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Home My WebLink About20001045_Mitigation Information_20110805STATE OF NORTH CAROLINA DEPARTMENT OF TRANSPORTATION BEVERLY EAVES PERDUE GOVERNOR August 5 2011 Mr Doug Huggett NC Division of Coastal Management Parker Lincoln Building 2728 Capital Boulevard Raleigh NC 27604 EUGENE A CONTI 1R SECRETARY Re Third Street Bridge Mitigation Site New Hanover County State Project No 8 2250110 TIP No U 0092A Action ID No 199603836 DWQ WQC Project No 001045 & 01 1117 DCM Permit No 178 00 Mr Huggett As you are aware the Department has monitored the Third Street Bridge Mitigation Site since its construction in Spring of 2006 Located in New Hanover County adjacent to the Smith Creek Parkway this 1 30 acre site was monitored to provide compensation for unavoidable wetland impacts associated with the U 0092A Smith Creek Parkway project The wetland creation area was graded to the elevation of the adjacent wetland and planted with bottomland hardwood species Two groundwater monitoring gauges and a surface water tidal gauge were installed to record the hydrologic data at the site in May of 2006 According to permit conditions NCDOT was required to monitor the Third Street Bridge Mitigation Site for five years or until success criteria were met with vegetation and hydrologic monitoring conducted each year After each growing season annual monitoring reports were submitted to the appropriate regulatory agencies via the Natural Environment Unit s (NEU) website http / /wn,w ncdot ot R doh/ preconstruct /pe/ncu/Monitorrn_ /Monitoi ingReports html Hydrologic success criteria for the site states that the wetland restoration area must be inundated or saturated (within 12 inches of the surface) by surface or groundwater for at least a consecutive 12 5% of the growing season during years of normal rainfall Therefore for the 273 day growing season in New Hanover County the 12 5% criterion is a consecutive 34 days A site visit was held on April 291h 2009 with the regulatory agencies to address problems with the planted shrub vegetation and the success of the hydrologic monitoring Based on that meeting it was agreed that NCDOT would continue vegetation monitoring through the five year monitoring period but hydrologic monitoring could be discontinued Table I provides a summary of the hydrologic MAILING ADDRESS TELEPHONE 919 707 6000 LOCATION NC DEPARTMENT OF TRANSPORTATION FAX 919 212 5785 CENTURY CENTER BUILDING B PROJECT DEVELOPMENT AND ENVIRONMENTAL ANALYSIS 1020 BIRCH RIDGE DRIVE 1598 MAIL SERVICE CENTER WEBsiTE WWW NCDOT ORG RALEIGH NC 27610 RALEIGH NC 27699 1598 data (the percentage of the growing season that saturation was indicated) at each groundwater gauge location for the 2006 2008 monitoring years Table 1 Summary of Hvdroloeic Monitormia Data 2006 -2008 Monitoring Gauge 2006 Results 2007 Results 2008 Results TS GW1 13 2 65 9 1000 TS GW2 294 1000 1000 Climate Conditions Average Rainfall Below Average Rainfall Average Rainfall After five years of vegetation monitoring vegetation data for 2010 shows that the site has not met the vegetative success criteria by yielding an average density of 248 trees per acre which is below the minimum success criteria of 260 trees per acre The shrub area located under the bridges has continued to fail to meet the vegetation success criteria due to soil compaction issues This 0 47 acre area has been addressed with the regulatory agencies and due to the significant amount of mitigation that was provided for the U 0092 projects it has been determined that no additional mitigation will be required Annual monitoring data is provided within the annual monitoring reports submitted between 2004 and 2008 NCDOT has completed the monitoring requirements as stated in the permit for U 0092A and requests that the Third Street Bridge site is closed NCDOT requests that the appropriate resource agencies provide documentation stating that no further monitoring is required If you have any questions about this project please contact Mr Randy Griffin at (919) 707 6121 Sincerely Philip S Harris III P E Unit Head PDEA Natural Environment Unit cc Mr Brad Shaver ACOE Mr David Wainwright DWQ Mr Travis Wilson WRC Mr Chris Militscher EPA Mr Gary Jordan USFWS Mr Scott McLendon ACOE Mr Brian Wrenn DWQ Mr David Harris P E NCDOT REU Mr Stoney Mathis NCDOT DE03 Mr Randy Griffin NCDOT NEU