20130411 Ver 1_Staff Comments_20130522

Strickland, Bev
From: Kulz, Eric
Sent: Wednesday, May 22, 2013 2:04 PM
To: and rew .e.wiIIiams2 @usace. army. mi1; Matthews, Monte K SAW
( Monte .K.Matthews @usace. army. mi1)
Cc: Homewood, Sue; Strickland, Bev
Subject: DWQ Comments on Lower Swepsonville Mitigation Bank - Alamance County ( #13 -0411)
DWQ Comments — Lower Swepsonville Dam Mitigation Bank
• Due to the presence of dams both upstream and downstream from the proposed mitigation bank reach, and the
water quality within the Haw River and Little Alamance Creek due to upstream land use, the potential for
improvement of aquatic function appears limited. Of particular concern is the dam immediately upstream from
the proposed bank reach (Upper Swepsonville Dam). During the presentation it was noted that this dam may be
removed by American Rivers. If this dam is not removed, the viability of this site to generate compensatory
mitigation is in question.
• If the proposed bank is to move forward, monitoring needs to be designed to demonstrate uplift, such as
o Improvement of water quality /303d issues could be demonstrate by conducting Chlorophyll a sampling
and macrobenthos sampling and biotic index /bioclassification calculation. Ambient water quality in the
Haw River may limit significant improvement of the benthic community which would indicate an
improvement of aquatic function.
o Restoration of natural flow regime (lentic to lotic system) could be demonstrated through
macrobenthos, mussel and fish surveys, with the same potential limitations as described above.
• Lack of protection /control over the riparian areas is a concern. Unlike the proposed Hoosier Dam project,
protection of riparian buffers on the main stem and tributaries of the proposed bank are less likely, which may
reduce the viability of the site as a mitigation bank, when added to other issues of concern.
• 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, which would negatively affect the aquatic function and
potential uplift in these tributaries. Separate goals and monitoring protocols may be warranted on the
tributaries.
• Research must be done into whether there will be any effect on the Burlington WWTP outfall or or permitted
discharge volumes.
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 —The watershed upstream of the Lower Swepsonville Dam includes a number of historical and current
industrial facilities and developed areas. Sediment quantity, and particularly quality, are concerns. Assessment
of sediment is necessary to determine if contaminated sediments are present. Depending on the results of the
assessment(s), a sediment management plan, and possibly sediment removal, may be necessary.
• Evaluation of the upstream watershed should be conducted for potential impacts to wetlands that may be
altered /drained by the dam removal and subsequent lowering of the water level.

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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