20181349 Ver 1_Comment Memo_SAW-2016-01335_20181220

REPLY TO
ATTENTION OF:
CESAW-RG/Browning
DEPARTMENT OF THE ARMY
WILMINGTON DISTRICT, CORPS OF ENGINEERS
69 DARLINGTON AVENUE
WILMINGTON, NORTH CAROLINA 28403-1343
MEMORANDUM FOR RECORD
November 7, 2018
SUBJECT: Mill Dam Creek Site Mitigation Project - 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(8) of the 2008 Mitigation Rule.
NCDMS Project Name: Mill Dam Creek Mitigation Site, Yadkin County, NC
USACE AID#: SAW -2016-01335
NCDMS #: 97136
30 -Day Comment Deadline: November 5, 2018
Mac Haupt, NCD WR:
1. Section 3.1.1- Landscape Characteristics- states in second paragraph that Fairview soils are "
hydric interfluvial soils". The Fairview series is a non -hydric soil (Typic Kanhapludult).
2. DWR believes Section 4.0- Functional Uplift Potential should have mentioned more about the
existing wetlands on site and their potential to be enhanced. For example, it is possible some of
the existing wetlands may be enhanced while other portions of filled relic stream channel may
develop into wetlands, this will be important to show a net positive functional gain to the
wetlands on site for permit purposes.
3. Sect ion 6.4 for Tributary 3 does mention that "the stream restoration will serve to improve
wetland hydrology". DWR would prefer that that a gauge be installed to document this
statement.
4. One negative aspect about this project is the number of crossings (10). In the future, DWR
requests that the number of crossings be minimized.
5. There are several tables that note project reaches with very small drainage areas:
a. Trib T3- 7 acres
b. Trib T4- 3 acres
c. Trib T6A-2- 9 acres
d. Trib 8A- 7acres
Please be aware that the IRT will be paying close attention to the reaches to ensure that the
tributaries maintain an appropriate flow regime. DWR noted that a couple of submitted (DWR)
Stream Forms showed two reaches with low intermittent scores, Tribs 5A and the top of 8A.
KCI may want to consider installing stream gauges in these features.

6. Section 7.0 Performance Standards- states that "project streams must also show a minimum of 30
days of continuous flow..." Please realize this standard was developed initially for coastal
headwater systems. The standard is currently being applied to intermittent streams statewide.
While the IRT is currently reviewing this standard for intermittent streams outside the coastal
plain, the 30 -day flow metric does not apply to perennial streams.
7. The design sheets need to show the location of the jurisdictional wetlands. This will be a
requirement for PCN review. Tributaries with wetlands adjacent are T7, T8, the top of T3 and
UTHC2. In addition, DWR prefers that the stream plan view and profile view appear on the
same page.
8. DWR likes that fact that KCI intends to install a stream gauge on Tributary IA, DWR suggests
the installation occur at stal54+25.
9. DWR likes the fact that this is a large, mostly contiguous (a lot of crossings) project. Moreover,
DWR likes the proposed Regenerative Stormwater Conveyances that are planned to be installed.
Kim Browning, USA CE:
1. Section 4.0: I agree with DWR's comment #2, and would add that while I agree that the wetlands
on-site will likely see a functional uplift, and even though there are no wetland credits being
sought, it is recommended that wetland gauges be installed and monitored in order to demonstrate
no functional loss and/or acreage loss of wetlands with this project, especially for the wetlands
along T7. We cannot authorize impacts, even for restoration, if we are not able to demonstrate that
projects won't impact/degrade existing wetlands (or other aquatic resources) without at least
ensuring that those wetlands will be replaced elsewhere. And the best way to do this is through
groundwater gauges.
a. It might also be beneficial to include the data collection sheets associated with documenting
existing conditions. NC WAM/SAM forms would be beneficial to document existing
conditions, and to compare to in the event that there's a perceived functional loss associated
with the restoration project.
2. USACE agrees that 10 culverts and two utility crossings seems excessive for this project,
especially the culvert on reach T8 where such a small sections of stream is planned for restoration
before the easement ends.
3. Section 7.0: Table 4 indicates that both C and B channels are proposed for this project. If that's
the case, please update the Stream Geomorphology Performance standard to include "The
Entrenchment Ratio (ER) shall be no less than 1.4 for all measured riffle cross-sections on a given
reach (for B channels)."
4. Please include the location of existing wetlands on the Plan Sheets.
5. Section 6.7: Please include a description of the planned pond dam removal, as well as the
proposed pond bed sediment removal.
6. Section 8.0: Vegetation MonitoringVeg plots should be added to the areas with existing
wetlands, particularly along T7 and in the area where the pond bed currently is.
BROWN I N G .KIMBERLY. BROWINIsigned by
NG.KIMBERLY.DANIELLE.1527683510
DN: c=US, o=U.S. Government, ou=DoD, ou=PKI, ou=USA,
DAN I ELLE.1527683510 Date: 20 8.1N061n553:32 05'00'LLE.1527683510
Kim Browning
Mitigation Specialist
Regulatory Division