2.57 4.81 87.16 0.24 0.90
275.00
14 1068.21 1066.90
-1.31 2.40 2.38 -0.83 0.20 0.18
-10.00
13 1066.92 1065.85
-1.07 3.21 4.32 34.58 0.36 0.71
97.22
12 1066.64 1065.68
-0.96 2.60 2.28 -12.31 0.24 0.17
-29.17
11 1066.19 1065.45
-0.74 2.97 2.09 -29.63 0.31 0.14
-54.84
10 1065.92 1064.91
-1.01 3.00 3.96 32.00 0.30 0.58
93.33
9 1065.16 1064.49
-0.67 3.89 2.15 -44.73 0.55 0.15
-72.73
8 1064.81 1063.98
-0.83 2.32 3.93 69.40 0.19 0.57
200.00
7 1064.44 1063.58
-0.86 2.19 3.73 70.32 0.17 0.51
200.00
6 1064.05 1063.07
-0.98 3.79 3.85 1.58 0.51 0.54
5.88
5 1063.67 1061.82
-1.85 1.80 3.43 90.56 0.11 0.41
272.73
4 1063.41 1061.75
-1.66 3.18 2.37 -25.47 0.36 0.18
-50.00
3 1063.16 1061.45
-1.71 2.97 4.00 34.68 0.33 0.59
78.79
2 1062.29 1061.16
-1.13 2.05 2.32 13.17 0.14 0.18
28.57
1 1061.83 1060.96
-0.87 2.92 2.13 -27.05 0.29 0.14
-51.72
0.5 1060.16 1060.19
0.03 5.77 5.70 -1.21 1.18 1.14
-3.39
Tributary #1
2
1065.11
1065.04
-0.07
1.19
2.34
96.64
0.07
0.32
357.14
1
1065.06
1064.20
-0.86
0.60
2.47
311.67
0.02
0.37
1750.00
Tributary #2
5
1063.48
1062.32
-1.16
1.00
6.82
582.00 0.04 1.77
4325.00
4
1063.42
1061.71
-1.71
1.43
3.71
159.44 0.07 0.44
528.57
3
1062.53
1061.35
-1.18
6.31
3.59
-43.11 1.48 0.44
-70.27
2
1062.19
1061.09
-1.10
2.79
2.90
3.94 0.30 0.28
-6.67
1
1061.45
1061.00
-0.45
5.64
2.63
-53.37 1.11 0.20
-81.98
10 BayLand Consultants & Designers, Inc.
Appendix B-13

Big Creek IV Stream Restoration
Hydrologic and Hydraulic Study August 2016
11 BayLand Consultants & Designers, Inc.
Appendix B-14
Table 15 - 2 -YR Hydraulic Analysis
Big
Creek IV
& Tributaries #1 and #2
River
Station
EX. W.S.
Elevation
PR. W.S.
Elevation
Change
Elevation
EX.
Velocity
PR.
Velocity
Change
Velocity
EX.
Channel
Shear
Stress
PR.
Channel
Shear
Stress
Change
Channel
Shear
Stress
ft
ft
ft)
(ft/s)
(ft/s)
(Ib/s ft(lb/sq
ft
Big Creek
20.5 1071.18 1070.93 -0.25 4.26 4.29 0.70 0.54 0.82
51.85
20 1070.64 1070.09 -0.55 4.03 5.32 32.01 0.55 0.93
69.09
19 1070.40 1070.08 -0.32 3.81 3.19 -16.27 0.48 0.31
-35.42
18 1070.34 1069.98 -0.36 2.85 2.98 4.56 0.23 0.25
8.70
17 1070.27 1069.50 -0.77 2.73 5.27 93.04 0.23 0.92
300.00
16 1070.24 1069.41 -0.83 1.78 3.03 70.22 0.10 0.27
170.00
15 1069.96 1068.86 -1.10 3.16 5.09 61.08 0.33 0.84
154.55
14 1069.80 1068.48 -1.32 3.04 3.42 12.50 0.29 0.33
13.79
13 1068.39 1067.48 -0.91 4.28 4.73 10.51 0.59 0.71
20.34
12 1068.18 1067.40 -0.78 3.07 3.16 2.93 0.31 0.30
-3.23
11 1067.73 1067.09 -0.64 3.45 3.03 -12.17 0.40 0.27
-32.50
10 1067.43 1066.55 -0.88 3.98 4.42 11.06 0.52 0.61
17.31
9 1066.36 1065.99 -0.37 5.20 3.23 -37.88 0.89 0.31
-65.17
8 1066.20 1065.27 -0.93 3.17 4.99 57.41 0.31 0.81
161.29
7 1065.88 1064.88 -1.00 2.84 4.80 69.01 0.25 0.74
196.00
6 1065.39 1064.39 -1.00 4.78 4.88 2.09 0.76 0.76
0.00
5 1064.97 1063.53 -1.44 2.47 4.12 66.80 0.18 0.53
194.44
4 1064.61 1063.44 -1.17 4.24 3.29 -22.41 0.62 0.32
-48.39
3 1064.52 1063.20 -1.32 3.02 4.29 42.05 0.31 0.57
83.87
2 1064.02 1062.92 -1.10 2.61 3.17 21.46 0.20 0.30
50.00
1 1063.64 1062.66 -0.98 3.52 3.06 -13.07 0.40 0.27
-32.50
0.5 1061.47 1061.50 0.03 7.53 7.44 -1.20 1.77 1.72
-2.82
Tributary #1
2
1066.57
1065.78
-0.79
0.93
2.29
146.24
0.04 0.26
550.00
1
1066.55
1065.62
-0.93
0.70
1.24
77.14
0.02 0.07
250.00
Tributary #2
5
1065.07
1063.53
-1.54
1.05
7.79
641.90 0.04 1.95 4775.00
4
1064.99
1063.28
-1.71
1.86
4.72
153.76 0.11 0.63 472.73
3
1064.06
1063.00
-1.06
6.73
4.32
-35.81 1.46 0.57 -60.96
2
1063.84
1062.79
-1.05
3.57
3.67
2.80 0.47 0.39 -17.02
1
1062.95
1062.69
-0.26--76.61
3.58
-45.84 1.39 0.34 -75.54
11 BayLand Consultants & Designers, Inc.
Appendix B-14

Big Creek IV Stream Restoration
Hydrologic and Hydraulic Study August 2016
12 BayLand Consultants & Designers, Inc.
Appendix B-15
Table
River
Station
EX. W.S.
Elevation
PR. W.S.
Elevation
Change
Elevation
EX.
Velocity
PR.
Velocity
Change
Velocity
EX.
Channel
Shear
Stress
PR.
Channel
Shear
Stress
Change
Channel
Shear
Stress
ft)
(ft1s)
(%
(lb/s ft
(lb/s ft
Big Creek
20.5 1073.38 1073.28 -0.10 4.62 3.86 -16.45 0.54 0.64 18.52
20 1073.21 1072.92 -0.29 3.50 5.09 45.43 0.31 0.68 119.35
19 1072.83 1072.91 0.08 3.73 3.84 2.95 0.39 0.38 -2.56
18 1072.66 1072.24 -0.42 4.18 6.64 58.85 0.45 1.10 144.44
17 1072.41 1072.49 0.08 3.56 4.18 17.42 0.35 0.45 28.57
16 1072.36 1072.40 0.04 2.78 3.65 31.29 0.20 0.34 70.00
15 1071.74 1071.58 -0.16 5.73 7.56 31.94 1.02 1.49 46.08
14 1071.54 1071.19 -0.35 4.74 5.66 19.41 0.62 0.79 27.42
13 1070.58 1070.32 -0.26 5.05 5.82 15.25 0.71 0.87 22.54
12 1070.38 1070.28 -0.10 4.05 4.43 9.38 0.51 0.50 -1.96
11 1069.87 1069.81 -0.06 4.96 4.97 0.20 0.69 0.63 -8.70
10 1069.59 1069.49 -0.10 5.28 5.07 -3.98 0.83 0.65 -21.69
9 1069.41 1069.02 -0.39 4.12 4.49 8.98 0.49 0.50 2.04
8 1068.53 1068.62 0.09 4.69 5.11 8.96 0.59 0.65 10.17
7 1068.27 1068.21 -0.06 3.98 5.32 33.67 0.49 0.71 44.90
6 1067.91 1067.09 -0.82 5.30 8.28 56.23 0.83 1.77 113.25
5 1067.61 1067.25 -0.36 2.94 3.13 6.46 0.24 0.27 12.50
4 1067.47 1067.15 -0.32 3.48 3.70 6.32 0.41 0.33 -19.51
3 1067.45 1067.15 -0.30 2.98 3.30 10.74 0.26 0.26 0.00
2 1067.10 1066.79 -0.31 3.84 4.38 14.06 0.37 0.47 27.03
1 1067.02 1066.64 -0.38 3.02 3.68 21.85 0.24 0.31 29.17
0.5 1065.86 1065.45 -0.41 7.47 8.70 16.47 1.40 1.92 37.14
Tributary #1
2
1068.68
1068.80
0.12
1.12
1.10 -1.79
0.05
0.04
-20.00
1
1068.68
1068.80
0.12
0.75
0.61 -18.67
0.02
0.01
-50.00
Tributary #2
5 1067.12 1067.08 -0.04 1.64 4.54 176.83 0.09 0.51 466.67
4 1066.91 1066.66 -0.25 3.33 5.57 67.27 0.35 0.73 108.57
3 1066.91 1066.78 -0.13 2.50 2.67 6.80 0.19 0.17 -10.53
2 1066.86 1066.75 -0.11 1.96 2.35 19.90 0.13 0.13 0.00
1 1066.79 1066.70 -0.09 2.64 2.90 9.85 0.18 0.19 5.56
12 BayLand Consultants & Designers, Inc.
Appendix B-15

Big Creek IV Stream Restoration
Hydrologic and Hydraulic Study August 2016
13 BayLand Consultants & Designers, Inc.
Appendix B-16
Table00
River
Station
EX. W.S.
Elevation
PR. W.S.
Elevation
Change
Elevation
EX.
Velocity
PR.
Velocity
Change
Velocity
EX.
Channel
Shear
Stress
PR.
Channel
Shear
Stress
Change
Channel
Shear
Stress
ft
ft
ft)
(ft/s)
(ft1s)
(%
(lb/s ft
(lb/s ft
Big Creek
20.5 1074.54 1074.64 0.10 7.02 5.26 -25.07 1.18 1.08 -8.47
20 1074.24 1074.23 -0.01 5.42 6.79 25.28 0.75 1.12 49.33
19 1074.12 1074.17 0.05 5.22 5.63 7.85 0.70 0.77 10.00
18 1073.89 1073.96 0.07 5.98 6.18 3.34 0.88 0.89 1.14
17 1073.82 1073.92 0.10 4.67 5.17 10.71 0.55 0.64 16.36
16 1073.70 1073.77 0.07 4.28 5.08 18.69 0.45 0.61 35.56
15 1073.29 1073.52 0.23 6.19 6.59 6.46 1.08 1.02 -5.56
14 1073.03 1073.02 -0.01 5.87 6.56 11.75 0.87 0.99 13.79
13 1072.26 1072.35 0.09 5.69 5.94 4.39 0.82 0.82 0.00
12 1071.96 1072.21 0.25 5.45 5.52 1.28 0.84 0.71 -15.48
11 1071.18 1071.58 0.40 7.49 6.78 -9.48 1.43 1.09 -23.78
10 1070.79 1071.19 0.40 7.64 6.58 -13.87 1.61 1.00 -37.89
9 1070.23 1070.48 0.25 7.25 6.45 -11.03 1.45 0.98 -32.41
8 1070.10 1069.85 -0.25 5.72 7.12 24.48 0.81 1.20 48.15
7 1069.99 1069.79 -0.20 4.39 5.89 34.17 0.54 0.80 48.15
6 1069.88 1069.67 -0.21 4.23 5.23 23.64 0.47 0.62 31.91
5 1069.66 1069.51 -0.15 3.44 3.42 -0.58 0.30 0.28 -6.67
4 1069.55 1069.40 -0.15 3.71 4.49 21.02 0.43 0.44 2.33
3 1069.54 1069.41 -0.13 3.47 4.03 16.14 0.32 0.35 9.37
2 1069.28 1069.08 -0.20 4.48 4.82 7.59 0.45 0.52 15.56
1 1069.23 1068.90 -0.33 3.29 4.16 26.44 0.26 0.37 42.31
0.5 1067.76 1067.22 -0.54 10.18 11.93 17.19 2.39 3.33 39.33
Tributary #1
2
1070.20
1070.05
-0.15
1.09
1.30
19.27
0.04
0.05
25.00
1
1070.20
1070.05
-0.15
0.67
0.68
1.49
0.01
0.01
0.00
Tributary #2
5 1069.11 1069.05 -0.06 2.03 4.23 108.37 0.13 0.40 207.69
4 1069.04 1068.97 -0.07 2.70 3.93 45.56 0.21 0.33 57.14
3 1069.02 1068.96 -0.06 2.32 2.49 7.33 0.14 0.14 0.00
2 1069.00 1068.94 -0.06 1.67 2.01 20.36 0.08 0.09 12.50
1 1068.98 1068.92 -0.06 2.11 2.55 20.85 0.11 0.14 27.27
13 BayLand Consultants & Designers, Inc.
Appendix B-16

Big Creek IV Stream Restoration
Hydrologic and Hydraulic Study August 2016
4.2. HYDRAULIC RESULTS
The hydraulic analysis indicates that the proposed stream restoration project will reduce
the water surface elevation, channel velocities and channel shear stress at several
cross sections, while several cross sections show increases in water surface elevation,
channel velocities and channel shear stresses. These increases are attributed to the
geomorphological changes of the spacing stream features (pools and riffles, etc...)
along with stream meander geometry changes from the existing to the proposed
conditions and do not reflect any adverse changes to the proposed reach. The
proposed channel velocities and shear stresses are non-erosive for the proposed
stream restoration bed material and channel stability. The stream restoration project will
focus on the addition of riverine structures and grade controls to prevent future
degradation and provide habitat for aquatic species. Implementation of a vigorous,
native landscaping and limitation of access by adjacent agricultural use will greatly
improve the ascetics and prevent any future degradation of this reach. Flooding risks to
landowners are not increased by the stream restoration project. The locations of the
hydraulic cross sections can be found within Appendix F and a map of the existing and
proposed 100 -year water surface elevations is provided in Appendix G.
14 BayLand Consultants & Designers, Inc.
Appendix B-17

Big Creek IV Stream Restoration
Hydrologic and Hydraulic Study August 2016
5. REFERENCES
Carpenter, D.H., 1980, Technique for estimating magnitude and frequency of floods in
Maryland: U.S. Geological Survey Water -Resources Investigations Open -File Report
80-1016.
Dillow, J.J.A., 1996, Technique for estimating magnitude and frequency of peak flows in
Maryland: U.S. Geological Survey Water -Resources Investigations Report 95-4154.
Moglen, G., Thomas, W., Miller, A.C, 2002. Evaluation of alternative statistical methods
for estimating frequency of peak flows in Maryland, Report SP907C48: Maryland
Department of Transportation, State Highway Administration.
U.S. Department of Agriculture, 1985, National Hydrologic Handbook, Section 4,
Hydrology: Soil Conservation Service, Washington, DC.
U.S. Department of Agriculture, 1986, Urban hydrology for small watersheds: Soil
Conservation Service, Technical Release 55, Washington, DC.
U.S. Department of Agriculture, 1992. Computer program for project formulation -
hydrology. SCS Technical Release 20, Washington,DC.
U.S. Department of Agriculture, 2013. Web Soil Survey
http://websoilsurvey.nres.usda.gov/app/HomePage.htm, accessed August 2016.
Weaver, J.C., Feaster, T.D., and Gotvald, A.J, 2009. Magnitude and Frequency of Rural
Floods in the Southeastern United States, through 2006: Volume 2, North Carolina,
Report 2009-5158: US Department of the Interior, US Geological Survey.
15 BayLand Consultants & Designers, Inc.
Appendix B-18

APPENDIX A
NRCS Soils/Land Use
Appendix B-19

" WfB2 f"
WfC2 }'. y . �`.•
Woo
WoDW,fB2��W12�.
W^fC�2SjE
' WfC2
Or ! �fB2 WfB2 ,P�j'1WoD IV[sD
WD�W,opWoE�g�C �WfC2 e
WfB2
WfR-2 WoD fC2 1M.. Y �
W�fB2� �WfB2� , �li' � �
��� WfB2 WfC2 'W,fC2 WoD%StE ' �°•J' � '� ,, � '
WfC2�s� TcC W WoD ~%�W�+� �,W.oD RbD -,°� •�. _ �-
WfC2�
- .�� W,oD WfC2 StE WfG2WoD�RbD TtC ; ,,,=.�
lWf�C2 �.� - �BaC•; .�.r rr
WfC2 WfB2 �W6E �Il WTtGITW TtC ToB'
-2 `
WoD �� WfC'-2
NIB -2 TWoD'►�TtC TtC�R�D�
WfB2 .. �r -� �� RbrD W/ TtC ToBToB
BbC WoD�WoD
f Wf,C2 �'„i WfB2 �,►yMtiTitC RbD ��► TtCNFeC2'
::n •5 Vi
``BaC WWI �RbD TtCT4B ToB �R_FEFPC.2
Wf.C2�WfC' BaC� . , Fe'_B2 TtCa �1►BbD��I� FpC~2
WfC2��6 C TjtC TitC Cs"+p� FeC�2 FeD2 ppB2FpC�2
WoD ,4..-�? W�f,C2 L -TitC .ti �►r �.� w+. i11'.
pir
P-., BbC k RrE� ,D�g DFB FeD2 Rr,E� FpD2 D�,C�2
fBrEbDiWoE�
BbBWfC2 TtWoERRsD FeD2 � BbC, aA FpD2
RFE��WfG2 ��►.E D21 Bb,C
RbD -
FsE F D2
�C•-2 `FC�2' r Rr FeC2 RpE FpD2.
WoD,WfC2 �- ►- N
I
WfB2 '� ���qi yyoD FeD2tTtCF�E 1�'� �p
' � ,• ����FeB2�sE���ERpE`r\ • R
/ 2iFpB2 CeB2Fp�D2 " . ;

