20130412 Ver 1_Staff Comments_20130522 (2)

Strickland, Bev
From: Kulz, Eric
Sent: Wednesday, May 22, 2013 1:13 PM
To: Matthews, Monte; and rew .e.wiIIiams2 @usace. army. miI
Cc: Homewood, Sue; Strickland, Bev
Subject: DWQ Comments on Proposed Hoosier Dam Mitigation Bank - Chatham County ( #13 -0412)
Monte:
Please see our comments below:
DWQ Comments — Hoosier Dam Mitigation Bank
Due to the presence of critical habitat upstream and downstream for T &E species, the location appears
favorable for a mitigation bank. The potential for improvement of aquatic function is likely. However,
monitoring needs to be designed to demonstrate uplift, such as
• Recolonization by Cape Fear Shiner and /or other species using same habitat could be demonstrated by
performing pre and post removal fish surveys.
• Improvement of water quality /303d issues could be demonstrated by conducting pre and post - removal
Chlorophyll a sampling, macrobenthos sampling and biotic index /bioclassification calculation.
• Restoration of natural flow regime (lentic to lotic system) could be demonstrated through pre and post -
removal macrobenthos, mussel and fish surveys.
DWQ acknowledges the fact that some riparian buffers will be placed within conservation easements, and we
feel that this enhances the viability of this project as a mitigation bank. We have a particular interest in
establishing and protecting riparian buffers along the tributaries, as the buffers have a greater positive effect on
water quality than on the main stem due to the ability to create a closed canopy, which provides
shading /temperature moderation, organic matter, and large woody debris.
• The tributaries are a concern. Intermittent vs perennial determinations should be performed. Uplift in
tributaries needs to be demonstrated (see above). There is the possibility of downcutting based on observations
along the former Carbonton Dam impounded reach.
Crediting — generation of credit should be tied to demonstration of project goals and objectives (improvement
of aquatic function), examples of which were provided above. Of particular concern is crediting on the
tributaries, which may not show the amount of uplift expected in the main stem. Crediting should also reflect
the amount of protected buffer along the main stem and tributaries, particularly in light of the potential for the
repeal of the Jordan Lake Buffer Rule.
• Sediment — While the watershed upstream of the Hoosier Dam appears to be mostly undeveloped, sediment
quantity and quality is a concern. Assessment of sediment is recommended (at least Tier 1). A sediment
management plan will likely be necessary to protect critical habitat downstream.
Service area —The requested service area includes the HUC in which the proposed bank is located (03030003),
plus the next downstream HUC (03030004). In the past the IRT has approved multiple HUCs for several banks
(Stone Farm, Barra Farm, Hoffmann). However, given recent legislation requiring the use of banks before
accessing EEP, adding a second eight -digit HUC could confuse the hierarchy requirements (e.g. for an impact in
03030004, does the bank, located within 03030003 with a service area including 03030004 get precedence over
an EEP site in 03030004 ?).

DWQ does acknowledge the location of the proposed mitigation site near the downstream end of 03030003. If
it is decided that the service area can include both 03030003 and 03030004, DWQ recommends the following
exceptions be considered for discussion:
1. The Randleman portion of 03030003 be excluded from the service area.
2. The Coastal Plain portion of 03030004 be excluded (mitigation in Piedmont ecoregion only).
DWQ reserves the right to provide additional comments on the final prospectus, mitigation plan, and /or 401 WQC
application.
Eric W. Kulz
Environmental Senior Specialist
N.C. Division of Water Quality
Wetlands, Buffers, Stormwater - Compliance & Permitting Unit
1650 MSC
Raleigh, NC 27699 -1650
Phone: [phone]
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