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Home My WebLink About20091190 Ver 1_Mitigation Bank Proposal Review_20091002NCDENR North Carolina Department of Environment and Natural Resources Division of Water Quality Beverly Eaves Perdue Coleen H. Sullins Dee Freeman Governor Director Secretary October 12, 2009 Mecklenburg County Mr. Stephen Chapin U.S. Army Corps of Engineers Asheville Regulatory Field Office 151 Patton Avenue, Room 208 Asheville, NC 28801-5006 Q 9- 1 1 9 O 9- 1 1 9 0 JJk+Gt,. CL Subject Project: Catawba River Umbrella Mitigation Bank, McDowell Creek Tributary Site Prospectus review Dear Mr. Chapin: The Division of Water Quality (DWQ) 401 Oversight and Express Review Permitting Unit has reviewed the Prospectus (dated August 31, 2009) for the above-referenced umbrella mitigation bank and initial bank project. At your request, our comments are as follows: • Overall, the mitigation bank appears to be well-positioned, and the initial project appears to be a viable candidate for providing mitigation credits through the restoration and enhancement of a stream network and associated wetlands and riparian buffer. We support the-furtiher-development-of ari Umbrella Mitigation-Banking-Instrument for the bank and a mitigation plan for the McDowell Creek Tributary Bank Site. The UMBI should clarify the Conditions. on Debiting and define a "credit" for the purposes of this bank. Generally, 2 acres of wetland restoration (or 1 acre of restoration and 1 restoration equivalent composed of preservation or enhancement with ratios applied) will be debited for every acre of wetland impact. Stream mitigation requirements will be determined according to the 2003 (or subsequent) Stream Mitigation Guidelines and the permitting agencies. The credit release schedule for wetlands should be modified slightly to show 10% of credits released after demonstration of success in each of the seven monitoring years. Wetland monitoring should occur for seven years. If hydrology success has been demonstrated during the first five years, the IRT may consider allowing the sponsor to discontinue groundwater monitoring and continue vegetation monitoring only during the last two years of the monitoring period. • The credit release schedule for streams should include the following events. Each credit release is dependent upon approval from the USACE after consultation with the IRT. 401 Oversight/Express Review Permitting Unit One 1650 Mail Service Center, Raleigh, North Carolina 27699-1650 NorthCarolina Location: 2321 Crabtree Blvd., Raleigh, North Carolina 27604 ;V7 Phone: 919-733-17861 FAX: 919-733-6893 aturall? Internett fittpa/h26.e6r state.nc.is/r cw tlands/ An Equal Opportunity 1 Affirmative Action Employer Catawba River Umbrella Mitigation Bank & McDowell Creek Bank Site Page 2 of 3 o 15% upon completion of execution of the mitigation banking instrument by the sponsor and the IRT, approval of the mitigation plan, delivery of financial assurances, and recordation of the preservation mechanism and title opinion covering the property. o 15% upon completion of all initial physical and biological improvements made pursuant to the mitigation plan. o 10% after each of monitoring years one through four, provided the channel is stable and all other success criteria are met. o 15% after monitoring year five, provided the channel is stable and all other success criteria are met. o 15% anytime after two bank-full events have occurred, in separate years, provided the channel remains stable and all other success criteria are met. In the event that less than two bank-full events occur during the monitoring period, the remaining credit release shall be at the discretion of the IRT. In regards to Contingency Plans and Corrective Actions, the bank sponsor shall be responsible for all corrective actions necessary,to maintain the integrity of the mitigation project until its transfer to the long-term land steward, regardless of the cause of deficient conditions. Our rules (15A NCAC 21-1 .0506 (h)(8)) indicate that mitigation shall occur within the same river basin and physiographic province when practical. Current State law (SL 2009-337) requires non-governmental permittees to utilize mitigation bank credits if they are available within the same 8-digit Cataloging Unit as the impact. The Geographic Service Area (GSA) should include the area inYwhich the mitigation site can reasonably be expected to offset the loss of water quality due to impacts of similar wetland resources. The location of the proposed McDowell Creek Bank Site involves an 8-digit CU that spans both the Piedmont and Blue Ridge Mountains Level 3 Omernik ecoregions. We suggest that the primary GSA of the proposed project be limited to the portion of the 8-digit hydrologic unit within the Piedmont ecoregion, and that any use in adjacent cataloging units within the Catawba Basin be subject to the ratio adjustments specified in Guidance on the Use of Compensatory Mitigation in Adjacent Cataloging Units (available at http://h2o.enr. state.nc.us/ncwetlands/documents/PACGconcurrenceonAdj CU.doc). • We appreciate the efforts taken to consult several watershed plans and articles in order to consider the project in a watershed context. The proposal describes how current and expected urbanization around the McDowell Site will be taken into account when designing the project for long-term stability and viability. • The conceptual restoration plan does not specify the extent of the conservation easement boundaries. The conservation easement perimeter fencing should be far enough from the restored stream reaches to provide a minimum 50-foot undisturbed (i.e. not impacted by herbicide application or mowing for fence rnaihtenance) riparian buffer in all locations. Catawba River Umbrella Mitigation Bank & McDowell Creek Bank Site Page 3 of 3 The conceptual restoration plan indicates that the restored wetland type will be a seasonally saturated forested wetland'with a minimum hydroperiod of 5 percent of the growing season. As you know, Table 5 in the 1987 Corps of Engineers Wetlands Delineation Manual describes "seasonally inundated or saturated" as 12.5 to 25 percent of the growing season. We recommend that the bank sponsor aim for greater than the minimum jurisdictional hydroperiod in the restored wetlands. Targeted hydroperiods should be developed based upon hydrologic modeling, reference comparisons, and community descriptions available in the scientific literature. In the absence of data indicating that the site should be drier; 12.5% in most years is a reasonable target for bottomland hardwood forest restoration projects, especially during the early years of site development when evapotranspiration is low. We appreciate the opportunity to comment on the Mitigation Prospectus. If the bank and initial project move forward, we will look forward to reviewing a more detailed mitigation banking instrument and McDowell Creek Site mitigation plan, and visiting the site with the IRT and bank sponsor at some point in the future. Please feel free to contact Eric Kulz or Tammy Hill at (919) 733-1786 regarding our comments or any issues related to this bank. Sincerely, - d r6L,-4 Cyndi B. Karoly, Program Manager 401 Oversight and Express Review Program Cc: Mr. Alan Johnson, DWQ Mooresville Regional Office Ms. Becky Fox, US EPA, 1307 Firefly Road, Whittier, NC 28789 Mr. Brian Tompkins, US FWS, 160 Zillicoa.Street, Asheville, NC 28801 Mr. Ron Linville, NC WRC, 3855 Idlewild Road, Kernersville, NC 27284-9180