Hydrologic Soil Group—Stokes County, North Carolina, and Surry County, North Carolina
(BIG CREEK WEST DA)
MAP LEGEND
Area of Interest (AOI)
Area of Interest (AOI)
Soils
Soil Rating Polygons
0 A
0 A/D
0 B
0 B/D
0 C
0 C/D
0 D
0 Not rated or not available
Soil Rating Lines
pff0 A
A/D
B
rwr B/D
C
rwr C/D
ry D
r / Not rated or not available
Soil Rating Points
0 A
E3 A/D
■ B
■ B/D
MAP INFORMATION
p C
The soil surveys that comprise your AOI were mapped at 1:24,000.
p C/D
Please rely on the bar scale on each map sheet for map
measurements.
® D
p Not rated or not available
Source of Map: Natural Resources Conservation Service
Web Soil Survey URL: http://websoilsurvey.nres.usda.gov
Water Features
Coordinate System: Web Mercator (EPSG:3857)
Streams and Canals
Maps from the Web Soil Survey are based on the Web Mercator
Transportation
projection, which preserves direction and shape but distorts
t++ Rails
distance and area. A projection that preserves area, such as the
Albers equal-area conic projection, should be used if more accurate
n-rr Interstate Highways
calculations of distance or area are required.
US Routes
This product is generated from the USDA-NRCS certified data as of
Major Roads
the version date(s) listed below.
Local Roads
Soil Survey Area: Stokes County, North Carolina
Survey Area Data: Version 15, Sep 16, 2015
Background
Aerial Photography
Soil Survey Area: Surry County, North Carolina
Survey Area Data: Version 19, Sep 16, 2015
Your area of interest (AOI) includes more than one soil survey area.
These survey areas may have been mapped at different scales, with
a different land use in mind, at different times, or at different levels
of detail. This may result in map unit symbols, soil properties, and
interpretations that do not completely agree across soil survey area
boundaries.
Soil map units are labeled (as space allows) for map scales 1:50,000
or larger.
Date(s) aerial images were photographed: Oct 22, 2010—Apr 30,
2011
The orthophoto or other base map on which the soil lines were
compiled and digitized probably differs from the background
imagery displayed on these maps. As a result, some minor shifting
of map unit boundaries may be evident.
USDA Natural Resources A"-eMiJ $94M 8/12/2016
Iiiiiii Conservation Service National Cooperative Soil Survey Page 2 of 6

Hydrologic Soil Group—Stokes County, North Carolina, and Surry County, North Carolina
Hydrologic Soil Group
BIG CREEK WEST DA
Hydrologic Soil Group— Summary by Map Unit — Stokes County, North Carolina (NC169)
Map unit symbol
Map unit name
Rating
Acres in AOI
Percent of AOI
CcB
Clifford fine sandy loam,
B
0.8
0.0%
2 to 8 percent slopes
CeB2
Clifford sandy clay loam,
B
1.1
0.0%
2 to 8 percent slopes,
moderately eroded
Dan River and Comus
C
39.1
0.9%
DaA
soils, 0 to 4 percent
slopes, occasionally
flooded
DpB2
Danripple sandy clay
B
15.5
0.4%
loam, 2 to 8 percent
slopes, moderately
eroded
DpC2
Danripple sandy clay
B
14.3
0.3%
loam, 8 to 15 percent
slopes, moderately
eroded
FpB2
Fairview -Poplar Forest
B
4.2
0.1%
complex, 2 to 8
percent slopes,
moderately eroded
FpC2
Fairview -Poplar Forest
B
127.2
2.9%
complex, 8 to 15
percent slopes,
moderately eroded
FpD2
Fairview -Poplar Forest
B
46.1
1.1%
complex, 15 to 25
percent slopes,
moderately eroded
RpE
Rhodhiss, Fairview, and
B
92.4
2.1%
Stott Knob soils, 25 to
60 percent slopes
0.3%
ToC
Toast loam, 8 to 15
B
12.0
percent slopes
W
Water
1.3
0.0%
Subtotals for Soil Survey Area
354.0
8.2%
Totals for Area of Interest
4,312.7
100.0%
Hydrologic Soil Group— Summary by Map Unit — Surry County, North Carolina (NC171)
Map unit symbol
Map unit name
Rating
Acres in AOI
Percent of AOI
BaC
Bandana-Tate-Nikwasi
A/D
33.2
0.8%
complex, 0 to 15
percent slopes,
frequently flooded
USDA Natural Resources
r Conservation Service
Web Soil Survey
National Cooperative Soil Survey
Appendix B-22
8/12/2016
Page 3 of 6

Hydrologic Soil Group—Stokes County, North Carolina, and Surry County, North Carolina
BIG CREEK WEST DA
Hydrologic Soil Group— Summary by Map Unit — Surry County, North Carolina (NC171)
Map unit symbol
Map unit name
Rating
Acres in AOI
Percent of AOI
BbB
Braddock fine sandy
B
2.0
0.0%
loam, 2 to 8 percent
slopes
BbC
Braddock fine sandy
B
41.7
1.0%
loam, 8 to 15 percent
slopes
BbD
Braddock fine sandy
B
7.1
0.2%
loam, 15 to 25 percent
slopes
CsA
Colvard and Suches
A
159.0
3.7%
soils, 0 to 3 percent
slopes, occasionally
flooded
DrB
Dillard fine sandy loam, 2
C
6.7
0.2%
to 8 percent slopes,
rarely flooded
FeB2
Fairview sandy clay
B
24.2
0.6%
loam, 2 to 8 percent
slopes, moderately
eroded
FeC2
Fairview sandy clay
C
62.9
1.5%
loam, 8 to 15 percent
slopes, moderately
eroded
FeD2
Fairview sandy clay
C
57.2
1.3%
loam, 15 to 25 percent
slopes, moderately
eroded
FsE
Fairview -Stott Knob
B
84.3
2.0%
complex, 25 to 45
percent slopes
MsD
Meadowfield-Stott Knob
C
19.1
0.4%
complex, 15 to 25
percent slopes, very
stony
RbD
Rhodhiss-Bannertown
B
366.7
8.5%
complex, 15 to 25
percent slopes, very
rocky
RrE
Rhodhiss-Bannertown-
B
311.9
7.2%
Rock outcrop complex,
25 to 60 percent
slopes, very bouldery
RsD
Rhodhiss-Stott Knob
B
38.7
0.9%
complex, 15 to 25
percent slopes, stony
StE
Stott Knob gravelly loam,
C
253.6
5.9%
25 to 45 percent
slopes, stony
TcC
Tate-Colvard complex, 0
B
43.1
1.0%
to 15 percent slopes,
frequently flooded
usr),x Natural Resources
� Conservation Service
Web Soil Survey
National Cooperative Soil Survey
Appendix B-23
8/12/2016
Page 4 of 6

Hydrologic Soil Group—Stokes County, North Carolina, and Surry County, North Carolina
BIG CREEK WEST DA
Hydrologic Soil Group— Summary by Map Unit — Surry County, North Carolina (NC171)
Map unit symbol
Map unit name
Rating
Acres in AOI
Percent of AOI
ToB
Toast coarse sandy
B
45.8
1.1%
loam, 2 to 8 percent
slopes, rocky
TtC
Toast-Bannertown
B
328.7
7.6%
complex, 8 to 15
percent slopes, very
rocky
W
Water
5.5
0.1%
Wf132
Woolwine-Fairview-
B
207.9
4.8%
Westfield complex, 2
to 8 percent slopes,
moderately eroded
WfC2
Woolwine-Fairview-
C
816.4
18.9%
Westfield complex, 8
to 15 percent slopes,
moderately eroded
WoD
Woolwine-Fairview-
C
628.0
14.6%
Westfield complex, 15
to 25 percent slopes,
stony
WoE
Woolwine-Fairview-
C
415.3
9.6%
Westfield complex, 25
to 45 percent slopes,
stony
Subtotals for Soil Survey Area
3,958.8
91.8%
Totals for Area of Interest
4,312.7
100.0%
USDA Natural Resources
r Conservation Service
Web Soil Survey
National Cooperative Soil Survey
Appendix B-24
8/12/2016
Page 5 of 6

Hydrologic Soil Group—Stokes County, North Carolina, and Surry County, North Carolina
Description
Hydrologic soil groups are based on estimates of runoff potential. Soils are
assigned to one of four groups according to the rate of water infiltration when the
soils are not protected by vegetation, are thoroughly wet, and receive precipitation
from long -duration storms.
The soils in the United States are assigned to four groups (A, B, C, and D) and
three dual classes (A/D, B/D, and C/D). The groups are defined as follows:
Group A. Soils having a high infiltration rate (low runoff potential) when thoroughly
wet. These consist mainly of deep, well drained to excessively drained sands or
gravelly sands. These soils have a high rate of water transmission.
Group B. Soils having a moderate infiltration rate when thoroughly wet. These
consist chiefly of moderately deep or deep, moderately well drained or well drained
soils that have moderately fine texture to moderately coarse texture. These soils
have a moderate rate of water transmission.
Group C. Soils having a slow infiltration rate when thoroughly wet. These consist
chiefly of soils having a layer that impedes the downward movement of water or
soils of moderately fine texture or fine texture. These soils have a slow rate of water
transmission.
Group D. Soils having a very slow infiltration rate (high runoff potential) when
thoroughly wet. These consist chiefly of clays that have a high shrink -swell
potential, soils that have a high water table, soils that have a claypan or clay layer
at or near the surface, and soils that are shallow over nearly impervious material.
These soils have a very slow rate of water transmission.
If a soil is assigned to a dual hydrologic group (A/D, B/D, or C/D), the first letter is
for drained areas and the second is for undrained areas. Only the soils that in their
natural condition are in group D are assigned to dual classes.
Rating Options
Aggregation Method: Dominant Condition
Component Percent Cutoff: None Specified
Tie-break Rule: Higher
USDA Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
Appendix B-25
BIG CREEK WEST DA
8/12/2016
Page 6 of 6

N
W
545600
360 32'347'N
546300
Z4
ate'
S
N
360 30' 2" N
545600 546300
3
ro
N Map Scale: 1:9,690 if printed on D landscape (34" x 22") sheet.
Meters
N 0 100 200 400 600
Feet
0 450 900 1800 2700
Map projection: Web Mercator Comer coordinates: WGS84 Edge tics: UTM Zone 17N WGS84
USDA Natural Resources
Conservation Service
547000
illMStE
547000
547700
StD
548400
eL _
Estes
TtC
,• RbD .
547700 548400
I�
Hydrologic Soil Group—Stokes County, North Carolina, and Surry County, North Carolina
(DA2)
549100 549800
WoD
TtC
BbC
� ToB
TtC
I
- I
549100
Aw
4
V� 7��5'M► S�E
wfc�2 r
WoD SSD
TlTl O
RrE
U(. D
550500
551200
551900
552600
TtC
TtC
ToC
FpC�-2
1 c .
{
� � ;. y
'x'10 I( F irr 1.. ""± "�� '! � - � I "(P .. -- :�Y • -
Aj
.y�
,1 {t tom°' t r
r 1
o D
:
o �
b�.�'�#� �<:'� �. 'i �^��M � `.r '+�F ���; D o `� R. `„' a :.� ... - r: , _.• �M.
< n wf
4c - 7'� ir�� y}t-fes' '.l '•i? `+. w �� - _ y gf �, f •,�
w
z'1 _
. - ,� - ... - - .,, a. • m'� fill
A"-'&Mif 6416
National Cooperative Soil Survey
v
o
W
5531300
i 360 32'34'N
T 360 30'2" N
553300
3
N
m
8/3/2016
Page 1 of 6

Hydrologic Soil Group—Stokes County, North Carolina, and Surry County, North Carolina
(DA2)
MAP LEGEND
Area of Interest (AOI)
Area of Interest (AOI)
Soils
Soil Rating Polygons
0 A
0 A/D
0 B
0 B/D
0 C
0 C/D
0 D
0 Not rated or not available
Soil Rating Lines
pff0 A
Soil Rating Points
0 A
E3 A/D
■ B
■ B/D
o C
0 C/D
E3 D
0 Not rated or not available
Water Features
Streams and Canals
Transportation
t++ Rails
Interstate Highways
US Routes
Major Roads
Local Roads
Background
W Aerial Photography
MAP INFORMATION
The soil surveys that comprise your AOI were mapped at 1:24,000
Warning: Soil Map may not be valid at this scale.
Enlargement of maps beyond the scale of mapping can cause
misunderstanding of the detail of mapping and accuracy of soil line
placement. The maps do not show the small areas of contrasting
soils that could have been shown at a more detailed scale.
Please rely on the bar scale on each map sheet for map
measurements.
Source of Map: Natural Resources Conservation Service
Web Soil Survey URL: http://websoilsurvey.nres.usda.gov
Coordinate System: Web Mercator (EPSG:3857)
Maps from the Web Soil Survey are based on the Web Mercator
projection, which preserves direction and shape but distorts
distance and area. A projection that preserves area, such as the
Albers equal-area conic projection, should be used if more accurate
calculations of distance or area are required.
This product is generated from the USDA-NRCS certified data as of
the version date(s) listed below.
Soil Survey Area: Stokes County, North Carolina
Survey Area Data: Version 15, Sep 16, 2015
Soil Survey Area: Surry County, North Carolina
Survey Area Data: Version 19, Sep 16, 2015
Your area of interest (AOI) includes more than one soil survey area.
These survey areas may have been mapped at different scales, with
a different land use in mind, at different times, or at different levels
of detail. This may result in map unit symbols, soil properties, and
interpretations that do not completely agree across soil survey area
boundaries.
Soil map units are labeled (as space allows) for map scales 1:50,000
or larger.
Date(s) aerial images were photographed: Oct 22, 2010—Apr 30,
2011
The orthophoto or other base map on which the soil lines were
compiled and digitized probably differs from the background
imagery displayed on these maps. As a result, some minor shifting
of map unit boundaries may be evident.
USDA Natural Resources A"*40�&V 8/3/2016
Iiiiiii Conservation Service National Cooperative Soil Survey Page 2 of 6
A/D
B
rwr
B/D
C
rwr
C/D
ry
D
r e
Not rated or not available
Soil Rating Points
0 A
E3 A/D
■ B
■ B/D
o C
0 C/D
E3 D
0 Not rated or not available
Water Features
Streams and Canals
Transportation
t++ Rails
Interstate Highways
US Routes
Major Roads
Local Roads
Background
W Aerial Photography
MAP INFORMATION
The soil surveys that comprise your AOI were mapped at 1:24,000
Warning: Soil Map may not be valid at this scale.
Enlargement of maps beyond the scale of mapping can cause
misunderstanding of the detail of mapping and accuracy of soil line
placement. The maps do not show the small areas of contrasting
soils that could have been shown at a more detailed scale.
Please rely on the bar scale on each map sheet for map
measurements.
Source of Map: Natural Resources Conservation Service
Web Soil Survey URL: http://websoilsurvey.nres.usda.gov
Coordinate System: Web Mercator (EPSG:3857)
Maps from the Web Soil Survey are based on the Web Mercator
projection, which preserves direction and shape but distorts
distance and area. A projection that preserves area, such as the
Albers equal-area conic projection, should be used if more accurate
calculations of distance or area are required.
This product is generated from the USDA-NRCS certified data as of
the version date(s) listed below.
Soil Survey Area: Stokes County, North Carolina
Survey Area Data: Version 15, Sep 16, 2015
Soil Survey Area: Surry County, North Carolina
Survey Area Data: Version 19, Sep 16, 2015
Your area of interest (AOI) includes more than one soil survey area.
These survey areas may have been mapped at different scales, with
a different land use in mind, at different times, or at different levels
of detail. This may result in map unit symbols, soil properties, and
interpretations that do not completely agree across soil survey area
boundaries.
Soil map units are labeled (as space allows) for map scales 1:50,000
or larger.
Date(s) aerial images were photographed: Oct 22, 2010—Apr 30,
2011
The orthophoto or other base map on which the soil lines were
compiled and digitized probably differs from the background
imagery displayed on these maps. As a result, some minor shifting
of map unit boundaries may be evident.
USDA Natural Resources A"*40�&V 8/3/2016
Iiiiiii Conservation Service National Cooperative Soil Survey Page 2 of 6

Hydrologic Soil Group—Stokes County, North Carolina, and Surry County, North Carolina
Hydrologic Soil Group
Hydrologic Soil Group— Summary by Map Unit — Stokes County, North Carolina (NC169)
Map unit symbol
Map unit name
Rating
Acres in AOI
Percent of AOI
BaB
Banister fine sandy loam,
C
17.1
0.7%
2 to 8 percent slopes,
rarely flooded
BeA
Belews Lake loam, 0 to 3
C/D
0.0
0.0%
percent slopes, rarely
flooded
DaA
Dan River and Comus
C
104.5
4.3%
soils, 0 to 4 percent
slopes, occasionally
flooded
DpB2
Danripple sandy clay
B
2.2
0.1%
loam, 2 to 8 percent
slopes, moderately
eroded
DpC2
Danripple sandy clay
B
8.8
0.4%
loam, 8 to 15 percent
slopes, moderately
eroded
FgC
Fairview gravelly fine
B
0.0
0.0%
sandy loam, 8 to 15
percent slopes
FpB2
Fairview -Poplar Forest
B
27.6
1.1%
complex, 2 to 8
percent slopes,
moderately eroded
FpC2
Fairview -Poplar Forest
B
346.9
14.3%
complex, 8 to 15
percent slopes,
moderately eroded
FpD2
Fairview -Poplar Forest
B
256.4
10.6%
complex, 15 to 25
percent slopes,
moderately eroded
RnC
Rhodhiss fine sandy
B
5.6
0.2%
loam, 8 to 15 percent
slopes
RnD
Rhodhiss fine sandy
B
19.0
0.8%
loam, 15 to 25 percent
slopes
RpE
Rhodhiss, Fairview, and
B
175.1
7.2%
Stott Knob soils, 25 to
60 percent slopes
SO
Stott Knob gravelly loam,
C
41.4
1.7%
8 to 25 percent slopes,
stony
USDA Natural Resources
r Conservation Service
Web Soil Survey
National Cooperative Soil Survey
Appendix B-28
DA2
8/3/2016
Page 3 of 6

Hydrologic Soil Group—Stokes County, North Carolina, and Surry County, North Carolina
Hydrologic Soil Group— Summary by Map Unit — Stokes County, North Carolina (NC169)
Map unit symbol
Map unit name
Rating
Acres in AOI
Percent of AOI
StE
Stott Knob gravelly loam,
C
62.5
2.6%
25 to 60 percent
slopes, stony
ToC
Toast loam, 8 to 15
B
78.6
3.2%
percent slopes
ToD
Toast loam, 15 to 25
B
40.3
1.7%
CsA
percent slopes
A
78.9
3.2%
W
Water
1.9
0.1%
Subtotals for Soil Survey Area
1,187.9
48.9%
Totals for Area of Interest
2,428.8
100.0%
Hydrologic Soil Group— Summary by Map Unit — Surry County, North Carolina (NC171)
Map unit symbol
Map unit name
Rating
Acres in AOI
Percent of AOI
BbB
Braddock fine sandy
B
8.8
0.4%
loam, 2 to 8 percent
slopes
BbC
Braddock fine sandy
B
5.8
0.2%
loam, 8 to 15 percent
slopes
CsA
Colvard and Suches
A
78.9
3.2%
soils, 0 to 3 percent
slopes, occasionally
flooded
FeC2
Fairview sandy clay
C
11.7
0.5%
loam, 8 to 15 percent
slopes, moderately
eroded
FeD2
Fairview sandy clay
C
8.9
0.4%
loam, 15 to 25 percent
slopes, moderately
eroded
FsE
Fairview -Stott Knob
B
1.8
0.1%
complex, 25 to 45
percent slopes
MsD
Mead owfie Id -Stott Knob
C
19.4
0.8%
complex, 15 to 25
percent slopes, very
stony
RbD
Rhodhiss-Bannertown
B
133.3
5.5%
complex, 15 to 25
percent slopes, very
rocky
RrE
Rhodhiss-Bannertown-
B
73.5
3.0%
Rock outcrop complex,
25 to 60 percent
slopes, very bouldery
SO
Stott Knob gravelly loam,
C
29.5
1.2%
15 to 25 percent
slopes, stony
USDA Natural Resources
r Conservation Service
Web Soil Survey
National Cooperative Soil Survey
Appendix B-29
DA2
8/3/2016
Page 4 of 6

