20140334 Ver 1_Draft MP Comment Memo_SAW-2015-01209_20151125 (2)

DEPARTMENT OF THE ARMY
WILMINGTON DISTRICT, CORPS OF ENGINEERS
69 DARLINGTON AVENUE
WILMINGTON, NORTH CAROLINA 28403-1343

REPLY TO
ATTENTION OF:

CESAW-RG/Hughes November 25, 2015

MEMORANDUM FOR RECORD

SUBJECT: Candy Creek Mitigation Site - NCIRT Comments During 30-day Mitigation Plan
Review

PURPOSE: The comments listed below were posted to the NCDMS Mitigation Plan Review
Portal during the 30-day comment period in accordance with Section 332.8(g) of the 2008
Mitigation Rule.

NCDMS Project Name: Candy Creek Mitigation Site, Guilford County, NC

USACE AID#: SAW-2015-01209
NCDMS #: 96315

30-Day Comment Deadline: 29 October, 2015

Mac Haupt, Ginny Baker, Sue Homewood, NCDWR, 29 October, 2015:
1. DWR likes the fact that this project represents a true watershed/catchment project,
“…the site will treat almost all of the headwaters of Candy Creek and 47% of the entire
3.1 square mile watershed before it flows into the Haw River…”
2. While DWR appreciates the watershed approach of the Candy Creek project a
considerable amount of work (grading, channel construction) will occur in the upper
reaches where a mature riparian buffer exists. While on a site visit, October 20th,
Wildlands sited their experience of building stream restoration projects through a
mature riparian buffer, Little Troublesome and Agony Acres. DWR cannot stress enough
the importance of minimizing the impact to the existing vegetation during the
construction of the project.
3. The discussion of existing vegetation specifics is fairly sparse in the Mitigation Plan.
DWR suggests going into more specifics in describing what trees are present. DWR
recommends going into specifics regarding the mature trees in Reaches 1A, 1B and 1C
since a lot of those species will be subject to the channel and floodplain construction.
These reaches can be the examples for all the reaches that predominantly contain a
mature wooded buffer. Moreover, the existing mature canopy and shaded conditions
would provide a good opportunity to incorporate planting some shade tolerant shrubs
in addition to the proposed species list with the understanding of the IRT that height
requirements would not be applicable for these shrubs. DWR also wondering whether
any planting was planned of herbaceous species in the vernal pools created from filled
channels.
4. The areas of floodplain cut that the Mitigation Plan mentions along two specific reaches
(portions of Reach 1 and 2) were initially a concern, however, after another walk
through of the site on October 20th, DWR representatives believe that these transition
areas are justified and care will be taken to tie these cut areas into existing lower areas
of the floodplain.
5. DWR noted in the Mitigation Plan and in the field visits the many wetland pockets that
the Candy Creek project contains. While many of the wetlands on site are degraded,
care should be taken to minimize the impact of jurisdictional wetlands. DWR does
recognize that much of the stream work should enhance most of the wetland hydrology
although a few wetlands will be permanently impacted from the stream channel work.
6. DWR recommends the removal of noted (in the Mitigation Plan and site visits) exotic
vegetation where practicable.
7. Reach UT1C: The Mitigation Plan states Wildlands will be draining the pond but no
details were offered. For example,
a. What is the proposed construction sequence?
b. What is the existing sediment level in the pond bottom?
c. Will they will excavate sediment or will the stream be constructed within the
sediment?
While this was brought up as a question/concern in the 2014 IRT site visit for the pond
on UT2, and the Mitigation Plan addresses these questions for the UT2 pond, the
Mitigation Plan does not address any of these questions for this pond.
8. The Mitigation Plan states that material from the excavated pond will be used to build
up stream UT1C. DWR has reservations about using sediment from the bottom of a
pond to create stable channel fill.
9. The Mitigation Plan calls the design of UT1C to be a step-pool system but there appears
to be a lot of meander for a step-pool system. In addition, the grade appears to be held
by constructed riffles and if the area adjacent to the channel is unconsolidated
sediments (if they aren’t proposing to remove all sediment) then DWR believes the
constructed riffles may not be sufficient to keep the channel in place.
10. Regarding UT2 Reach 1A, during the site visit on October 20th, discussions were held
concerning the best approach. Specifically, the planned approach was to cut a bench on
this small incised reach versus utilizing a modified in-stream structure approach to
promote stability and to partially fill the incised channel to raise the stream bed. DWR
recommends that Wildlands consider an alternative approach on this reach. If Wildlands
pursues this change, the final mitigation plan should provide an explanation as to how
the structure will be monitored to ensure the restored channel maintains at least
intermittent flow. In the event that intermittent flow is discontinued (e.g. conversion to
an ephemeral, non-jurisdictional channel), the length of channel in which no flow is
occurring shall be considered a permanent stream impact and mitigation may be
required to compensate for the lost aquatic function.
11. Regarding UT2, UT2A, and UT2B, DWR noted the extensive use of log sills in the
preliminary plans for these reaches. While DWR likes the purpose of log sills, we have
noticed failure to hold grade in other projects, especially when utilized in areas of higher
slope. DWR recommends careful supervision when these structures are installed.
12. Regarding Reach 1A, DWR suggests that another cross-section be added along Reach 1A
between the two vegetation plots. DWR recalls this section as highly incised and clearly
very erodible.
13. Regarding Reach 4B, Table 14b, Design Morphological Parameters, lists the range for the
Meander Width Ratio (MWR) of Reach 4B to have a range of 1.5 to 5. Typically most
stream restoration projects, particularly in streams with a 3 mi2 drainage area, have a
MWR of 3. Please explain the reasoning for the lower end of range being 1.5.

