20001024 Ver 1_Monitoring Report Review_20070411

NC Division of Water Quality
401 Oversight and Express Permitting Unit
April 11, 2007
Memorandum
To: File - DWQ # 20001024
From: Tammy Hill
Subject: Comments on Monitoring Report, Year 5 (final - requesting release) - Bear Creek-
Mill Branch Wetland Mitigation Bank
Report prepared by Restoration Systems, LLC
1) Background
a) Lenoir County
b) 445 acres riverine floodplain, inner Coastal Plain, Neuse basin:
i) 303 acres = wetland areas within regional wildlife corridors to the Neuse River
ii) 145 acres = the Core Restoration Area, adjacent to Bear Creek & Mill Branch;
restored ag land
c) Credit goals:
i) 88 ac WL restoration
ii) 34 ac WL enhancement
iii) 303 ac WL preservation
d) Associated impact: bank designed for use by DOT
e) Mitigation history:
i) Mitigation plan & MBRT: 1999
ii) Construction & veg planting: fall 2001-winter 2002
iii) As-built: January 2002
f) Monitoring
i) Reference ecosystems used extensively in success evaluation
ii) 10 quadrants: 6 bottomland HW on floodplain flats adjacent to Bear Creek, 4
cypress-tupelo swamp forest quads within backwater slough areas along periphery &
inundated portions of floodplain
iii) Figure 2 - even distribution of monitoring stations across site
2) Hydrology
a) 10 gauges + 2 in reference, continuous
b) Success criteria: minimum regulatory criteria or comparison with reference
i) Bottomland hardwood: saturation or inundation for minimum consecutive 5% of GS
ii) Swamp forest: saturation or inundation for minimum consecutive 12.5% of GS
iii) In drought years, hydroperiod must exceed 75% that of reference
c) 2006 data: all gauges exceeded 12.5%
i) max consecutive saturated days: 167 - 249 (most at 249 = 100% of GS); 86 days in
reference bottomland, 249 days in reference swamp
North Carolina Division of Water Quality; 401 Oversight and Express Permitting Unit
1650 Mail Service Center; Raleigh, NC 27699-1650
2321 Crabtree Blvd., Raleigh, NC 27604-2260
Telephone: [phone]; Fax: [phone]
http://ncwaterquality.org/wetlands
111C
NC Division of Water Quality
401 Oversight and Express Permitting Unit
ii) only 2 gauges indicated standing water for the entire GS (SF4, SF5 - both had at
least 4" of water all year), but others showed inundation over the majority of the GS
(BI-13, 131-14, 131-15, SF2)
iii) There is data for SF5, but its location is not noted on map (?)
3) Vegetation
a) 10 2-transect plots (0.11 acre each)
b) Recorded: tree species, counts, and height
c) Reported: combined data for average density, by species
d) Success criteria
i) Separate criteria for the 2 ecosystem types
ii) BH forest (typically high diversity): Minimum mean density of 320 characteristic tree
species/acre at 3 years, 290 at 4, 260 at year 5; at least 5 species, no species > 20%
of stem/acre total
iii) Riverine backwater swamp (typically low density & diversity): Minimum mean density
of 320 characteristic tree species/acre at 3 years, 290 at 4, 260 at year 5; 1 species
(most likely bald cypress, water tupelo, and/or swamp tupelo) may represent up to
100% of stem/acre total; volunteers may be up to 20% of required stem/acre total
e) 2006 results
i) Density & diversity met by characteristic species in all plots
ii) % of total for each species was not reported - at a glance, it appears that the only
BHF species exceeding 20% is swamp tupelo at - 33%
iii) Red maple not counted toward success - it is vastly dominant within the BHF areas
(2142 stems/acre!)
iv) Chinese privet recorded in plots 131-15, 131-16, SF1, AND SF4, but reducing in quantity
since previous years
4) Photos
a) Most show maturing woody veg - not as obvious in 131-12 & 131-14
b) No photo (or veg data) for SF5 ??\\
Additional Issues & Questions:
1) DWQ to do
a) Contact Dave Lekson about schedule for site visit to decide about release of site.
b) Confirm that SF5 is not on map - if not, request revision with its location.
2) For Letter
a) The majority of gauges in both ecosystem types were saturated for the entire growing
season, and SF4 and SF5 were inundated with at least 4 inches of water all year.
b) Regarding veg diversity: Do we want them to revise Table 4 to include % of each
species?? Do we grant full credit even though swamp tupelo exceeded 20% of total in
BHF? See note above regarding red maple dominance - do we grant full credit in spite
of red maple prevalence?
3) For site visit
a) Look at prevalence of inundation & impact on veg growth throughout site
b) Look at impact of Chinese privet, red maple
North Carolina Division of Water Quality; 401 Oversight and Express Permitting Unit
1650 Mail Service Center; Raleigh, NC 27699-1650
2321 Crabtree Blvd., Raleigh, NC 27604-2260
Telephone: [phone]; Fax: [phone]
http://ncwaterquality.org/wetlands