Hydrologic Soil Group—Stokes County, North Carolina, and Surry County, North Carolina
Hydrologic Soil Group— Summary by Map Unit — Surry County, North Carolina (NC171)
Map unit symbol
Map unit name
Rating
Acres in AOI
Percent of AOI
StE
Stott Knob gravelly loam,
C
354.7
14.6%
25 to 45 percent
slopes, stony
TcC
Tate-Colvard complex, 0
B
8.1
0.3%
to 15 percent slopes,
frequently flooded
ToB
Toast coarse sandy
B
42.8
1.8%
loam, 2 to 8 percent
slopes, rocky
TtC
Toast-Bannertown
B
184.7
7.6%
complex, 8 to 15
percent slopes, very
rocky
WfC2
Woolwine-Fairview-
C
76.7
3.2%
Westfield complex, 8
to 15 percent slopes,
moderately eroded
WoD
Woolwine-Fairview-
C
202.4
8.3%
Westfield complex, 15
to 25 percent slopes,
stony
Subtotals for Soil Survey Area
1,240.9
51.1%
Totals for Area of Interest
2,428.8
100.0%
USDA Natural Resources
r Conservation Service
Web Soil Survey
National Cooperative Soil Survey
Appendix B-30
DA2
8/3/2016
Page 5 of 6

Hydrologic Soil Group—Stokes County, North Carolina, and Surry County, North Carolina
Description
Hydrologic soil groups are based on estimates of runoff potential. Soils are
assigned to one of four groups according to the rate of water infiltration when the
soils are not protected by vegetation, are thoroughly wet, and receive precipitation
from long -duration storms.
The soils in the United States are assigned to four groups (A, B, C, and D) and
three dual classes (A/D, B/D, and C/D). The groups are defined as follows:
Group A. Soils having a high infiltration rate (low runoff potential) when thoroughly
wet. These consist mainly of deep, well drained to excessively drained sands or
gravelly sands. These soils have a high rate of water transmission.
Group B. Soils having a moderate infiltration rate when thoroughly wet. These
consist chiefly of moderately deep or deep, moderately well drained or well drained
soils that have moderately fine texture to moderately coarse texture. These soils
have a moderate rate of water transmission.
Group C. Soils having a slow infiltration rate when thoroughly wet. These consist
chiefly of soils having a layer that impedes the downward movement of water or
soils of moderately fine texture or fine texture. These soils have a slow rate of water
transmission.
Group D. Soils having a very slow infiltration rate (high runoff potential) when
thoroughly wet. These consist chiefly of clays that have a high shrink -swell
potential, soils that have a high water table, soils that have a claypan or clay layer
at or near the surface, and soils that are shallow over nearly impervious material.
These soils have a very slow rate of water transmission.
If a soil is assigned to a dual hydrologic group (A/D, B/D, or C/D), the first letter is
for drained areas and the second is for undrained areas. Only the soils that in their
natural condition are in group D are assigned to dual classes.
Rating Options
Aggregation Method: Dominant Condition
Component Percent Cutoff: None Specified
Tie-break Rule: Higher
USDA Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
Appendix B-31
DA2
8/3/2016
Page 6 of 6

Big Creek 4 Land Use Table (Acres)
74.1% 125.9% 1
Big Creek Tributary #1
Big Creek III
A B C D
A
B
A B C
D
WOODS
134.0 2227.4 165.7
4.3
OPENSPACE
55.5
1440.9
26.4
IMPERV.
IMPERV.
2.7 112.0
WATER
WATER
6.8
TOTAL ACRES
192.2
3780.3
192.1
6.8
4164.6
4.6%
90.8%
4.6%
0.2%
74.1% 125.9% 1
Big Creek Tributary #1
Big Creek IV -A
A B C D
A
B
C D
WOODS
IMPERV.
19.6
4.3
OPENSPACE
TOTAL ACRES
13.1
6.3
IMPERV.
0.3
WATER
0.9
TOTAL ACRES
33.0
11.5
74.1% 125.9% 1
1 62.5% 137.5% 1
Big Creek Tributary #1
Big Creek IV -B
A B C D
A
B
C D
WOODS
IMPERV.
10.4
4.8
OPENSPACE
TOTAL ACRES
6.9
5.2
IMPERV.
0.1
WATER
0.5
TOTAL ACRES
17.4
10.5
1 62.5% 137.5% 1
*Added water to Impervious D Soils
44.5
27.9
73.5
Appendix B-32
Big Creek Tributary #1
A B C D
WOODS
59.9
OPENSPACE
13.3
IMPERV.
0.3
WATER
TOTAL ACRES
73.5
*Added water to Impervious D Soils
44.5
27.9
73.5
Appendix B-32

*Added water to Impervious D Soils
Appendix B-33
Big
Creek Tributary #2
A
B C D
WOODS
39.9
971.5 717.0
OPENSPACE
37.8
407.3 195.2
IMPERV.
1.2
40.7 17.0
WATER
I 1 1 1.9
TOTAL ACRES
78.9
1419.5 929.1 1.9
2429.4
3.2%
1 58.4% 138.2% 0.1
*Added water to Impervious D Soils
Appendix B-33

Big Creek III
4,165
Acres
6.51
Sq. Mi
PIEDMONT
PIEDMONT
TR -55 vs
TR -55 vs
LOWER
STD.
LOWER
UPPER
RECURRENCE REGIONAL
RECURRENCE
REGIONAL
REGRESSION
ERROR
TR -20 PEAK
REGRESSION
ERROR
LIMIT
LIMIT
(CFS)
INTERVAL (YRS)
REGRESION
(CFS)
(CFS)
(CFS)
DIFFERENCE
PEAK (CFS)
(%)
(CFS)
(CFS)
(%)
1
PEAK (CFS)
2 28 34.5%
(°�0)
1
15.8
-43.6%
5 55 41.2%
33
78
2
533 34.5%
349
717
418.6
-21.4%
5
955 41.2%
561
1348
908.2
-4.9%
10
1264 35.1%
820
1708
1394.9
10.4%
50
2033 39.6%
1228
2839
2876.9
41.5%
100
2361 41.9%
1371
3350
3630.7
53.8%
Big Creek IV -A
45
Acres
0.07
Sq. Mi
PIEDMONT
TR -55 vs
STD.
LOWER
UPPER
RECURRENCE REGIONAL
TR -20 PEAK
REGRESSION
ERROR
LIMIT
LIMIT
INTERVAL (YRS) REGRESION
(CFS)
DIFFERENCE
(%)
(CFS)
(CFS)
PEAK (CFS)
(%)
1
2 28 34.5%
18
38
15.8
-43.6%
5 55 41.2%
33
78
31.3
-43.5%
10 77 35.1%
50
104
44.8
-41.7%
50 134 39.6%
81
186
80.7
-39.6%
100 159 41.9%
93
226
97.5
-38.8%
Big Creek IV -B
28
Acres
0.04
Sq. Mi
PIEDMONT
TR -55 vs
STD.
LOWER
UPPER
RECURRENCE REGIONAL
TR -20 PEAK
REGRESSION
ERROR
LIMIT
LIMIT
INTERVAL (YRS) REGRESION
(CFS)
DIFFERENCE
(%)
(CFS)
(CFS)
PEAK (CFS)
(%)
1
2 21 34.5%
14
28
14.5
-29.9%
5 41 41.2%
24
58
26.8
-35.2%
10 58 35.1%
37
78
37.1
-35.6%
50 101 39.6%
61
141
63.3
-37.3%
100 121 41.9%
70
171
75.2
-37.7%
Appendix B-34

Big Creek Tributary #1
74
Acres
0.11
Sq. Mi
PIEDMONT
TR -55 vs
STD.
LOWER
UPPER
RECURRENCE
REGIONAL
TR -20 PEAK
REGRESSION
ERROR
LIMIT
LIMIT
INTERVAL (YRS)
REGRESION
(CFS)
DIFFERENCE
o
/o) (
CFS
()
CFS
()
PEAK (CFS)
N
1
2
39 34.5%
25
52
16
-58.7%
5
76 41.2%
45
107
41
-46.0%
10
105 35.1%
68
141
64.8
-38.1%
50
180 39.6%
109
252
129.6
-28.2%
100
215 41.9%
125
304
161
-25.0%
Big Creek Tributary #2
2,429
Acres
3.80
Sq. Mi
PIEDMONT
TR -55 vs
STD.
LOWER
UPPER
RECURRENCE
REGIONAL
TR -20 PEAK
REGRESSION
ERROR
LIMIT
LIMIT
INTERVAL (YRS)
REGRESION
(CFS)
DIFFERENCE
(%)
(CFS)
(CFS)
PEAK (CFS)
(%)
1
2
376 34.5%
246
505
625.7
66.6%
5
681 41.2%
400
961
1244.1
82.7%
10
906 35.1%
588
1225
1807.8
99.4%
50
1472 39.6%
889
2054
3345.4
127.3%
100
1714 41.9%
996
2432
4076.1
137.8%
Appendix B-35

APPENDIX B
Existing Conditions
Hydrologic Models
Appendix B-36

WinTR-20 Printed Page File Beginning of Input Data List
C:\Users\jeremy\Desktop\Big Creek 4.inp
WinTR-20: version
3.10
0
0
.01
0
Big Creek 4
.00413
0.00490
0.00569
0.00650
.00818
0.00906
SUB -AREA:
0.01087
.01278
0.01376
0.01477
0.01580
.01792
DA1
Reachl
0.02127
6.518
58.
2.513
Y
DA3
Reach2
0.03250
0.115
56.
.411
Y
DA4
Reach2
0.04551
0.0695
62.
.642
Y
DA5
Reach3
.06030
.04359
64.
.468
Y
DA2
Reach3
0.07494
3.789
62.
1.538
Y
STREAM REACH:
0.09097
0.09308
0.09520
.09952
0.10171
0.10392
Reachl
Reach2
XS -8
0.11766
1573.
1226.
Y
Reach2
Reach3
XS -18
0.13975
967.
605.
Y
Reach3
Outlet
XS -21
97.
97.
Y
STORM ANALYSIS:
1 -YR
3.00
1 yr sm
2
3.64
2 -YR
3.64
2 yr sm
2
3.64
5 -YR
4.64
5 yr sm
2
3.64
10 -YR
5.47
10_yr_sm
2
3.64
25 -YR
6.66
25 yr sm
2
3.64
50 -YR
7.67
50 yr sm
2
3.64
100 -YR
8.76
100 yr sm
2
3.64
STREAM CROSS SECTION:
XS -18
1062.72
1058.82
0.
0.
0.
.00414
1059.32
3.789
4.
16.
1061.22
144.204
42.95
25.
1062.72
387.671
83.45
29.
1063.5
399.128
136.108
106.02
1066.
2443.669
464.322
137.256
1076.
10000.
2000.
300.
XS -21
1062.4
1058.4
0.
0.
0.
0.0411
1058.9
11.94
4.
16.
1060.8
454.359
42.95
25.
1062.4
1284.646
86.15
29.
1064.1
2511.227
142.203
36.945
1076.
117613.25
4843.942
833.215
XS -8
1067.4
1063.4
0.
0.
0.
.0025
1063.9
2.945
4.
16.
1065.8
112.05
42.95
25.
1067.4
316.835
86.15
29.
1070.03
864.538
181.79
42.
1076.
6640.669
1438.65
364.519
RAINFALL DISTRIBUTION:
1 yr sm
0.0
0.00339
0.00733
0.01181
0.01685
0.02243
0.02856
0.03524
0.04247
0.05025
0.05857
0.06744
0.07686
0.08683
0.09735
0.10842
0.12003
0.13219
0.14490
.1
.000634
0.00129
0.00197
0.00267
.00413
0.00490
0.00569
0.00650
.00818
0.00906
0.00995
0.01087
.01278
0.01376
0.01477
0.01580
.01792
0.01902
0.02013
0.02127
.02361
0.02482
0.02604
0.02729
.02985
0.03117
0.03250
0.03386
.03664
0.03807
0.03951
0.04098
.04398
0.04551
0.04707
0.04865
.05187
0.05351
0.05517
0.05686
.06030
0.06205
0.06383
0.06562
.06928
0.07114
0.07303
0.07494
.07881
0.08079
0.08278
0.08479
.08889
0.09097
0.09308
0.09520
.09952
0.10171
0.10392
0.10616
11070
0�.113OQ B_.11532
0.11766
.12242
�� �'l"`
�
12726
0.12972
.13469
0.13721
0.13975
0.14232
.14864
0.15242
0.15625
0.16012

2 yr sm
0.16404
0.16801
0.17203
0.17609
0.18020
0.18435
0.18855
0.19280
0.19710
0.20144
0.20583
0.21192
0.21860
0.22588
0.23374
0.24220
0.25124
0.26088
0.27111
0.28192
0.29333
0.30843
0.32769
0.35482
0.39411
0.46878
0.60589
0.64518
0.67231
0.69157
0.70667
0.71808
0.72889
0.73912
0.74876
0.75780
0.76626
0.77412
0.78140
0.78808
0.79417
0.79856
0.80290
0.80720
0.81145
0.81565
0.81980
0.82391
0.82797
0.83199
0.83596
0.83988
0.84375
0.84758
0.85136
0.85510
0.85768
0.86025
0.86279
0.86531
0.86781
0.87028
0.87274
0.87517
0.87758
0.87997
0.88234
0.88468
0.88700
0.88930
0.89158
0.89384
0.89608
0.89829
0.90048
0.90265
0.90480
0.90692
0.90903
0.91111
0.91317
0.91521
0.91722
0.91921
0.92119
0.92314
0.92506
0.92697
0.92886
0.93072
0.93256
0.93438
0.93617
0.93795
0.93970
0.94143
0.94314
0.94483
0.94649
0.94813
0.94975
0.95135
0.95293
0.95449
0.95602
0.95753
0.95902
0.96049
0.96193
0.96336
0.96476
0.96614
0.96750
0.96883
0.97015
0.97144
0.97271
0.97396
0.97518
0.97639
0.97757
0.97873
0.97987
0.98098
0.98208
0.98315
0.98420
0.98523
0.98624
0.98722
0.98819
0.98913
0.99005
0.99094
0.99182
0.99267
0.99350
0.99431
0.99510
0.99587
0.99661
0.99733
0.99803
0.99871
0.999366
1.0
0.1
0.0
0.000625
0.00127
0.00194
0.00263
0.00335
0.00408
0.00484
0.00562
0.00642
0.00724
0.00809
0.00895
0.00984
0.01075
0.01169
0.01264
0.01362
0.01461
0.01564
0.01668
0.01774
0.01883
0.01994
0.02107
0.02222
0.02339
0.02459
0.02581
0.02705
0.02831
0.02959
0.03090
0.03222
0.03357
0.03494
0.03634
0.03775
0.03919
0.04065
0.04213
0.04363
0.04516
0.04671
0.04827
0.04987
0.05148
0.05311
0.05477
0.05645
0.05815
0.05987
0.06162
0.06338
0.06517
0.06698
0.06881
0.07067
0.07254
0.07444
0.07636
0.07830
0.08027
0.08225
0.08426
0.08629
0.08834
0.09041
0.09251
0.09463
0.09677
0.09893
0.10111
0.10332
0.10554
0.10779
0.11006
0.11236
0.11467
0.11701
0.11937
0.12175
0.12415
0.12657
0.12902
0.13149
0.13398
0.13649
0.13903
0.14158
0.14416
0.14789
0.15166
0.15549
0.15935
0.16327
0.16723
0.17124
0.17529
0.17940
0.18354
0.18774
0.19198
0.19627
0.20061
0.20499
0.21108
0.21776
0.22504
0.23291
0.24137
0.25043
0.26007
0.27032
0.28115
0.29258
0.30777
0.32717
0.35443
0.39384
0.46872
0.60616
0.64557
0.67283
0.69223
0.70742
0.71885
0.72968
0.73993
0.74957
0.75863
0.76709
0.77496
0.78224
0.78892
0.79501
0.79939
0.80373
0.80802
0.81226
0.81646
0.82060
0.82471
0.82876
0.83277
0.83673
0.84065
0.84451
0.84834
0.85211
0.85584
0.85842
0.86097
0.86351
0.86602
0.86851
0.87098
0.87343
0.87585
0.87825
0.88063
0.88299
0.88533
0.88764
0.88994
0.89221
0.89446
0.89668
0.89889
0.90107
0.90323
0.90537
0.90749
0.90959
0.91166
0.91371
0.91574
0.91775
0.91973
0.92170
0.92364
0.92556
0.92746
0.92933
0.93119
0.93302
0.93483
0.93662
0.93838
0.94013
0.94185
0.94355
0.94523
0.94689
0.94852
0.95013
0.95173
0.95329
0.95484
0.95637
0.95787
0.95935
0.96081
0.96225
0.96366
0.96506
0.96643
0.96778
0.96910
0.97041
0.97169
0.97295
0.97419
0.97541
0.97661
0.97778
0.97893
0.98006
0.98117
0.98226
0.98332
0.98436
0B-:98638
0.98736
0.98831
0.98925
00
99105
0.99191
0.99276
0.99358
0.99438
0.99516
0.99592
0.99665
0.99737
0.99806
0.99873
0.999375