Andrea Hughes, USACE, 23 November, 2015:
1. Please include the proposed plant list chart(s) in the text document.
2. All intermittent stream channels proposed for restoration should document a minimum
30 days of continuous flow on an annual basis.
3. Under Vegetation Performance Standards on page 54, the draft plan indicates that if
planted stems are at least 260 per acre, monitoring of the vegetation on the site may be
terminated. Please note that requirements for early termination of monitoring also
include vigor, and Years 1-5 monitoring should demonstrate no invasive species issues.
4. Regarding the conservation easement (CE) in Appendix 1, please address the issues
below:
a. Should the CE template be revised to show that DENR is now DEQ?
b. Page 5, Section L, Water Quality and Drainage Patterns, indicates water may be
temporarily withdrawn for good cause shown as needed for the survival of
livestock on the Property. This should require approval by the conservation
easement holder and pumps should be placed outside the easement boundary
with temporary placement of pipes for withdrawal.
c. Page 5, Section O, Disturbance of Natural Features, indicates the Grantor may
request permission to vary from the CE restrictions for good cause shown. The
intent of this paragraph is to allow for activities that will benefit the ecological
functions on the mitigation site and supports the objectives of the mitigation
plan. Please revise this section to clarify the intent of this paragraph.
d. The survey plat indicates a 20 ft utility line crossing Candy Creek in two locations;
a 10 ft utility crossing in the buffer; and a drainage maintenance and utility
easement that extends 50 feet from top of bank (on both sides). The mitigation
plan did not include any information regarding these easements. Please provide
additional information for these areas including the intent for placement of an
easement for each area (future utility line, etc.), the holder for each easement
area (utility company, county, municipality, etc.) and how these easements will
be addressed to ensure project success and sustainability.
e. The survey plat indicates a reserved crossing of Reach 3 above its confluence
with UT 1C. This crossing should be shown on Figure 10 a (concept design map)
and details provided in the text document.
f. The survey plat indicates a reserved crossing of UT 2 just below Reach 1 and
before the confluence with UT 2B. This crossing should be shown on Figure 10 a
(concept design map) and details provided in the text document.
g. The survey plat indicates a reserved crossing of UT 5 just before the confluence
with Candy Creek. This crossing should be shown on Figure 10 a (concept design
map) and details provided in the text document.

Andrea Hughes
Mitigation Project Manager
Regulatory Division
HUGHES.ANDREA.
WADE.1258339165
Digitally signed by
HUGHES.ANDREA.WADE.1258339165
DN: c=US, o=U.S. Government, ou=DoD,
ou=PKI, ou=USA,
cn=HUGHES.ANDREA.WADE.1258339165
Date: 2015.11.25 13:41:28 -05'00'