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STATE OF NORTH CAROLINA
DEPARTMENT OF TRANSPORTAT`ION
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, JR.
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 &
011117, 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 hazdwood
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://www.ncdot.or /g doh/preconsh•uct/pe/neu/Monitoring/Monito�-in�Reports.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 corisecutive 34 days. A site visit was
held on April 29`h, 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 1 provides a summary of the hydrologic
MAILING ADDRESS:
NC DEPARTMENT OF TRANSPORTATION
PROJECT DEVELOPMENT AND ENVIRONMENTAL ANALYSIS
1598 MAIL SERVICE CENTER
RALEIGH NC 27699-1598
T E L EPHO N E: 919-707-6000
FAX: 919-212-5785
� WEesire: WWW.NCDOT.ORG
LOCATION:
CENTURY CENTER BUILDING B
1020 BIRCH RIDGE DRIVE
RnlE1GH NC 27610
I
data (the percentage of the growing season that saturation was indicated) at each groundwater
gauge location for the 2006-2008 monitoring years.
Table 1. Summarv of Hvdroloeic
TS-G W 1
TS-GW2
Climate
Conditions
13.2
29.4
Average Rainfall
2006-2008
65.9
100.0
Below Average
Rainfall
100.0
100.0
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. Anrival 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,
� .� ��y
Philip S. Harris, III, P.E., Unit Head
PDEA- Natural Environment Unit
cc: Mr. Brad Shaver, ACO�
Mr. David Wainwright, DWQ
Mr. Travis Wilson, WRC
Mr. Chris Militscher, EPA
Mr. Gary Jordan, USFWS
Mr. Scott McLendon,. AGOE
Mr. Brian Wrenn, DWQ
Mr. David Harris, P.E., NCDOT-REU
Mr. Stoney Mathis, NCDOT-DE03
Mr. Randy Griffin, NCDOT-NEU