5 yr sm
10 yr sm
1.0
0.1
0.0
0.000599
0.00122
0.00186
0.00253
0.00322
0.00393
0.00466
0.00542
0.00620
0.00700
0.00782
0.00867
0.00954
0.01043
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0.01323
0.01421
0.01522
0.01624
0.01729
0.01836
0.01945
0.02057
0.02171
0.02287
0.02405
0.02525
0.02648
0.02773
0.02900
0.03030
0.03162
0.03296
0.03432
0.03570
0.03711
0.03854
0.03999
0.04147
0.04297
0.04449
0.04603
0.04759
0.04918
0.05079
0.05242
0.05407
0.05575
0.05745
0.05917
0.06092
0.06268
0.06447
0.06629
0.06812
0.06998
0.07185
0.07376
0.07568
0.07763
0.07960
0.08159
0.08360
0.08564
0.08770
0.08978
0.09188
0.09401
0.09616
0.09833
0.10052
0.10274
0.10497
0.10724
0.10952
0.11183
0.11415
0.11650
0.11888
0.12127
0.12369
0.12613
0.12859
0.13108
0.13359
0.13612
0.13867
0.14125
0.14385
0.14763
0.15147
0.15536
0.15929
0.16327
0.16730
0.17138
0.17551
0.17968
0.18391
0.18818
0.19250
0.19686
0.20128
0.20574
0.21199
0.21885
0.22635
0.23447
0.24321
0.25259
0.26258
0.27321
0.28446
0.29634
0.31215
0.33267
0.36083
0.40023
0.47232
0.59977
0.63917
0.66733
0.68785
0.70366
0.71554
0.72679
0.73742
0.74741
0.75679
0.76553
0.77365
0.78115
0.78801
0.79426
0.79872
0.80314
0.80750
0.81182
0.81609
0.82032
0.82449
0.82862
0.83270
0.83673
0.84071
0.84464
0.84853
0.85237
0.85615
0.85875
0.86133
0.86388
0.86641
0.86892
0.87141
0.87387
0.87631
0.87873
0.88112
0.88350
0.88585
0.88818
0.89048
0.89276
0.89503
0.89726
0.89948
0.90167
0.90384
0.90599
0.90812
0.91022
0.91230
0.91436
0.91640
0.91841
0.92040
0.92237
0.92432
0.92624
0.92815
0.93002
0.93188
0.93371
0.93553
0.93732
0.93908
0.94083
0.94255
0.94425
0.94592
0.94758
0.94921
0.95082
0.95241
0.95397
0.95551
0.95703
0.95853
0.96001
0.96146
0.96289
0.96430
0.96568
0.96704
0.96838
0.96970
0.97100
0.97227
0.97352
0.97475
0.97595
0.97713
0.97829
0.97943
0.98055
0.98164
0.98271
0.98376
0.98478
0.98579
0.98677
0.98773
0.98866
0.98957
0.99046
0.99133
0.99218
0.99300
0.99380
0.99458
0.99534
0.99607
0.99678
0.99747
0.99814
0.99878
0.999401
1.0
0.1
0.0
0.000583
0.00119
0.00182
0.00247
0.00315
0.00385
0.00457
0.00532
0.00609
0.00688
0.00770
0.00854
0.00940
0.01029
0.01120
0.01213
0.01309
0.01407
0.01507
0.01610
0.01715
0.01823
0.01932
0.02044
0.02159
0.02276
0.02395
0.02516
0.02640
0.02766
0.02894
0.03025
0.03158
0.03294
0.03432
0.03572
0.03714
0.03859
0.04006
0.04156
0.04308
0.04462
0.04618
0.04777
0.04938
0.05102
0.05268
0.05436
0.05607
0.05780
0.05955
0.06132
0.06312
0.06495
0.06679
0.06866
0.07055
0.07247
0.07441
0.07637
0.07836
0.08037
0.08240
0.08446
0.08654
0.08864
0.09077
0.09292
0.09509
0.09729
0.09951
0.10175
0.10402
0.10631
0.10862
0.11096
0.11332
0.11571
0.11811
0.12054
0.12300
0.12548
0.12798
0.13050
0.13305
0.13562
0.13821
0.14083
0.14347
0.14614
0.15001
0.15393
0.15789
0.16191
0.16598
0.17009
0.17426
0.17847
0.18274
0.18705
0.19142
0.19583
0.20029
0.20480
0.20936
0.21573
0.22273
0.23037
0.23865
0.24756
0.25710
0.26729
0.27810
0.28956
0.30165
0.31789
OA33�
B_0.36755
0.40624
0.47514
0.59376
0
66088
0.68211
0.69835
0.71044
0.72190
0.73271
0.74290
0.75244
0.76135
0.76963
0.77727
0.78427

0.79064
0.79520
0.79971
0.80417
0.80858
0.81295
0.81726
0.82153
0.82574
0.82991
0.83402
0.83809
0.84211
0.84607
0.84999
0.85386
0.85653
0.85917
0.86179
0.86438
0.86695
0.86950
0.87202
0.87452
0.87700
0.87946
0.88189
0.88429
0.88668
0.88904
0.89138
0.89369
0.89598
0.89825
0.90049
0.90271
0.90491
0.90708
0.90923
0.91136
0.91346
0.91554
0.91760
0.91963
0.92164
0.92363
0.92559
0.92753
0.92945
0.93134
0.93321
0.93505
0.93688
0.93868
0.94045
0.94220
0.94393
0.94564
0.94732
0.94898
0.95062
0.95223
0.95382
0.95538
0.95692
0.95844
0.95994
0.96141
0.96286
0.96428
0.96568
0.96706
0.96842
0.96975
0.97106
0.97234
0.97360
0.97484
0.97605
0.97724
0.97841
0.97956
0.98068
0.98177
0.98285
0.98390
0.98493
0.98593
0.98691
0.98787
0.98880
0.98971
0.99060
0.99146
0.99230
0.99312
0.99391
0.99468
0.99543
0.99615
0.99685
0.99753
0.99818
0.99881
0.999417
1.0
25 yr sm
0.1
0.0
0.000622
0.00127
0.00194
0.00263
0.00335
0.00408
0.00485
0.00563
0.00644
0.00728
0.00814
0.00902
0.00992
0.01085
0.01180
0.01277
0.01377
0.01479
0.01584
0.01691
0.01800
0.01912
0.02026
0.02142
0.02261
0.02382
0.02505
0.02631
0.02759
0.02889
0.03022
0.03157
0.03294
0.03434
0.03576
0.03721
0.03868
0.04017
0.04169
0.04322
0.04479
0.04637
0.04798
0.04962
0.05127
0.05295
0.05466
0.05638
0.05814
0.05991
0.06171
0.06353
0.06537
0.06724
0.06914
0.07105
0.07299
0.07495
0.07694
0.07895
0.08098
0.08304
0.08512
0.08722
0.08935
0.09150
0.09367
0.09587
0.09809
0.10034
0.10261
0.10490
0.10721
0.10955
0.11191
0.11430
0.11671
0.11914
0.12160
0.12408
0.12658
0.12911
0.13166
0.13423
0.13683
0.13945
0.14210
0.14476
0.14746
0.15017
0.15413
0.15814
0.16219
0.16630
0.17046
0.17467
0.17892
0.18323
0.18759
0.19200
0.19646
0.20097
0.20553
0.21014
0.21480
0.22132
0.22848
0.23630
0.24478
0.25390
0.26368
0.27411
0.28519
0.29692
0.30931
0.32563
0.34718
0.37568
0.41355
0.47854
0.58645
0.62432
0.65282
0.67437
0.69069
0.70308
0.71481
0.72589
0.73632
0.74610
0.75522
0.76370
0.77152
0.77868
0.78520
0.78986
0.79447
0.79903
0.80354
0.80800
0.81241
0.81677
0.82108
0.82533
0.82954
0.83370
0.83781
0.84186
0.84587
0.84983
0.85254
0.85524
0.85790
0.86055
0.86317
0.86577
0.86834
0.87089
0.87342
0.87592
0.87840
0.88086
0.88329
0.88570
0.88809
0.89045
0.89279
0.89510
0.89739
0.89966
0.90191
0.90413
0.90633
0.90850
0.91065
0.91278
0.91488
0.91696
0.91902
0.92105
0.92306
0.92505
0.92701
0.92895
0.93086
0.93276
0.93463
0.93647
0.93829
0.94009
0.94186
0.94362
0.94534
0.94705
0.94873
0.95038
0.95202
0.95363
0.95521
0.95678
0.95831
0.95983
0.96132
0.96279
0.96424
0.96566
0.96706
0.96843
0.96978
0.97111
0.97241
0.97369
0.97495
0.97618
0.97739
0.97858
0.97974
0.98088
0.98200
0.98309
0.98416
0.98521
0.98623
0.98723
0.98820
0.98915
0.99008
0.99098
0.99186
0.99272
0.99356
0.99437
0.99515
0.99592
0.99665
0.99737
0.99806
0.99873
0.999378
1.0
50_yr_sm
0.1
0.0
0.000612
0.00125
0.00191
0.00259
0.00330
0.00404
0.00480
0.00558
0.00639
0.00722
0.00807
OA00� B_- 00986
0.01079
0.01174
0.01272
0
`' 01475
0.01580
0.01688
0.01798
0.01910
0.02025
0.02143
0.02262
0.02385
0.02509
0.02637
0.02766

0.02898
0.03033
0.03170
0.03309
0.03451
0.03595
0.03742
0.03891
0.04042
0.04196
0.04353
0.04512
0.04673
0.04837
0.05003
0.05172
0.05343
0.05517
0.05693
0.05871
0.06052
0.06235
0.06421
0.06609
0.06800
0.06993
0.07189
0.07387
0.07587
0.07790
0.07995
0.08203
0.08413
0.08626
0.08841
0.09059
0.09279
0.09501
0.09726
0.09953
0.10183
0.10415
0.10650
0.10887
0.11127
0.11369
0.11613
0.11860
0.12109
0.12361
0.12615
0.12872
0.13131
0.13393
0.13657
0.13923
0.14192
0.14463
0.14737
0.15013
0.15292
0.15696
0.16106
0.16521
0.16941
0.17367
0.17797
0.18233
0.18673
0.19119
0.19570
0.20027
0.20488
0.20955
0.21426
0.21903
0.22569
0.23301
0.24100
0.24965
0.25897
0.26895
0.27959
0.29090
0.30288
0.31551
0.33220
0.35444
0.38316
0.42013
0.48144
0.57987
0.61684
0.64556
0.66780
0.68449
0.69712
0.70910
0.72041
0.73105
0.74103
0.75035
0.75900
0.76699
0.77431
0.78097
0.78574
0.79045
0.79512
0.79973
0.80430
0.80881
0.81327
0.81767
0.82203
0.82633
0.83059
0.83479
0.83894
0.84304
0.84708
0.84987
0.85263
0.85537
0.85808
0.86077
0.86343
0.86607
0.86869
0.87128
0.87385
0.87639
0.87891
0.88140
0.88387
0.88631
0.88873
0.89113
0.89350
0.89585
0.89817
0.90047
0.90274
0.90499
0.90721
0.90941
0.91159
0.91374
0.91587
0.91797
0.92005
0.92210
0.92413
0.92613
0.92811
0.93007
0.93200
0.93391
0.93579
0.93765
0.93948
0.94129
0.94307
0.94483
0.94657
0.94828
0.94997
0.95163
0.95327
0.95488
0.95647
0.95804
0.95958
0.96109
0.96258
0.96405
0.96549
0.96691
0.96830
0.96967
0.97102
0.97234
0.97363
0.97491
0.97615
0.97738
0.97857
0.97975
0.98090
0.98202
0.98312
0.98420
0.98525
0.98628
0.98728
0.98826
0.98921
0.99014
0.99105
0.99193
0.99278
0.99361
0.99442
0.99520
0.99596
0.99670
0.99741
0.99809
0.99875
0.999388
1.0
100 yr sm
0.1
0.0
0.000661
0.00135
0.00206
0.00279
0.00355
0.00434
0.00515
0.00598
0.00684
0.00772
0.00863
0.00957
0.01053
0.01151
0.01252
0.01355
0.01461
0.01569
0.01680
0.01793
0.01909
0.02027
0.02148
0.02271
0.02397
0.02525
0.02655
0.02789
0.02924
0.03062
0.03203
0.03346
0.03491
0.03639
0.03790
0.03943
0.04098
0.04256
0.04417
0.04579
0.04745
0.04913
0.05083
0.05256
0.05431
0.05609
0.05789
0.05972
0.06157
0.06345
0.06535
0.06728
0.06923
0.07121
0.07321
0.07524
0.07729
0.07936
0.08146
0.08359
0.08574
0.08791
0.09011
0.09234
0.09459
0.09686
0.09916
0.10149
0.10384
0.10621
0.10861
0.11103
0.11348
0.11595
0.11845
0.12098
0.12352
0.12610
0.12869
0.13131
0.13396
0.13663
0.13933
0.14205
0.14480
0.14757
0.15036
0.15319
0.15603
0.15890
0.16303
0.16721
0.17145
0.17573
0.18007
0.18446
0.18890
0.19340
0.19794
0.20254
0.20719
0.21189
0.21664
0.22145
0.22631
0.23304
0.24043
0.24848
0.25717
0.26652
0.27653
0.28718
0.29849
0.31045
0.32306
0.33954
0.36149
0.38955
0.42522
0.48327
0.57478
0.61045
0.63851
0.66046
0.67694
0.68955
0.70151
0.71282
0.72347
0.73348
0.74283
0.75152
0.75957
0.76696
0.77369
0.77855
0.78336
0.78811
0.79281
0.79746
0.80206
0.80660
0.81110
0.81554
0.81993
0.82427
0.82855
0.83279
0.83697
0.84110
0.84397
0.84681
0.84964
0.85243
0.85520
0.85795
0 8606 B_�T 86337
0.86604
0.86869
0.87131
0
87648
0.87902
0.88155
0.88405
0.88652
0.88897
0.89139
0.89379
0.89616
0.89851
0.90084
0.90314

200 yr sm
500 yr sm
0.90541
0.90766
0.90989
0.91209
0.91426
0.91641
0.91854
0.92064
0.92271
0.92476
0.92679
0.92879
0.93077
0.93272
0.93465
0.93655
0.93843
0.94028
0.94211
0.94391
0.94569
0.94744
0.94917
0.95087
0.95255
0.95421
0.95583
0.95744
0.95902
0.96057
0.96210
0.96361
0.96509
0.96654
0.96797
0.96938
0.97076
0.97211
0.97345
0.97475
0.97603
0.97729
0.97852
0.97973
0.98091
0.98207
0.98320
0.98431
0.98539
0.98645
0.98748
0.98849
0.98947
0.99043
0.99137
0.99228
0.99316
0.99402
0.99485
0.99566
0.99645
0.99721
0.99794
0.99865
0.999339
1.0
0.1
0.0
0.000715
0.00145
0.00222
0.00301
0.00382
0.00466
0.00553
0.00642
0.00733
0.00827
0.00923
0.01022
0.01124
0.01227
0.01334
0.01443
0.01554
0.01668
0.01784
0.01903
0.02024
0.02148
0.02274
0.02403
0.02534
0.02668
0.02804
0.02943
0.03084
0.03227
0.03374
0.03522
0.03673
0.03827
0.03983
0.04142
0.04303
0.04466
0.04632
0.04801
0.04972
0.05146
0.05322
0.05500
0.05681
0.05865
0.06051
0.06239
0.06430
0.06623
0.06819
0.07018
0.07219
0.07422
0.07628
0.07836
0.08047
0.08261
0.08476
0.08695
0.08916
0.09139
0.09365
0.09593
0.09824
0.10057
0.10293
0.10531
0.10772
0.11015
0.11261
0.11509
0.11759
0.12013
0.12268
0.12526
0.12787
0.13050
0.13316
0.13584
0.13854
0.14128
0.14403
0.14681
0.14962
0.15245
0.15530
0.15818
0.16109
0.16402
0.16822
0.17248
0.17679
0.18115
0.18556
0.19002
0.19454
0.19911
0.20373
0.20841
0.21314
0.21792
0.22275
0.22763
0.23257
0.23940
0.24687
0.25500
0.26378
0.27322
0.28330
0.29404
0.30542
0.31746
0.33015
0.34649
0.36830
0.39595
0.43050
0.48529
0.56950
0.60405
0.63170
0.65351
0.66985
0.68254
0.69458
0.70596
0.71670
0.72678
0.73622
0.74500
0.75313
0.76060
0.76743
0.77237
0.77725
0.78208
0.78686
0.79159
0.79627
0.80089
0.80546
0.80998
0.81444
0.81885
0.82321
0.82752
0.83178
0.83598
0.83891
0.84182
0.84470
0.84755
0.85038
0.85319
0.85597
0.85872
0.86146
0.86416
0.86684
0.86950
0.87213
0.87474
0.87732
0.87987
0.88241
0.88491
0.88739
0.88985
0.89228
0.89469
0.89707
0.89943
0.90176
0.90407
0.90635
0.90861
0.91084
0.91305
0.91524
0.91739
0.91953
0.92164
0.92372
0.92578
0.92781
0.92982
0.93181
0.93377
0.93570
0.93761
0.93949
0.94135
0.94319
0.94500
0.94678
0.94854
0.95028
0.95199
0.95368
0.95534
0.95697
0.95858
0.96017
0.96173
0.96327
0.96478
0.96626
0.96773
0.96916
0.97057
0.97196
0.97332
0.97466
0.97597
0.97726
0.97852
0.97976
0.98097
0.98216
0.98332
0.98446
0.98557
0.98666
0.98773
0.98876
0.98978
0.99077
0.99173
0.99267
0.99358
0.99447
0.99534
0.99618
0.99699
0.99778
0.99855
0.999285
1.0
0.1
0.0
0.000761
0.00155
0.00236
0.00320
0.00406
0.00495
0.00586
0.00680
0.00777
0.00876
0.00977
0.01081
0.01188
0.01297
0.01409
0.01523
0.01640
0.01759
0.01881
0.02005
0.02132
0.02262
0.02394
0.02529
0.02666
0.02805
0.02947
0.03092
0.03240
0.03389
0.03542
0.03697
0.03854
0.04014
0.04177
0.04342
0.04509
0.04679
0.04852
0.05027
0.05205
0.05385
0.05568
0.05754
0.05942
0.06132
0.06325
0.06521
0.06719
0.06919
0.07122
00� B- 07536
0.07747
0.07961
0.08176
0
08616
0.08839
0.09065
0.09294
0.09525
0.09759
0.09995
0.10234
0.10475
0.10719
0.10965
0.11214

GLOBAL OUTPUT:
0.11466
0.11720
0.11976
0.12235
0.12497
0.12761
0.13028
0.13297
0.13569
0.13843
0.14120
0.14399
0.14681
0.14966
0.15253
0.15542
0.15834
0.16129
0.16426
0.16726
0.17028
0.17459
0.17895
0.18336
0.18782
0.19234
0.19691
0.20154
0.20621
0.21094
0.21573
0.22056
0.22545
0.23039
0.23539
0.24044
0.24738
0.25498
0.26322
0.27211
0.28164
0.29183
0.30266
0.31414
0.32627
0.33904
0.35533
0.37714
0.40428
0.43729
0.48777
0.56271
0.59572
0.62286
0.64467
0.66096
0.67373
0.68586
0.69734
0.70817
0.71836
0.72789
0.73678
0.74502
0.75262
0.75956
0.76461
0.76961
0.77455
0.77944
0.78427
0.78906
0.79379
0.79846
0.80309
0.80766
0.81218
0.81664
0.82105
0.82541
0.82972
0.83274
0.83574
0.83871
0.84166
0.84458
0.84747
0.85034
0.85319
0.85601
0.85880
0.86157
0.86431
0.86703
0.86972
0.87239
0.87503
0.87765
0.88024
0.88280
0.88534
0.88786
0.89035
0.89281
0.89525
0.89766
0.90005
0.90241
0.90475
0.90706
0.90935
0.91161
0.91384
0.91605
0.91824
0.92039
0.92253
0.92464
0.92672
0.92878
0.93081
0.93281
0.93479
0.93675
0.93868
0.94058
0.94246
0.94432
0.94615
0.94795
0.94973
0.95148
0.95321
0.95491
0.95658
0.95823
0.95986
0.96146
0.96303
0.96458
0.96611
0.96760
0.96908
0.97053
0.97195
0.97334
0.97471
0.97606
0.97738
0.97868
0.97995
0.98119
0.98241
0.98360
0.98477
0.98591
0.98703
0.98812
0.98919
0.99023
0.99124
0.99223
0.99320
0.99414
0.99505
0.99594
0.99680
0.99764
0.99845
0.999239
1.0
YN N YN N
WinTR-20 Printed Page File End of Input Data List
Big Creek 4
Name of printed page file:
C:\Users\jeremy\Desktop\Big Creek 4.out
STORM 1 -YR
Area or
Drainage
Rain Gage
Runoff
------------
Peak
Flow ------------
Reach
Area
ID or
Amount
Elevation
Time
Rate
Rate
Identifier
(sq mi)
Location
(in)
(ft)
(hr)
(cfs)
(csm)
DA1
6.518
0.274
14.39
191.1
29.32
Reachl
6.518
Upstream
0.274
1066.42
14.39
191.1
29.32
Reachl
6.518
Downstream
0.274
1066.42
14.39
191.1
29.32
DA3
0.115
0.220
12.51
5.0
43.31
DA4
0.069
0.398
12.57
7.6
108.92
Reach2
6.702
Upstream
0.274
1061.53
14.40
194.6
29.03
Reach2
6.702
Downstream
0.274
1061.53
14.43
194.4
29.01
DA5
0.044
0.469
12.41
7.4
170.59
DA2
3.789
0.398
13.38
246.5
65.05
Reach3
10.535
Upstream
0.320
1060.46
13.75
375.6
35.65
Reach3
10.535
Downstream
0.320
1060.46
13.75
375.6
35.65
OUTLET
10.535
0.320
13.75
375.6
35.65
Ap�enYix B243YR
Area or
Drainage
Rain Gage
Runoff
------------
Peak
Flow ------------
Reach
Area
ID or
Amount
Elevation
Time
Rate
Rate

Identifier
(sq mi)
Location
(in)
(ft)
(hr)
(cfs)
(csm)
DA1
6.518
0.509
14.13
418.6
64.22
Reachl
6.518
Upstream
0.509
1067.89
14.13
418.6
64.22
Reachl
6.518
Downstream
0.509
1067.88
14.13
417.7
64.08
DA3
0.115
0.431
12.39
15.9
138.11
DA4
0.069
0.682
12.51
15.8
228.01
Reach2
6.702
Upstream
0.510
1063.53
14.13
424.0
63.26
Reach2
6.702
Downstream
0.510
1063.53
14.21
423.7
63.22
DA5
0.044
0.777
12.38
14.5
333.27
DA2
3.789
0.682
13.19
491.8
129.81
Reach3
10.535
Upstream
0.573
1061.45
13.51
790.6
75.04
Reach3
10.535
Downstream
0.573
1061.45
13.51
790.6
75.04
OUTLET
10.535
0.573
13.51
790.6
75.04
STORM 5 -YR
Area or
Drainage
Rain Gage
Runoff
------------
Peak
Flow ------------
Reach
Area
ID or
Amount
Elevation
Time
Rate
Rate
Identifier
(sq mi)
Location
(in)
(ft)
(hr)
(cfs)
(csm)
DA1
6.518
0.976
13.98
908.2
139.34
Reachl
6.518
Upstream
0.976
1070.08
13.98
908.2
139.34
Reachl
6.518
Downstream
0.976
1070.07
13.98
907.0
139.15
DA3
0.115
0.862
12.34
41.0
356.51
DA4
0.069
1.221
12.51
31.3
450.37
Reach2
6.702
Upstream
0.977
1064.14
13.98
919.1
137.13
Reach2
6.702
Downstream
0.977
1064.14
14.03
918.6
137.05
DA5
0.044
1.352
12.35
26.8
614.32
DA2
3.789
1.221
13.16
976.0
257.60
WinTR-20 Version 3.10
Page
1
08/19/2016
8:18
Appendix B-44

Big Creek 4
Area or
Drainage
Rain Gage
Runoff
------------
Peak
Flow ------------
Reach
Area
ID or
Amount
Elevation
Time
Rate
Rate
Identifier
(sq mi)
Location
(in)
(ft)
(hr)
(cfs)
(csm)
Reach3
10.535
Upstream
1.066
1062.93
13.46
1664.1
157.96
Reach3
10.535
Downstream
1.066
1062.93
13.46
1664.1
157.95
OUTLET
10.535
1.066
13.46
1664.1
157.95
STORM 10 -YR
Area or
Drainage
Rain Gage
Runoff
------------
Peak
Flow ------------
Reach
Area
ID or
Amount
Elevation
Time
Rate
Rate
Identifier
(sq mi)
Location
(in)
(ft)
(hr)
(cfs)
(csm)
DA1
6.518
1.436
13.87
1394.9
214.01
Reachl
6.518
Upstream
1.436
1070.58
13.87
1394.9
214.01
Reachl
6.518
Downstream
1.436
1070.57
13.87
1391.4
213.47
DA3
0.115
1.293
12.34
64.8
563.79
DA4
0.069
1.736
12.50
44.8
645.05
Reach2
6.702
Upstream
1.437
1064.74
13.87
1409.9
210.36
Reach2
6.702
Downstream
1.437
1064.74
13.92
1409.7
210.33
DA5
0.044
1.894
12.34
37.1
850.50
DA2
3.789
1.736
13.15
1421.1
375.07
Reach3
10.535
Upstream
1.546
1064.10
13.43
2512.0
238.44
Reach3
10.535
Downstream
1.546
1064.10
13.43
2512.0
238.44
OUTLET
10.535
1.546
13.43
2512.0
238.44
STORM 25 -YR
Area or
Drainage
Rain Gage
Runoff
------------
Peak
Flow ------------
Reach
Area
ID or
Amount
Elevation
Time
Rate
Rate
Identifier
(sq mi)
Location
(in)
(ft)
(hr)
(cfs)
(csm)
DA1
6.518
2.181
13.87
2171.4
333.14
Reachl
6.518
Upstream
2.181
1071.38
13.87
2171.4
333.14
Reachl
6.518
Downstream
2.181
1071.38
13.87
2171.4
333.14
DA3
0.115
2.000
12.33
100.7
875.63
DA4
0.069
2.554
12.45
64.7
930.59
Reach2
6.702
Upstream
2.182
1065.70
13.88
2197.1
327.80
Reach2
6.702
Downstream
2.182
1065.70
13.91
2196.2
327.67
DA5
0.044
2.745
12.36
51.8
1188.06
DA2
3.789
2.554
13.12
2095.3
552.99
Reach3
10.535
Upstream
2.318
1064.24
13.42
3843.4
364.82
Reach3
10.535
Downstream
2.318
1064.24
13.42
3843.3
364.81
OUTLET
10.535
2.318
13.42
3843.3
364.81
STORM 50 -YR
Area or
Drainage
Rain Gage
Runoff
------------
Peak
Flow ------------
Reach
Area
ID or
Amount
Elevation
Time
Rate
Rate
Identifier
(sq mi)
Location
(in)
(ft)
(hr)
(cfs)
(csm)
DA1
6.518
2.875
13.81
2876.9
441.38
Reachl
6.518
Upstream
2.875
1072.11
13.81
2876.9
441.38
Reachl
6.518
Downstream
2.875
1072.10
13.81
2871.7
440.58
DA3
0.115
2.665
12.30
129.6
1126.75
WinTR-20 Version 3.10
Page
2
08/19/2016
8:18
Appendix B-45

Big Creek 4
Area or
Drainage
Rain Gage
Runoff
------------
Peak
Flow ------------
Reach
Area
ID or
Amount
Elevation
Time
Rate
Rate
Identifier
(sq mi)
Location
(in)
(ft)
(hr)
(cfs)
(csm)
DA4
0.069
3.303
12.45
80.7
1161.69
Reach2
6.702
Upstream
2.876
1066.61
13.83
2906.8
433.68
Reach2
6.702
Downstream
2.876
1066.61
13.86
2906.1
433.59
DA5
0.044
3.520
12.35
63.3
1452.55
DA2
3.789
3.303
13.06
2680.4
707.41
Reach3
10.535
Upstream
3.032
1064.36
13.37
5024.3
476.91
Reach3
10.535
Downstream
3.032
1064.36
13.37
5024.1
476.89
OUTLET
10.535
3.032
13.37
5024.1
476.89
STORM 100 -YR
Area or
Drainage
Rain Gage
Runoff
------------
Peak
Flow ------------
Reach
Area
ID or
Amount
Elevation
Time
Rate
Rate
Identifier
(sq mi)
Location
(in)
(ft)
(hr)
(cfs)
(csm)
DA1
6.518
3.674
13.76
3630.7
557.02
Reachl
6.518
Upstream
3.674
1072.89
13.76
3630.7
557.02
Reachl
6.518
Downstream
3.674
1072.88
13.92
3619.1
555.25
DA3
0.115
3.435
12.31
161.0
1400.21
DA4
0.069
4.154
12.46
97.5
1402.95
Reach2
6.702
Upstream
3.674
1067.61
13.77
3662.8
546.48
Reach2
6.702
Downstream
3.674
1067.61
13.82
3662.2
546.40
DA5
0.044
4.396
12.35
75.2
1725.39
DA2
3.789
4.154
13.08
3285.1
867.01
Reach3
10.535
Upstream
3.850
1064.49
13.38
6270.2
595.17
Reach3
10.535
Downstream
3.850
1064.49
13.38
6270.0
595.15
OUTLET
10.535
3.850
13.38
6270.0
595.15
WinTR-20 Version 3.10
Page 3
Appendix B-46
08/19/2016 8:18

Big Creek 4
Area or
Drainage
-----------
Peak
Flow by Storm
-----------
Reach
Area
1 -YR
2 -YR
5 -YR
10 -YR
25 -YR
Identifier
(sq mi)
(cfs)
(cfs)
(cfs)
(cfs)
(cfs)
DA1
6.518
191.1
418.6
908.2
1394.9
2171.4
DA3
0.115
5.0
15.9
41.0
64.8
100.7
DA4
0.069
7.6
15.8
31.3
44.8
64.7
DA5
0.044
7.4
14.5
26.8
37.1
51.8
DA2
3.789
246.5
491.8
976.0
1421.1
2095.3
Reachl
6.518
191.1
418.6
908.2
1394.9
2171.4
DOWNSTREAM
191.1
417.7
907.0
1391.4
2171.4
Reach2
6.702
194.6
424.0
919.1
1409.9
2197.1
DOWNSTREAM
194.4
423.7
918.6
1409.7
2196.2
Reach3
10.535
375.6
790.6
1664.1
2512.0
3843.4
DOWNSTREAM
375.6
790.6
1664.1
2512.0
3843.3
OUTLET
10.535
375.6
790.6
1664.1
2512.0
3843.3
Area or
Drainage
-----------
Peak
Flow by Storm
-----------
Reach
Area
50 -YR
100 -YR
Identifier
(sq mi)
(cfs)
(cfs)
(cfs)
(cfs)
(cfs)
DA1
6.518
2876.9
3630.7
DA3
0.115
129.6
161.0
DA4
0.069
80.7
97.5
DA5
0.044
63.3
75.2
DA2
3.789
2680.4
3285.1
Reachl
6.518
2876.9
3630.7
DOWNSTREAM
2871.7
3619.1
Reach2
6.702
2906.8
3662.8
DOWNSTREAM
2906.1
3662.2
Reach3
10.535
5024.3
6270.2
DOWNSTREAM
5024.1
6270.0
OUTLET
10.535
5024.1
6270.0
WinTR-20 Version 3.10
Page 4 08/19/2016 8:18
Appendix B-47

APPENDIX C
Regional Regression Equations
Appendix B-48

BIG CREEK IV REGRESSION ANALYSIS
Big Creek III
4,165
Acres
6.51
Sq. Mi
RECURR PIEDMONT
TR -55 vs
STD.
LOWER
UPPER
TR -20
ENCE REGIONAL
REGRESSION
ERROR
LIMIT
LIMIT
PEAK
INTERNA REGRESION
DIFFERENCE
(%)
(CFS)
(CFS)
(CFS)
L (YRS) PEAK (CFS)
(%)
1
2 533 34.5%
349
717
418.6
-21.4%
5 955 41.2%
561
1348
908.2
-4.9%
10 1264 35.1%
820
1708
1394.9
10.4%
50 1 2033 39.6%
1228
2839
2876.9
41.5%
100 1 2361 41.9%
1371
3350
3630.7
53.8%
Big Creek IV -A
45
Acres
0.07
Sq. Mi
RECURR PIEDMONT
TR -55 vs
STD.
LOWER
UPPER
TR -20
ENCE REGIONAL
REGRESSION
ERROR
LIMIT
LIMIT
PEAK
INTERNA REGRESION
DIFFERENCE
(%)
(CFS)
(CFS)
(CFS)
L (YRS) PEAK (CFS)
(%)
1
2 28 34.5%
18
38
15.8
-43.6%
5 55 41.2%
33
78
31.3
-43.5%
10 77 35.1%
50
104
44.8
-41.7%
50 1 134 39.6%
81
1 186
80.7
-39.6%
100 1 159 41.9%
93
1 226
97.5
-38.8%
Big Creek IV -B
28
Acres
0.04
Sq. Mi
RECURR PIEDMONT
TR -55 vs
STD.
LOWER
UPPER
TR -20
ENCE REGIONAL
REGRESSION
ERROR
LIMIT
LIMIT
PEAK
INTERNA REGRESION
DIFFERENCE
(%)
(CFS)
(CFS)
(CFS)
L (YRS) PEAK (CFS)
(%)
1
2 21 34.5%
14
28
14.5
-29.9%
5 41 41.2%
24
58
26.8
-35.2%
10 58 35.1%
37
78
37.1
-35.6%
50 1 101 39.6%
1 61
1 141
63.3
-37.3%
100 1 121 41.9%
1 70
1 171
75.2
-37.7%
Appendix B-49

Big
Creek Tributary #1
74
Acres
0.11
Sq. Mi
RECURR
PIEDMONT
20%DAr"'
44.7(D.4)°-7"
123(DA 7
TR -55 vs
10
STD.
LOWER
UPPER
TR -20
295 D.4- P
ENCE
REGIONAL
398(D.4Y--"
77.6(D.4}°.-
245(DA
REGRESSION
2
ERROR
LIMIT
LIMIT
PEAK
575(D.4P`
INTERNA
REGRESION
575(DAj-7u3
105(DAP-733
3"DA"
DIFFERENCE
0.5
(%)
(CFS)
(CFS)
(CFS)
891(DA) 9
L (YRS)
PEAK (CFS)
794(fDA"
138(DAP-
55t1(DA"3
(%)
1
2
39 34.5%
25
52
16
-58.7%
5
76 41.2%
45
107
41
-46.0%
10
105 35.1%
68
141
64.8
-38.1%
50
180 39.6%
109
252
129.6
-28.2%
100
215 41.9%
125
304
161
-25.0%
Big
Creek Tributary #2
2,429
Acres
3.80
Sq. Mi
RECURR
PIEDMONT
20%DAr"'
44.7(D.4)°-7"
123(DA 7
TR -55 vs
10
STD.
LOWER
UPPER
TR -20
295 D.4- P
ENCE
REGIONAL
398(D.4Y--"
77.6(D.4}°.-
245(DA
REGRESSION
2
ERROR
LIMIT
LIMIT
PEAK
575(D.4P`
INTERNA
REGRESION
575(DAj-7u3
105(DAP-733
3"DA"
DIFFERENCE
0.5
(%)
(CFS)
(CFS)
(CFS)
891(DA) 9
L (YRS)
PEAK (CFS)
794(fDA"
138(DAP-
55t1(DA"3
(%)
1
2
376 34.5%
246
505
491.8
31.0%
5
681 41.2%
400
961
976
43.3%
10
906 35.1%
588
1225
1421.1
56.8%
50
1472 39.60Y(o
889
2054
1 2680.4
1 8 2. 1 %
100
1714 41.9%
996
2432
1 3285.1
1 91.7%
Table 8. Regional FloaSd-freqLien cy equations Far rurali, ungaged streams with drainage basins that are within
one hydrologic; region.
[DA, the dra¢nage urea in square milml
Purr;ant Hydrologic region (shown in figura.5 end 7�
chance
exceedance 1 2 3 4 5
50
158(1-4 V-
1 ](RD -4 f-
25.7(D,4? --J-
60-3(DA)a-9
91.- (DA -10`49
?0
295(D!4? -'2"
20%DAr"'
44.7(D.4)°-7"
123(DA 7
200(LDA 7
10
398(D-4)-'?
?8!1 DA 73fi
58-9(D.4?-
174(D4 -1-L7
295 D.4- P
4
537(D.4P-
398(D.4Y--"
77.6(D.4}°.-
245(DA
447{DA"
2
661(Lk4"
479(DAP71.11
91.2(D.4?-
309(DA"
575(D.4P`
776(DA)°.sas
575(DAj-7u3
105(DAP-733
3"DA"
724(DA"
0.5
8.91(D4f--
661 (DA)--
120(D. )P-
447(£DAr-"4
891(DA) 9
0:2
1p072(,Cll.4""
794(fDA"
138(DAP-
55t1(DA"3
1,148(DAr-3
Table 9. Average variance of prediction and standard error aF
prediction for the regional regression equations.
Percent chance Average warianee Average stand'a id
exceedance of Prediction error of prediction
(lag units I (percent)
Sara
0.021
3 4. 5
20
0.0 :
34
10
35.1
4
0.025
37.5
2
0.028
39. 6
1
0.031
41.9
0.5
0.034
44.3
0.2
0.039
47.7
Appendix B-50

APPENDIX D
Existing/Proposed Hydraulic
Models & Results
Appendix B-51

HEC -RAS Plan_ EXBG
Appendix B-52
---------------
---------------
---------------
®��Mffrmm®�"
�
ow.r. M., M,����
---------------
---------------
---------------
Appendix B-52

HEC -RAS Plan: EXBG
Appendix B-53
--------------
---------------
MENUMM
--------------
--------------
®�M��
---------------
--------------
--------------
Appendix B-53

HEC -RAS Plan: EXBG
Appendix B-54
---------------
---------------
---------------
mrm-Mwm®��
NEW M..
-Mmrmmmmffrmm®'
OEM wmmmmm�
---------------
---------------
Appendix B-54

Appendix B-55
BIG CREEK IV Plan: EXISTING 8/19/2016
BIG CREEK REACH 2--�
BIG CREEK REACH 1
1076
Legend
WS 100 - YR
IR
1074
WS 50 - YR
■
WS 25 - YR
WS 10 YR
1072
�
WS 5 -YR
WS 2 - YR
1070
WS 1 -YR
■
Ground
1068
1066
LU
1064
1062
1060
1058
� N M V LO (D
O N M V' � M r W 07 O O
I- M O � r r r � � � N N
1056
T�TrT�r�
0 500 1000
1500 2000 2500 3000
3500
Main Channel Distance (ft)
Appendix B-55

Appendix B-56
BIG CREEK IV Plan: EXISTING 8/19/2016
TRIB#1 EX. THALWEG TRIB
1071
Legend
WS 100 - YR
_
WS 50 - YR
1070
WS 25 - YR
WS 10 -YR
WS 5 -YR
1069-
WS 2 -YR
WS 1 -YR
■
Ground
1068
1067 -
LU
1066
1065
1064
N N
1063-
063
0
0
20 40 60 80
100
Main Channel Distance (ft)
Appendix B-56

Appendix B-57
BIG CREEK IV Plan: EXISTING 8/19/2016
TRIB#2 EX. THALWEG TRIB
1070
Legend
WS 100 -YR
•
WS 50 - YR
1068
WS 25 - YR
WS 10 - YR
WS 5 -YR
WS 2 -YR
1066
WS 1 -YR
■
Ground
1064
c
0
m
W
1062-
1060
1058
M V u7 U�
1056
0 100 200 300 400
500
Main Channel Distance (ft)
Appendix B-57

Appendix B-58
BIG CREEK IV Plan: EXISTING 8/19/2016
River = BIG CREEK Reach = REACH 1 RS = 20.7 ADDED XS
.07
.055 .04 .07
1078
Legend
WS 100 - YR
•
WS 50 - YR
WS 25 - YR
1076
WS 10 - YR
WS 5 YR
•
WS2-YR
WS1-YR
1074
Ground
Levee
•
Bank Sta
1072 -
LU
1070-
07010681066
1068-
1066
0
100 200 300 400
500
Station (ft)
Appendix B-58

Appendix B-59
BIG CREEK IV Plan: EXISTING 8/19/2016
River = BIG CREEK Reach = REACH 1 RS = 20.5 ADDED XS
.07
.055 .04 .07
1078
Legend
WS 100 - YR
•
WS 50 - YR
WS 25 - YR
1076
WS 10 - YR
WS 5 YR
•
WS2-YR
WS1-YR
1074
Ground
Levee
•
Bank Sta
1072 -
LU
1070-
070106810660
1068-
1066-
0
100 200 300 400
500
Station (ft)
Appendix B-59

Appendix B-60
BIG CREEK IV Plan: EXISTING 8/19/2016
River = BIG CREEK Reach = REACH 1 RS = 20 XS -1
07
J4 .055
.04 1- � .07
1084
Legend
WS 100 - YR
•
WS 50 - YR
1082
WS 25 - YR
WS 10 - YR
1080
WS 5 YR
•
WS2-YR
WS1-YR
1078
Ground
E
Levee
•
Bank Sta
1076
0
0
m
LU
1074-
0741072107010681066-100
1072-
1070-
1068-
1066-
-1000
100 200 300
400 500
Station (ft)
Appendix B-60

Appendix B-61
BIG CREEK IV Plan: EXISTING 8/19/2016
River = BIG CREEK Reach = REACH 1 RS = 19 XS -2
.07 .055 � 04.07
1078
Legend
WS 100 - YR
•
WS 50 - YR
WS 25 - YR
1076
WS 10 - YR
WS 5 YR
•
WS2-YR
WS1-YR
1074
Ground
Levee
•
Bank Sta
0
.F --
1072 -
LU
1070-
07010681066
1068-
1066
-200
-100 0 100 200 300 400
500
Station (ft)
Appendix B-61

Appendix B-62
BIG CREEK IV Plan: EXISTING
8/19/2016
River = BIG CREEK Reach = REACH 1
RS = 18 XS -3
07 -F
.055
=" .04 -f
.055 .07
1078
Legend
F
WS 100 - YR
•
WS 50 - YR
1076
WS 25 - YR
WS 10 - YR
WS 5 YR
•
WS2-YR
1074
WS1-YR
■
Ground
E
Levee
•
1072
Bank Sta
0
m
LU
1070-
070106810661064
1068-
1066-
1064-1
0 100
200 300
400
500
600
Station (ft)
Appendix B-62

Appendix B-63
BIG CREEK IV Plan: EXISTING 8/19/2016
River = BIG CREEK Reach = REACH 1 RS = 17 XS -4
.07 JL.055
"�" 04-41—.055
.07
1078
Legend
F
WS 100 - YR
•
WS 50 - YR
1076
WS 25 - YR
WS 10 - YR
WS 5YR
•
WS2-YR
1074 -
074WS1-YR
WS 1 -YR
■
Ground
Levee
•
1072
Bank Sta
0
m
LU
1070-
070106810661064
1068-
1066-
1064
0 100
200 300 400 500
600
700
Station (ft)
Appendix B-63

Appendix B-64
BIG CREEK IV Plan: EXISTING 8/19/2016
River = BIG CREEK Reach = REACH 1 RS = 16 XS -5
.07
.055
.04 .07
1078
Legend
F
WS 100 - YR
•
WS 50 - YR
1076
WS 25 - YR
WS 10 - YR
WS 5 YR
•
WS2-YR
1074 -
074WS1-YR
WS 1 -YR
Ground
•
Bank Sta
1072-
0721070106810661064
1070-
1068-
1066-
1064-1
0 100
200 300 400
500
600
Station (ft)
Appendix B-64

Appendix B-65
BIG CREEK IV Plan: EXISTING 8/19/2016
River = BIG CREEK Reach = REACH 1 RS = 15 XS - 6
.07
.055 J, .04 �� .055 .07
1080
Legend
WS 100 - YR
•
WS 50 - YR
1078
�
WS 25 - YR
WS 10 - YR
WS 5 YR
1076
`
WS2-YR
WS1-YR
■
Ground
1074
Bank Sta
1072-
0721070106810661064
1070-
1068-
1066-
1064
0 100
200 300 400 500
600
Station (ft)
Appendix B-65

Appendix B-66
BIG CREEK IV
Plan: EXISTING 8/19/2016
River = BIG CREEK
Reach = REACH 1 RS = 14 XS -7
.07 .055
{ .04 .055 "' 07
1076
Legend
F
WS 100 - YR
•
WS 50 - YR
1074
WS 25 - YR
WS 10 - YR
WS 5 YR
•
WS2-YR
1072
WS1-YR
■
Ground
Levee
•
1070
Bank Sta
0
m
LU
1068-
068106610641062
1066-
1064-
1062-1
0 100 200
300 400 500
Station (ft)
Appendix B-66

Appendix B-67
BIG CREEK IV Plan: EXISTING 8/19/2016
River = BIG CREEK Reach = REACH 1 RS = 13 XS -8
.07 .055 .04 ---Jk .055 "� .07
1076
Legend
WS 100 - YR
•
WS 50 - YR
WS 25 - YR
1074
WS 10 - YR
WS 5 YR
•
WS2-YR
WS1-YR
1072
Ground
Levee
•
Bank Sta
0
1070 -
LU
1068-
06810661064
1066-
1064
0 100 200 300 400 500
600
Station (ft)
Appendix B-67

Appendix B-68
BIG CREEK IV
Plan: EXISTING 8/19/2016
River = BIG CREEK
Reach = REACH 1 RS = 12 XS -9
.07 .055
04 055 .07
}
1080
Legend
F
WS 100 - YR
•
WS 50 - YR
1078
WS 25 - YR
WS 10 - YR
1076
WS 5 YR
•
WS2-YR
WS1-YR
1074
Ground
•
Bank Sta
1072
0
0
m
LU
1070-
07010681066
1068-
1066
10641
1062
0 100 200
300 400
500
Station (ft)
Appendix B-68

Appendix B-69
BIG CREEK IV Plan: EXISTING 8/19/2016
River = BIG CREEK Reach = REACH 1 RS = 11 XS -10
07 .055 �� .04 .055 .07
1078
Legend
F
WS 100 - YR
•
WS 50 - YR
1076
�
WS 25 - YR
WS 10 - YR
WS 5 YR
1074
`
WS2-YR
WS1-YR
■
Ground
1072
Bank Sta
1070
w
1068
1066
1064-
1062
-
0
50 100 150 200 250 300 350
400
Station (ft)
Appendix B-69

Appendix B-70
BIG CREEK IV Plan: EXISTING 8/19/2016
River = BIG CREEK Reach = REACH 1 RS = 10 XS - 11
—.07 .055 .04 .055 .07
1078
Legend
WS 100 - YR
WS 50 - YR
1076
■
WS 25 - YR
WS 10 - YR
1074
WS 5 - YR
WS2-YR
WS1-YR
1072
Ground
Levee
A
Ineff
1070
•
0
Bank Sta
0
w
1068-
06810661064
1066-
1064
1062
1060
T
0
100 200 300 400
500
Station (ft)
Appendix B-70

Appendix B-71
BIG CREEK IV Plan: EXISTING 8/19/2016
River = BIG CREEK Reach = REACH 1 RS = 9 XS -12
.07 .055 "L' .04 �� .055 "� .07
1076
Legend
F
WS 100 - YR
•
WS 50 - YR
1074
WS 10 - YR
t
WS 25 - YR
WS 5 YR
•
WS2-YR
1072 -
072WS1-YR
WS 1 -YR
■
Ground
E
Levee
•
1070
Bank Sta
0
m
LU
1068-
068106610641062
1066-
1064-
1062
0 100 200 300 400
500
Station (ft)
Appendix B-71

BIG CREEK IV Plan: EXISTING 8/19/2016
River = BIG CREEK Reach = REACH 1 RS = 8 XS -13
.07 .055 J, .04 =- .055 ��.07
1078
Legend
F
WS 100 - YR
•
1076 WS 50 - YR
WS 25 - YR
WS 10 - YR
1074 WS 5 YR
•
WS2-YR
WS1-YR
1072
Ground
E
Levee
Ban•k Sta
1070-
0
070 0
m
LU 1068-
1066-
1064
06810661064
10621
1060 T T T T Tr
0 100 200 300 400 500 600
Station (ft)
Appendix B-72

Appendix B-73
BIG CREEK IV Plan: EXISTING 8/19/2016
River = BIG CREEK Reach = REACH 1 RS = 7 XS -14
f
07.055
- .04 .055 .07
1076
F
Legend
F
WS 100 - YR
•
WS 50 - YR
1074
�
WS 25 - YR
WS 10 - YR
WS 5 YR
1072
`
WS2-YR
WS1-YR
■
Ground
1070
Levee
•
Bank Sta
0
1068 -
LU
1066
1064-
06410621060
1062-
1060
0
100
200 300 400 500 600
700
Station (ft)
Appendix B-73

Appendix B-74
BIG CREEK IV Plan: EXISTING 8/19/2016
River = BIG CREEK Reach = REACH 2 RS = 6 XS -15
.07 �
.055 = .04 �� .055 �� .07
1074
Legend
F
WS 100 - YR
•
WS 50 - YR
1072
WS 25 - YR
WS 10 - YR
WS 5 YR
•
WS2-YR
1070 -
070WS1-YR
WS 1 -YR
■
Ground
•
Bank Sta
1068-
0681066106410621060
1066-
1064-
1062-
1060-1
0 100
200 300 400 500 600
700
Station (ft)
Appendix B-74

Appendix B-75
BIG CREEK IV Plan: EXISTING 8/19/2016
River = BIG CREEK Reach = REACH 2 RS = 5 XS -16
.07
.055- .04 —= 055 .07
1074
Legend
F
WS 100 - YR
•
WS 50 - YR
1072
�
WS 25 - YR
WS 10 - YR
WS 5 YR
1070
`
WS2-YR
WS1-YR
■
Ground
1068
Bank Sta
1066
w
1064
1062-
06210601058
1060-
1058
0 100
200 300 400 500 600
700
Station (ft)
Appendix B-75

Appendix B-76
BIG CREEK IV Plan: EXISTING 8/19/2016
River = BIG CREEK Reach = REACH 2 RS = 4 XS -17
.07 {>
.055
.04.07�
1078
Legend
F
WS 100 - YR
1076
•
WS 50 - YR
WS 25 - YR
WS 10 - YR
1074
WS 5 - YR
•
WS2-YR
1072
WS 1 -YR
■
Ground
•
Bank Sta
1070-
070106810661064106210601058
1068-
1066-
1064-
1062-
1060-
1058
0 100
200 300 400
500
600
Station (ft)
Appendix B-76

Appendix B-77
BIG CREEK IV Plan: EXISTING 8/19/2016
River = BIG CREEK Reach = REACH 2 RS = 3 XS -18
07
.055 �'
.04 .055 +—.07
1076
Legend
F
WS 100 - YR
•
WS 50 - YR
1074
WS 25 - YR
WS 10 - YR
1072
WS 5 YR
•
WS2-YR
WS1-YR
1070
Ground
•
Bank Sta
1068
0
m
w
1066
1064
1062
10601
1058 T
T T T
T
0 100
200 300 400
500
600
Station (ft)
Appendix B-77

Appendix B-78
BIG CREEK IV
Plan: EXISTING 8/19/2016
River = BIG CREEK
Reach = REACH 2 RS = 2 XS -19
07 055
� 04 055
"4 .07
1076
Legend
F
WS 100 - YR
•
WS 50 - YR
1074
WS 25 - YR
WS 10 - YR
1072
WS 5 - YR
•
WS2-YR
WS1-YR
1070
Ground
•
-
Bank Sta
1068-
068106610641062
1066-
1064-
1062
10601
1058
T T
T T
T
0
100 200
300 400
500 600
Station (ft)
Appendix B-78

Appendix B-79
BIG CREEK IV Plan: EXISTING 8/19/2016
River = BIG CREEK Reach = REACH 2 RS = 1 XS -20
07 '�"
.055 %.04.055--.07�
1080
Legend
WS 100 - YR
•
WS 50 - YR
WS 25 - YR
WS 10 - YR
1075
WS 5 - YR
•
WS2-YR
WS1-YR
■
Ground
•
Bank Sta
1070-
0701065106010550
1065-
1060-
1055-
0100
200 300 400 500 600
700
Station (ft)
Appendix B-79

Appendix B-80
BIG CREEK IV
Plan: EXISTING 8/19/2016
River = BIG CREEK
Reach = REACH 3 RS = 0.5 ADDED XS
07.055
.04
- .055 07
1076
F
Legend
F
WS 100 - YR
1074
•
WS 50 - YR
WS 25 - YR
WS 10 - YR
1072
WS 5 - YR
•
WS2-YR
1070
WS 1 -YR
■
Ground
•
Bank Sta
1068
0
1066 -
LU
1064-
0641062106010581056
1062-
1060-
1058-
10561
-50
0
50 100
150 200 250 300
350
Station (ft)
Appendix B-80

Appendix B-81
BIG CREEK IV
Plan: EXISTING 8/19/2016
River = BIG CREEK
Reach = REACH 3 RS = 0.1 ADDED XS
07.055
.04
- .055 07
1076
F
Legend
F
WS 100 - YR
1074
•
WS 50 - YR
WS 25 - YR
WS 10 - YR
1072
WS 5 - YR
•
WS2-YR
1070
WS 1 -YR
■
Ground
•
Bank Sta
1068
0
.F --
1066 -
LU
1064-
0641062106010581056
1062-
1060-
1058-
1056
-50
0
50 100
150 200 250 300
350
Station (ft)
Appendix B-81

Appendix B-82
BIG CREEK IV Plan: EXISTING 8/19/2016
River = TRIB#1 Reach= EX. THALWEG TRIB RS = 2.1 TRIB #1 XS - 1
.07 .055 "� .04 J, .055 .07
1078
Legend
F
WS 100 - YR
•
WS 50 - YR
1076
WS 25 - YR
WS 10 - YR
WS 5 YR
•
WS2-YR
1074 -
074WS1-YR
WS 1 -YR
■
Ground
•
Bank Sta
1072-
.0
m
w
1070-
0701068106610640
1068-
1066-
1064-
020 40 60 80 100 120 140
160
Station (ft)
Appendix B-82

Appendix B-83
BIG CREEK IV Plan: EXISTING 8/19/2016
River = TRIB#1 Reach= EX. THALWEG TRIB RS = 2 TRIB #1 XS - 1
.07 .055 -.04 " .055 � .07
7
10781
Legend
F
WS 100 - YR
•
WS 50 - YR
1076
WS 25 - YR
WS 10 - YR
WS 5 YR
•
WS2-YR
1074 -
074WS1-YR
WS 1 -YR
■
Ground
•
Bank Sta
1072-
.0
m
w
1070-
0701068106610640
1068-
1066-
1064-
020 40 60 80 100 120 140
160
Station (ft)
Appendix B-83

Appendix B-84
BIG CREEK IV Plan: EXISTING 8/19/2016
River
= TRIB#1 Reach = EX. THALWEG TRIB RS = 1 TRIB #1 XS - 2
07 .055
� .04 - .055
J,—.07
1078
Legend
F
WS 100 - YR
•
WS 50 - YR
1076
�
WS 25 - YR
WS 10 - YR
WS 5 YR
1074
`
WS2-YR
WS1-YR
■
Ground
1072-)
Bank Sta
0
1070-
>
LU
1068-
1066
1064-
1062
0
50
100 150
200
250
Station (ft)
Appendix B-84

Appendix B-85
BIG CREEK IV Plan: EXISTING
8/19/2016
River = TRIB#2 Reach = EX. THALWEG TRIB RS
= 5.1 TRIB #2 XS - 1
.07
.055 J,
.04 x1.055 .07�
1076
Legend
F
WS 100 - YR
•
WS 50 - YR
1074
�
WS 25 - YR
WS 10 - YR
WS 5 YR
1072
`
WS2-YR
WS1-YR
■
Ground
1070
El
Levee
•
-
Bank Sta
0
1068 -
LU
1066
1064-
064106210600
1062-
1060-
0
200 400 600
800
1000
Station (ft)
Appendix B-85

Appendix B-86
BIG CREEK IV Plan: EXISTING 8/19/2016
River = TRIB#2 Reach= EX. THALWEG TRIB RS = 5 TRIB #2 XS - 1
EE 07
055.04 ", .055 .07d
1076
Legend
WS 100 - YR
WS 50 - YR
1074
•
WS 25 - YR
WS 10 - YR
WS5-YR
1072
'
WS2-YR
WS1-YR
■
Ground
1070
Levee
•
Bank Sta
0
1068 -
LU
1066
1064
1062
1060 T
0
200 400 600 800
1000
Station (ft)
Appendix B-86

0
0
m
LU 1
1064
1062-
1060-
1058
06210601058 -
-400
BIG CREEK IV Plan: EXISTING 8/19/2016
River = TRIB#2 Reach = EX. THALWEG TRIB RS = 4 TRIB #2 XS - 2
.07 .055 31( .04 �� .055 .07
-200 0 200 400
Station (ft)
Appendix B-87
F
WS 100 - YR
WS 50 - YR
WS 25 - YR
WS 10 - YR
WS 5 - YR
•
WS2-YR
WS1-YR
■
Ground
E
Levee
•
Bank Sta

Appendix B-88
BIG CREEK IV Plan: EXISTING
8/19/2016
River = TRIB#2 Reach = EX. THALWEG TRIB RS
= 3 TRIB #2 XS - 3
.07 055
055
.07
1076
O
Legend
4
F
WS 100 - YR
•
WS 50 - YR
1074
WS 25 - YR
WS 10 - YR
1072
WS 5 YR
•
WS2-YR
WS1-YR
1070
Ground
•
Bank Sta
1068
0
0
m
LU
1066-
0661064106210601058
1064-
1062-
1060-
1058
-600
-400 -200 0
200
400
600
Station (ft)
Appendix B-88

LU
BIG CREEK IV Plan: EXISTING 8/19/2016
River = TRIB#2 Reach = EX. THALWEG TRIB RS = 2 TRIB #2 XS - 4
.07 .055 d . 9E .055 <L .07
-600 -400 -200 0 200 400
Station (ft)
Appendix B-89
600
F
WS 100 - YR
WS 50 - YR
WS 25 - YR
WS 10 - YR
WS 5 - YR
•
WS2-YR
WS1-YR
■
Ground
E
Levee
•
Bank Sta

1
1
1
1
1
0
0 1
m
LU
1
1
1
1
1
-600 -400 -200 0 200 400 600
BIG CREEK IV Plan: EXISTING 8/19/2016
River = TRIB#2 Reach = EX. THALWEG TRIB RS = 1 TRIB #2 XS - 5
—.07.055 .055 "' 07�
Station (ft)
Appendix B-90
HIM
F
WS 100 - YR
WS 50 - YR
WS 25 - YR
WS 10 - YR
WS 5 - YR
Mrecl►gm�AF
■
Ground
E
Levee
•
Bank Sta

HEC -RAS Plan_ PRBG
River
Reach
River
St. Profile
Q Total
Min Ch EI
W . Elev
Crit W.S.
E.G. Elev
E.G. Slope
Vel Chnl
Flow Area
Top Width
Froude # Chi
Shear Chan
(ofa)
(ft)
(ft)
(ft)
(ft)
(ftRt)
(ft/a)
(aq ft)
(ft)
(Ib/sq ft)
TRIG#2.
PR. THALWEGTRIB
5.1
1 -YR
246.50
1059.65
1062.71
1062.20
1063.19
0.008901
5.57
44.59
24.06
0.68
1.11
TRIB#2
PR. THALWEG TRIB
5.1
2 -YR
491.80
1059.65
1063.85
1063.26
1064.56
0.007605
6.89
79.98
3789
0.67
1.47
TRIB#2
PR. THALWEGTRIB
5.1
5 -YR
976.00
1059.65
1065.97
1064.73
1066.28
0.002437
5.45
360.17
239.91
0.41
0.78
TRIB#2
PR. THALWEG TRIB
5,1
10 -YR
1421.10
1059.65
1067.09
1065.00
1067.25
0.001296
4.51
697.88
355.09
0.31
0.50
TRIB#2
PR. THALWEGTRIB
5.1
25 -YR
2095.30
1059.65
1067.96
1066.26
1068.13
0.001372
5.04
1152.13
731.56
0.33
0.60
TRIB#2
PR. THALWEG TRIB
5.1
50 -YR
2680.40
1059.65
1068.48
1066.81
1068.60
0.001077
4.68
1540.27
764.52
0.29
0.50
TRIB#2
PR. THALWEGTRIB
5.1
100 -YR
3285.10
1059.65
1069.06
1067.08
1069.14
0.000794
4.21
1989.42
782.77
0.26
0.40
TRIB#2
PR. THALWEG TRIB
5
1 -YR
246.50
1059.65
1062.32
1062.20
1063.051
0.016842
6.82
36.13
20.49
0.91
1.77
TRIB#2
PR. THALWEG TRIB
5
2 -YR
491.80
1059.65
1063.53
1063.26
1064.45
0.011202
7.79
68.33
33.87
0.80
1.95
TRIB#2
PR. THALWEGTRIB
5
5 -YR
976.00
1059.65
1065.93
1064.73
1066.25
0.002584
5.58
349.98
237.46
0.43
0.82
TRIB#2
PR. THALWEG TRIB
5
10 -YR
1421.10
1059.65
1067.08
1065.00
1067.24
0.001320
4.54
692.25
353.86
0.31
0.51
TRIM
PR. THALWEGTRIB
5
25 -YR
2095.30
1059.65
1067.95
1066.26
1068.12
0.001398
5.09
1139.78
723.82
0.33
0.61
TRIB#2
PR. THALWEG TRIB
5
50 -YR
2680.40
1059.65
1068.46
1066.81
1068.59
0.001096
4.71
1530.29
764.11
0.30
0.51
TRIB#2
PR. THALWEGTRIB
5
100 -YR
3285.10
1059.65
1069.05
1067.08
1069.14
0.000801
4.23
1982.55
782.50
0.26
0.40
TRIB#2
PR. THALWEGTRIB
4
1 -YR
246.50
1057.37
1061.71
1059.83
1061.93
0.002548
3.71
66.41
20.93
0.37
0.44
TRIB#2
PR. THALWEG TRIB
4
12 -YR
491.801
1057.37
1063.28.
1061.02
1063.61
0.002419
4.72
122.11
55.421
0.38
0.63
TRIB#2
PR. THALWEGTRIB
4
5 -YR
976.00
1057.37
1065.55
1062.871
1065.85
0.001623
5.02
297.51
106.18
0.33
0.62
TRIB#2
PR. THALWEG TRIB
4
10 -YR
1421.10
1057.37
1066.66
1064.24
1067.00
0.001644
5.57
443.43
164.62
0.34
0.73
TRIB#2
PR. THALWEGTRIB
4
25 -YR
2095.30
1057.37
1067.51
1065.27
1067.94
0.001988
6.55
616.79
236.19
0.39
0.98
TRIB#2
PR. THALWEG TRIB
4
50 -YR
2680.40
1057.37
1068.37
1065.95
1068.47
0.000707
4.15
1643.21
639.23
0.23
0.38
TRIB#2
PR. THALWEGTRIB
4
100 -YR
3285.10
1057.37
1068.97
1066.63
1069.05
0.000587
3.93
2029.58
654.47
0.21
0.33
TRIB#2
PR, THALWEGTRIB
3
1 -YR
246.50
1055.38
1061.35
1061.55
0.003047
3.59
68.58
23.26
0.37
0.44
TRIB#2
PR. THALWEG TRIB
3
2 -YR
491.80
1055.38
1063.00
1063.29
0.002764
4.32
116.99
35.98
0.38
0.57
TRIB#2
PR. THALWEGTRIB
3
5 -YR
976.00
1055.38
1065.49
1065.65
0.001067
3.70
546.01
453.51
0.25
0.35
TRIB#2
PR. THALWEG TRIB
3
10 -YR
1421.10
1055.38
1066.781
1066.841
0.000438
1671
1234.301
614.78
0.17
0.17
TRIM
PR. THALWEG TRIB
3
25 -YR
2095.30
1055.38
1067.72
1067.761
0.000361
2.61
1862.39
733.56
0.16
0.16
TRIB#2
PR. THALWEG TRIB
3
50 -YR
2680.40
1055.38
1068.37
1068.40
0.000312
2.55
2357.33
773.80
0.15
0.15
TRIB#2
PR. THALWEGTRIB
3
100 -YR
3285.10
1055.38
1068.96
1068.99
0.000275
2.49
2820.03
787.64
0.14
0.14
TRIB#2
PR. THALWEGTRIB
2
1 -YR
246.50
1054.85
1061.09
1057.95
1061.22
0.001761
2.90
85.10
27.38
0.29
0.28
TRIB#2
PR. THALWEG TRIB
2
2 -YR
491.80
1054.85
1062.79
1059.38
1062.99
0.001601
3.67
144.16
42.86
0.29
0.39
TRIB#2
PR. THALWEGTRIB
2
5 -YR
976.00
1054.85
1065.40
1061.39
1065.51
0.000730
3.30
582.97
394.17
0.21
0.27
TRIB#2
PR. THALWEG TRIB
2
10 -YR
1421.10
1054.85
1066.75
1062.53
1066.79
0.000297
2.35
1565.41
867.46
0.14
0.13
TRIB#2
PR. THALWEGTRIB
2
25 -YR
2095.30
1054.85
1067.70
1063.93
1067.72
0.000208
2.10
2433.93
962.881
0.12
0.10
TRIB#2
PR. THALWEG TRIB
2
50 -YR
2680.40
1054.85
1068.35
1065.62
1068.37
0.000179
2.04
3078.71
1000.411
0.11
0.09
TRIM
PR. THALWEG TRIB
2
100 -YR
3285.10
1054.85
1068.94
1065.95
1068,961
0.000162
2.01
3677.76
1016.62
0.11
0.09
TRIB#2
PR: THALWEGTRIB
1
1 -YR
246.50
1054.99
1061.00
1061.11
0.000851
2.63
96.53
30.04
0.22
0.20
TRIB#2
PR. THALWEG TRIB
1
2 -YR
491.80
1054.99
1062.69
1062.88
0.001037
3.58
161.49
46.92
0.25
0.34
TRIB#2
PR. THALWEGTRIB
1
5 -YR
976.00
1054.99
1065.26
1065.45
0.000819
4.00
537.49
426.15
0.24
0.37
TRIB#2
PR. THALWEG TRIB
1
10 -YR
1421.10
1054.99
1066.70
1066.76
0.000353
2.90
1347.63
703.59
0.16
0.19
TRIB#2
PR. THALWEGTRIB
1
25 -YR
2095.30
1054.99
1067.65
1067.70
0.000291
2.80
2114.82
894.34
0.15
0.17
TRIB#2
PR. THALWEG TRIB
1
50 -YR
2680.401
1054.99
1068.32
1068.35
0.000245
2.67
2738.04
962.39
0.14
0.15
TRIB#2
PR. THALWEGTRIB
1
100 -YR
3285.10
1054.99
1068.92
1068.95
0.000209
2.551
3320.23
976.37
0.13
0.14
TRIB#1
PR. THALWEGTRIB
2.1
1 -YR
5.00
1064.24
1065.15
1064.85
1065.21
0.006316
1.90
2.63
4.64
0.44
0.20
TRIB#1
PR. THALWEG TRIB
2.1
2 -YR
15.90
1064.24
1065.85
1065.33
1065.921
0.004566
2.12
7.50
8.95
0.41
0.22
TRIB#1
PR. THALWEGTRIB
2.1
5 -YR
41.00
1064.24
1067.58
1065.87
1067.61
0.000565
1.39
33.02
26.07
0.17
0.07
TRIB#1
PR. THALWEG TRIB
21
10 -YR
64.80
1064.24
1068.80
1066.22
1068.82
0.000191
1.10
94.43
79.04
0.11
0.04
TRIB#1
PR. THALWEGTRIB
2.1
25 -YR
100.70
1064.24
1069.09
1066.61
1069.11
0.000297
1.44
118.91
92.98
0.13
0.06
TRIB#1
PR. THALWEG TRIB
2.1
50 -YR
129.60
1064,24
1069.55
1066.88
1069.57
0.000245
1.42
167.26
111.87
0.12
0.06
TRIM
PR. THALWEGTRIB
2.1
100 -YR
161.00
1064.24
1070.05
1067.10
1070.07
0.000176
1.30
224.30
112.94
0.11
0.05
TRIB#1
PR, THALWEGTRIB
2
1 -YR
5.00
1064.24
1065.04
1065.13
0.010890
2.341
2.14
4.17
0.57
0.32
TRIB#1
IPR.THALWEG TRIB
2
2 -YR
15.90
1064.24
1065.781
1065.87
0.005656
2.291
6.941
8.67
0.45
0.26
TRIB#1
PR. THALWEG TRIB
2
5 -YR
41.00
1064.24
1067.57
1067.60
0.000571
1.40
32.86
25.91
0.17
0.07
TRIB#1
PR. THALWEG TRIB
2
10 -YR
64.80
1064.24
1068.80
1068.81
0.000192
1.10
94.27
78.95
0.11
0.04
TRIM
PR. THALWEGTRIB
2
25 -YR
100.70
1064.24
1069.08
1069.11
0.000299
1.44
118.64
92.84
0.13
0.06
TRIB#1
PR. THALWEG TRIB
2
50 -YR
129.60
1064.24
1069.54
1069.56
0.000246
1.42
166.98
111.86
0.12
0.06
TRIM
PR. THALWEGTRIB
2
100 -YR
161.00
1064.24
1070.05
1070.07
0.000176
1.30
224.11
112.93
0.11
0.05
TRIB#1
PR. THALWEGTRIB
1
1 -YR
5.00
106347
1064.20
1064.30
0.013823
2.47
2.03
4.48
0.65
0.37
TRIB#1
PR. THALWEG TRIB
1
2 -YR
1 15.90
1063.47
1065.62
1065.64
0.001005
1.24
12.84
11.001
0.20
0.07
TRIB#1
PR. THALWEGTRIB
1
5 -YR
41.00
1063.47
1067.56
1067.57
0.000211
0.91
54.42
59.53
0.10
0.03
TRIB#1
PR. THALWEG TRIB
1
10 -YR
64.80
1063.47
1068.801
1068.80
0.000054
Ml
199.11
170.33
0.06
0.01
TRIB#1
PR. THALWEGTRIB
1
25 -YR
100.70
1063.47
1069.08
1069.09
0.000079
0.78
249.48
182.48
0.07
0.02
TRIB#1
PR. THALWEG TRIB
1
50 -YR
129.60
1063.47
1069.54
1069.55
0.000061
0.73
335.93
188.89
0.06
0.02
TRIB#1
PR. THALWEGTRIB
1
100 -YR
161.00
1063.47
1070.05
1070.06
0.000046
0.68
432.20
190.28
0.05
0.01
BIG CREEK
REACH 1
20.7
1 -YR
191.10
1066.82
1069.61
1068.62
1069.82
0.004054
3.65
52.41
26.30
0.46
0.48
BIG CREEK
REACH
20.7
2 -YR
418.601
1066.82
1071.00
1069.60
1071.27
0.005486
4.15
100.83
42.93
0.48
0.78
BIG CREEK
REACH
20.7
5 -YR
908.20
1066.82
1072.83
1071.07
1072.96
0.002188
3.35
427.27
328.851
0.30
0.50
BIG CREEK
REACH
20.7
10 -YR
1394.90
1066.82
1073.31
1071.93
1073.46
0.002393
3.80
587.67
344.09
0.32
0.62
BIG CREEK
REACH
20.7
25 -YR
2171.40
1066.82
1073.83
1072.95
1074.02
0.002842
4.47
769.53
357.41
0.36
0.82
BIG CREEK
REACH
20.7
50 -YR
2876.90
1066.82
1074.261
1073.23
1074.48
0.002979
4.85
926.86
367.70
0.37
0.94
BIG CREEK
REACH I
20.7
100 -YR
3630.70
1066.82
1074.67
1073.48
1074.91
0.003078
5.18
1079.94
377.44
0.39
1.05
BIG CREEK
REACH 1
20.5
1 -YR
191.10
1066.82
1069.56
1068.62
1069.78
0.004302
3.74
51.05
25.73
0.47
0.51
BIG CREEK
REACH
20.5
2 -YR
418.60
1066.82
1070.93
1069.60
1071.22
0.005810
4.29
97.67
42.05
0.50
0.82
BIG CREEK
REACH
20.5
5 -YR
908.20
1066.82
1072.81
1071.07
1072.94
0.002298
3.42
418.01
327.92
0.31
0.52
BIG CREEK
REACH
20.5
10 -YR
1394.90
1066.82
1073.28
1071.93
1073.43
0.002503
3.86
577.35
343.15
0.33
0.64
BIG CREEK
REACH
20.5
25 -YR
2171.40
1066.82
1073.79
1072.95
1073.99
0.002975
4.55
756.67
356.56
0.37
0.85
BIG CREEK
REACH
20.5
50 -YR
2876.90
1066.82
1074.23
1073.23
1074.45
0.003106
4A21
913.19
366.81
0.38
0.97
BIG CREEK
REACH
20.5
100 -YR
3630.70
1066.82
1074.64
1073.48
1074.88
0.003198
5.26
1065.54
376.53
0.39
1.08
BIG CREEK
REACH 1
20
1 -YR
191.10
1066.35
1068.66
1068.18
1069.00
0.008527
4.70
40.64
24.56
0.64
0.85
BIG CREEK
REACH
20
2 -YR
418.60
1066.35
1070.09
1069.11
1070.54
0.005657
5.32
78.62
28.07
0.56
0.93
BIG CREEK
REACH
20
5 -YR
908.20
1066.35
1071.96
1070.53
1072.64
0.004709
6.70
148.52
50.81
0.55
1.25
BIG CREEK
REACH
20
10 -YR
1394.90
1066.35
1072.92
1071.72
1073.17
0.002105
5.09
580.59
385.78
0.38
0.68
BIG CREEK
REACH
20
25 -YR
2171,40
1066.35
1073.33
1072.91
1073.66
0.002902
6.26
741.55
404.71
0.45
1.00
BIG CREEK
REACHI
20
50 -YR
2876.90
1066.35
1073.79
1073.15
1074.12
0.002873
6.55
931.72
421.98
0.46
1.07
BIG CREEK
REACH
20
100 -YR
3630.70
1066.35
1074.23
1073.47
1074.56
0.002824
6.79
1119.57
436.86
0.46
1.12
BIG CREEK
REACH 1
19
1 -YR
191.10
1063.15
1068.58
1065.40
1068.66
0.001009
2.19
87.12
27:86
0.22
O.t6
BIG CREEK
REACH
19
2 -YR
418.60
1063.15
1070.08
1066.64
1070.24
0.001462
3.19
131.10
30.74
0.27
0.31
BIG CREEK
REACH
19
5 -YR
908.20
1063.151
1072.04
1068.68
1072.33
0.001751
4.47
228.79
58.661
0,321
0.53
Appendix B-91

HEC -RAS Plan: PRSG
Appendix B-92
--------------
---------------
--------------
--------------
--------------
--------------
--------------
---------------
--------------
--------------
--------------
Appendix B-92

HEC -RAS Plan_ PRBG
Appendix B-93
MIMPTIM.M.
M,---------------
---------------
---------------
---------------
---------------
---------------
---------------
---------------
Appendix B-93

Appendix B-94
BIG CREEK IV Plan: PROPOSED 8/19/2016
BIG CREEK REACH 2--�
BIG CREEK REACH 1
1075-11
Legend
WS 100 -YR
WS 50 - YR
■
WS 25 - YR
WS 10 -YR
WS 5 -YR
107011
WS 2 -YR
WS 1 -YR
■
Ground
1065 -
LU
1060
co V Lf) (O
I- W O � � � � �
O O
� � � � � N N
055
1055-
0
0
500
1000 1500 2000 2500
3000 3500
Main Channel Distance (ft)
Appendix B-94

Appendix B-95
BIG CREEK IV Plan: PROPOSED 8/19/2016
TRIB#1 PR. THALWEG TRIB
1071
Legend
WS 100 - YR
WS 50 - YR
1070 _
� � � � g
■
WS 25 - YR
WS 10 -YR
WS 5 -YR
1069
WS 2 -YR
WS 1 -YR
■
Ground
1068
1067 -
LU
1066
1065
1
1064
N N
1063--
063
0
0
20 40 60 80
100
Main Channel Distance (ft)
Appendix B-95

Appendix B-96
BIG CREEK IV Plan: PROPOSED 8/19/2016
TRIB#2 PR. THALWEG TRIB
1070
Legend
WS 100 -YR
WS 50 - YR
1068
0
WS 25 - YR
WS 10 -YR
WS 6 -YR
1066
WS 2 -YR
WS 1 -YR
■
Ground
1064
1062 -
LU
1060-
1058
1056
N M V Lo Ln
1054
T�-
0
100 200 300 400
500
Main Channel Distance (ft)
Appendix B-96

Appendix B-97
BIG CREEK IV Plan: PROPOSED
8/19/2016
River = BIG CREEK Reach = REACH 1 RS =
20.7 ADDED XS
.07
.055
"' 04 —+— .07
1078
Legend
WS 100 - YR
•
WS 50 - YR
WS 25 - YR
1076
WS 10 - YR
WS 5 YR
•
WS2-YR
WS1-YR
1074
Ground
Levee
•
Bank Sta
1072 -
LU
1070-
07010681066
1068-
1066-1
0
100 200 300
400
500
Station (ft)
Appendix B-97

Appendix B-98
BIG CREEK IV Plan: PROPOSED
8/19/2016
River = BIG CREEK Reach = REACH 1 RS =
20.5 ADDED XS
.07
.055
"' 04 —+— .07
1078
Legend
WS 100 - YR
•
WS 50 - YR
WS 25 - YR
1076
WS 10 - YR
WS 5 YR
•
WS2-YR
WS1-YR
1074
Ground
Levee
•
Bank Sta
1072 -
LU
1070-
07010681066
1068-
1066
0
100 200 300
400
500
Station (ft)
Appendix B-98

Appendix B-99
BIG CREEK IV Plan: PROPOSED 8/19/2016
River = BIG CREEK Reach = REACH 1 RS = 20 XS -1
.07
.055
"�' .04 .07
1084
Legend
WS 100 - YR
•
WS 50 - YR
1082
WS 25 - YR
WS 10 - YR
1080
WS 5 YR
•
WS2-YR
WS1-YR
1078
Ground
E
Levee
•
Bank Sta
1076
0
0
m
LU
1074-
0741072107010681066
1072-
1070-
1068-
1066
-100 0
100 200 300
400
500
Station (ft)
Appendix B-99

Appendix B-100
BIG CREEK IV Plan: PROPOSED 8/19/2016
River = BIG CREEK Reach = REACH 1 RS = 19 XS -2
.07
055 2 ' .04 - .055+-.07
1078
Legend
WS 100 - YR
•
WS 50 - YR
1076
�
WS 25 - YR
WS 10 - YR
WS 5 YR
1074
`
WS2-YR
WS1-YR
■
Ground
1072
El
Levee
•
Bank Sta
0
.F --
1070 -
LU
1068
1066-
06610641062
1064-
1062
-200 -100
0 100 200 300 400
500
Station (ft)
Appendix B-100

Appendix B-101
BIG CREEK IV Plan: PROPOSED 8/19/2016
River = BIG CREEK Reach = REACH 1 RS = 18 XS - 3
07
.055 "' .04 �� .055— .07
1078
Legend
F
WS 100 - YR
•
WS 50 - YR
1076
�
WS 25 - YR
WS 10 - YR
WS 5 YR
1074
`
WS2-YR
WS1-YR
■
Ground
1072
Levee
•
Bank Sta
0
.F --
1070 -
LU
1068
1066
1064
1062
0 100
200 300 400 500
600
Station (ft)
Appendix B-101

Appendix B-102
BIG CREEK IV Plan: PROPOSED 8/19/2016
River = BIG CREEK Reach = REACH 1 RS = 17 XS -4
.07 JL.055
"x'.04+-.055 .07�
1078
Legend
F
WS 100 - YR
•
WS 50 - YR
1076
WS 25 - YR
WS 10 - YR
WS 5 YR
•
WS2-YR
1074
WS1-YR
■
Ground
Levee
•
1072
Bank Sta
0
m
LU
1070-
070106810661064
1068-
1066-
1064-1
0 100
200 300 400 500 600
700
Station (ft)
Appendix B-102

Appendix B-103
BIG CREEK IV Plan: PROPOSED 8/19/2016
River = BIG CREEK Reach = REACH 1 RS = 16 XS -5
07
055 "'
.04 .055 .
1078
0
Legend
7
WS 100 - YR
•
WS 50 - YR
1076
�
WS 25 - YR
WS 10 - YR
WS 5 YR
1074
`
WS2-YR
WS1-YR
■
Ground
1072
El
Levee
•
Bank Sta
0
.F --
1070 -
LU
1068
1066
1064
1062
0 100
200 300 400
500
600
Station (ft)
Appendix B-103

Appendix B-104
BIG CREEK IV Plan: PROPOSED 8/19/2016
River = BIG CREEK Reach = REACH 1 RS = 15 XS - 6
.07
.055 ={ .04 �� .055 .07
1080
Legend
WS 100 - YR
•
WS 50 - YR
1078
�
WS 25 - YR
WS 10 - YR
WS 5 YR
1076
`
WS2-YR
WS1-YR
■
Ground
1074
Bank Sta
1072-
0721070106810661064
1070-
1068-
1066-
1064
0 100
200 300 400 500
600
Station (ft)
Appendix B-104

Appendix B-105
BIG CREEK IV Plan: PROPOSED 8/19/2016
River = BIG CREEK Reach = REACH 1 RS = 14 XS -7
.07 �
.055 JL .04 JL .055 -1-.07
1076
Legend
F
WS 100 - YR
•
WS 50 - YR
1074
�
WS 25 - YR
WS 10 - YR
WS 5YR
1072
`
WS2-YR
WS1-YR
■
Ground
1070
Levee
•
Bank Sta
0
.F --
1068 -
LU
1066
1064-
06410621060
1062-
1060
0
100 200 300 400 500
Station (ft)
Appendix B-105

Appendix B-106
BIG CREEK IV Plan: PROPOSED 8/19/2016
River = BIG CREEK Reach = REACH 1 RS = 13 XS -8
07 055 "" .04 .055 J,1076 07
Legend
F
WS 100 - YR
•
WS 50 - YR
1074
WS 25 - YR
WS 10 - YR
WS 5 YR
•
WS2-YR
1072 -
072WS1-YR
WS 1 -YR
■
Ground
E
Levee
•
1070
Bank Sta
0
m
LU
1068-
068106610641062
1066-
1064-
1062-1
0 100 200 300 400 500
600
Station (ft)
Appendix B-106

Appendix B-107
BIG CREEK IV
Plan: PROPOSED
8/19/2016
River = BIG CREEK
Reach = REACH 1 RS
= 12 XS -9
.07 .055
ASA .04 ��
.055 .07
1080
Legend
WS 100 - YR
•
WS 50 - YR
WS 25 - YR
WS 10 - YR
1075
�
WS 5 - YR
•
WS2-YR
WS1-YR
■
Ground
•
Bank Sta
1070-
070106510601055
1065-
1060-
1055
0 100 200
300
400
500
Station (ft)
Appendix B-107

Appendix B-108
BIG CREEK IV Plan: PROPOSED 8/19/2016
River = BIG CREEK Reach = REACH 1 RS = 11 XS -10
07 T .055 .04 1- .055 .07
1080
Legend
WS 100 - YR
•
WS 50 - YR
WS 25 - YR
WS 10 - YR
1075
WS 5 - YR
•
WS2-YR
WS1-YR
■
Ground
•
Bank Sta
1070-
070106510601055
1065-
1060-
1055
0 50 100 150 200 250 300 350
400
Station (ft)
Appendix B-108

Appendix B-109
BIG CREEK IV Plan: PROPOSED 8/19/2016
River = BIG CREEK Reach = REACH 1 RS = 10 XS - 11
.055 .07
07.055 n� .04 IF
1076
Legend
WS 100 - YR
WS 50 - YR
1074
■
WS 25 - YR
WS 10 - YR
WS YR
1072
'
WS2-YR
-
WS1-YR
■
Ground
1070
Levee
Ineff
0
Ban•k Sta
1068 -
LU
1066
1064
1062
1060
0 50 100 150 200 250 300 350
400
Station (ft)
Appendix B-109

Appendix B-110
BIG CREEK IV Plan: PROPOSED 8/19/2016
River = BIG CREEK Reach = REACH 1 RS = 9 XS -12
.07 .055-"I' .04 �� .055 NT
1076
Legend
WS 100 - YR
•
WS 50 - YR
1074
WS 25 - YR
WS 10 - YR
1072
WS 5 YR
•
WS2-YR
WS1-YR
1070
Ground
•
Bank Sta
1068
0
m
w
1066
1064
1062
10601
1058
T T T T
0 100 200 300 400
500
Station (ft)
Appendix B-110

BIG CREEK IV Plan: PROPOSED 8/19/2016
River = BIG CREEK Reach = REACH 1 RS = 8 XS -13
.07 .055 "I' .04+—.055 �� .07
1078
Legend
F
WS 100 - YR
•
1076 WS 50 - YR
WS 25 - YR
WS 10 - YR
1074 WS 5 YR
•
WS2-YR
WS1-YR
1072
Ground
E
Levee
•
Bank Sta
1070-
.0
m
LU 1068-
1066-
1064
06810661064
10621
1060 T T T T Tr
0 100 200 300 400 500 600
Station (ft)
Appendix B-111

Appendix B-112
BIG CREEK IV Plan: PROPOSED 8/19/2016
River = BIG CREEK Reach = REACH 1 RS = 7 XS -14
07 J,.055
31 ".04.055.
1076
0
Legend
7
F
WS 100 - YR
•
WS 50 - YR
1074
�
WS 25 - YR
WS 10 - YR
WS 5 YR
1072
`
WS2-YR
WS1-YR
■
Ground
1070
Levee
•
Bank Sta
0
.F--
1068
LU
1066
1064-
06410621060
1062-
1060
0 100
200 300 400 500
600
700
Station (ft)
Appendix B-112

Appendix B-113
BIG CREEK IV Plan: PROPOSED
8/19/2016
River = BIG CREEK Reach = REACH 2 RS
= 6 XS -15
.07 �
.055
"J'.04 .055 �� .07
1074
Legend
F
WS 100 - YR
•
WS 50 - YR
1072
WS 25 - YR
WS 10 - YR
WS 5 YR
•
WS2-YR
1070 -
070WS1-YR
WS 1 -YR
■
Ground
E
Levee
•
1068
Bank Sta
0
m
w
1066-
066106410621060
1064-
1062-
1060-1
0 100
200 300 400
500 600
700
Station (ft)
Appendix B-113

Appendix B-114
BIG CREEK IV Plan: PROPOSED 8/19/2016
River = BIG CREEK Reach = REACH 2 RS = 5 XS -16
.07
.055 �`- .04 055 .07
1074
Legend
F
WS 100 - YR
•
WS 50 - YR
1072
WS 25 - YR
WS 10 - YR
1070
WS 5 YR
•
WS2-YR
WS1-YR
1068
Ground
E
Levee
•
Bank Sta
1066
0
0
m
LU
1064-
06410621060
1062-
1060
10581
1056 T
T T T T T
r
0 100
200 300 400 500 600
700
Station (ft)
Appendix B-114

Appendix B-115
BIG CREEK IV Plan: PROPOSED
8/19/2016
River = BIG CREEK Reach = REACH 2 RS
= 4 XS -17
07
.055
JE( .04.055 .07
1080
Legend
WS 100 - YR
•
WS 50 - YR
WS 25 - YR
WS 10 - YR
1075
WS 5 - YR
•
WS2-YR
WS1-YR
■
Ground
E
Levee
1070
•
Bank Sta
0
m
LU
1065-
06510601055
1060-
1055
0 100
200 300
400 500
600
Station (ft)
Appendix B-115

Appendix B-116
BIG CREEK IV Plan: PROPOSED
8/19/2016
River = BIG CREEK Reach = REACH 2 RS
= 3 XS -18
07
.055
"I' .04 �� .055 .07
1076
Legend
F
WS 100 - YR
•
WS 50 - YR
1074
WS 25 - YR
WS 10 - YR
1072
WS 5 YR
•
WS2-YR
WS1-YR
1070
Ground
E
Levee
•
Bank Sta
1068
0
0
m
LU
1066-
06610641062
1064-
1062
10601
1058 T
T T
T T
0 100
200 300
400 500
600
Station (ft)
Appendix B-116

Appendix B-117
BIG CREEK IV
Plan: PROPOSED 8/19/2016
River = BIG CREEK
Reach = REACH 2 RS = 2 XS -19
07 31 L5
.055
"' .04 �� .055 .07
1080
T
Legend
WS 100 - YR
•
WS 50 - YR
WS 25 - YR
WS 10 - YR
1075
WS 5 - YR
•
WS2-YR
WS1-YR
■
Ground
•
Bank Sta
1070-
070106510601055
1065-
1060-
1055
0 100
200
300 400 500
600
Station (ft)
Appendix B-117

Appendix B-118
BIG CREEK IV Plan: PROPOSED 8/19/2016
River = BIG CREEK Reach = REACH 2 RS = 1 XS -20
07
.055 7 04 .055 .07
1080
Legend
WS 100 - YR
•
WS 50 - YR
WS 25 - YR
WS 10 - YR
1075
WS 5 - YR
•
WS2-YR
WS1-YR
■
Ground
E
Levee
1070
•
Bank Sta
0
m
LU
1065-
06510601055
1060-
1055
0 100
200 300 400 500 600
700
Station (ft)
Appendix B-118

Appendix B-119
BIG CREEK IV
Plan: PROPOSED 8/19/2016
River = BIG CREEK
Reach = REACH 3 RS = 0.5 ADDED XS
07.055
.04
.055 07
1076
T
Legend
F
WS 100 - YR
1074
•
WS 50 - YR
WS 25 - YR
WS 10 - YR
1072
WS 5 - YR
•
WS2-YR
1070
WS 1 -YR
■
Ground
•
Bank Sta
1068
0
1066 -
LU
1064-
0641062106010581056
1062-
1060-
1058-
10561
-50
0
50 100
150 200 250 300
350
Station (ft)
Appendix B-119

Appendix B-120
BIG CREEK IV Plan: PROPOSED 8/19/2016
River = BIG CREEK Reach = REACH 3 RS = .1 ADDED XS
07
.055 � .04 J
.07
1076
Legend
F
WS 100 - YR
1074
•
WS 50 - YR
WS 25 - YR
WS 10 - YR
1072
WS 5 - YR
•
WS2-YR
1070
WS 1 -YR
■
Ground
•
Bank Sta
1068
0
1066 -
LU
1064-
0641062106010581056
1062-
1060-
1058-
1056
-50
0
50 100 150 200 250
300
350
Station (ft)
Appendix B-120

Appendix B-121
BIG CREEK IV Plan: PROPOSED
8/19/2016
River = TRIB#1 Reach = PR. THALWEG TRIB RS =
2.1 TRIB #1 XS - 1
.07 .055—.04
.05507
1078
Legend
F
WS 100 - YR
•
WS 50 - YR
1076
WS 25 - YR
WS 10 - YR
WS 5 YR
•
WS2-YR
1074 -
074WS1-YR
WS 1 -YR
■
Ground
•
Bank Sta
1072-
.0
m
w
1070-
0701068106610640
1068-
1066-
1064-
020 40 60 80 100
120 140
160
Station (ft)
Appendix B-121

Appendix B-122
BIG CREEK IV
Plan: PROPOSED 8/19/2016
River = TRIB#1 Reach
= PR. THALWEG TRIB RS = 2 TRIB #1 XS - 1
.07 .055—.04
J* .055 � 07
1078
Legend
F
WS 100 - YR
•
WS 50 - YR
1076
WS 25 - YR
WS 10 - YR
WS 5 YR
•
WS2-YR
1074 -
074WS1-YR
WS 1 -YR
■
Ground
•
Bank Sta
1072-
.0
m
w
1070-
0701068106610640
1068-
1066-
1064-
020 40 60
80 100 120 140
160
Station (ft)
Appendix B-122

Appendix B-123
BIG CREEK IV Plan: PROPOSED 8/19/2016
River = TRIB#1 Reach= PR. THALWEG TRIB RS = 1 TRIB #1 XS - 2
07�V 055 04 055 >' .07
1078
Legend
F
WS 100 - YR
•
WS 50 - YR
1076
�
WS 25 - YR
WS 10 - YR
WS 5 YR
1074
`
WS2-YR
WS1-YR
■
Ground
1072-)
Bank Sta
0
070
1070-
LU
w
1068
1066
1064-
1062
0
50 100 150 200
250
Station (ft)
Appendix B-123

Appendix B-124
BIG CREEK IV Plan: PROPOSED 8/19/2016
River = TRIB#2 Reach = PR. THALWEG TRIB RS = 5.1 TRIB #2 XS - 1
.07 .055 .055 .07
1076
0
Legend
4
F
WS 100 - YR
•
WS 50 - YR
1074
WS 25 - YR
WS 10 - YR
1072
WS 5 YR
•
WS2-YR
WS1-YR
1070
Ground
E
Levee
•
Bank Sta
1068
�
0
m
LU
1066-
06610641062
1064-
1062
10601
1058
T T T T
0 200 400 600 800
1000
Station (ft)
Appendix B-124

Appendix B-125
BIG CREEK IV Plan: PROPOSED 8/19/2016
River = TRIB#2 Reach = PR. THALWEG TRIB RS = 5 TRIB #2 XS - 1
.07
.055 J 055 .07
1076
0
Legend
4
F
WS 100 - YR
•
WS 50 - YR
1074
WS 25 - YR
WS 10 - YR
1072
WS 5 YR
•
WS2-YR
WS1-YR
1070
Ground
E
Levee
•
Bank Sta
1068
0
0
m
LU
1066-
06610641062
1064-
1062
10601
1058
T T T T
0
200 400 600 800
1000
Station (ft)
Appendix B-125

LU
BIG CREEK IV Plan: PROPOSED 8/19/2016
River = TRIB#2 Reach = PR. THALWEG TRIB RS = 4 TRIB #2 XS - 2
� .07 .055 .055 > .07 �
-400 -200 0 200 400
Station (ft)
Appendix B-126
F
WS 100 - YR
WS 50 - YR
WS 25 - YR
WS 10 - YR
WS 5 - YR
•
WS2-YR
WS1-YR
■
Ground
E
Levee
•
Bank Sta

Appendix B-127
BIG CREEK IV Plan: PROPOSED 8/19/2016
River = TRIB#2 Reach = PR. THALWEG TRIB
RS = 3 TRIB #2 XS - 3
•07 —"' 055
.055 .07
1075
0
Legend
4
F
WS 100 - YR
•
WS 50 - YR
WS 25 - YR
WS 10 - YR
WS 5 YR
1070
`
WS2-YR
-
WS1-YR
■
Ground
•
Bank Sta
0
.F --
1065 -
LU
1060-
0601055-600
1055-
-600
-400 -200 0
200 400
600
Station (ft)
Appendix B-127

Appendix B-128
BIG CREEK IV Plan: PROPOSED 8/19/2016
River = TRIB#2 Reach = PR. THALWEG TRIB RS = 2 TRIB #2 XS - 4
07
055 "� .055 .07
1072
0 T
Legend
4
F
WS 100 - YR
•
WS 50 - YR
1070
WS 25 - YR
WS 10 - YR
1068
WS 5 YR
•
WS2-YR
WS1-YR
1066
Ground
E
Levee
•
Bank Sta
1064
0
0
m
LU
1062-
0621060105810561054
1060-
1058-
1056-
1054
-600 -400
-200 0 200 400
600
Station (ft)
Appendix B-128

Appendix B-129
BIG CREEK IV Plan: PROPOSED
8/19/2016
River = TRIB#2 Reach = PR. THALWEG TRIB RS
= 1 TRIB #2 XS - 5
.07
.055
.055 .07
1075
0
Legend
4
WS 100 - YR
•
WS 50 - YR
WS 25 - YR
WS 10 - YR
1070
WS 5 - YR
•
WS2-YR
WS1-YR
■
Ground
•
Bank Sta
1065
0
0
m
LU
1060-
06010551050
1055-
1050
-600
-400
-200 0 200
400 600
800
Station (ft)
Appendix B-129

APPENDIX E
Drainage Area Map
Appendix B-130

Drainage Area Characteristics _ .
• Runoff Time • 1 -YR 100 -YR
• • - i` '♦n
Numberzin/SP (Acres)
oy
lee
+31 1
--
ef� �'� 1.
01� lop
lama
AV - f . , ,, tA
lot
• 1 is �,. ;e. �, � •
\ ,.,Legend
Ir Jv-
Study Point
Big Creek IV -B
f
x Big Creek IV -A• sr? r SP01 �. i� 44-4
Tributary #1
i • Creek III"` .• 'i ` i >' d \/ 'lam- •* I
Tributary #2
Jlp
Streams
pp
o'�ywLc oWp=yu uuup.� Dp D�°' �U,�D�I�D�o . Do 0 o 0 0op

APPENDIX F
HEC -RAS Cross Section Map
Appendix B-132

APPENDIX G
00 -Year Floodplain Map
Appendix B-134

GQ�O
J � �
BIG GREEK f
�— TR I BUTAR1' 2
woop
LIMIT OF
STUDY
i
0000
mo
l v
v -•� � � � 'ate ,,,
LIMIT OF
STUDY
�►' B 1 G GREED -01
B 16 GREE<
TRIBUTARY I/