Colonial Ridge_Kelly_Johnson_NCDENRRCDENR
North Carolina Department of Environment and Natural Resources
Division of Water Quality
Beverly Eaves Perdue Coleen H. Sullins
Governor Director
February 10, 2009
Mr. Sam Burgess
230 Government Center Dr.
Suite 150
Wilmington, NC 28403
Subject; New Hanover County Planning Dept Review, Colonial Ridge
Dear Mr. Burgess:
Dee Freeman
Secretary
The Wilmington Regional Office has received the planning review request and has the following initial
comments:
Permit: The site will require a State Stormwater permit because it will require an
Erosion and Sediment Control Plan because the site is over an acre. The permit will be
issued under SL 2008-211.
2. Density and Receiving Water: The receiving water is not specified on the plans, and
must be verified at a future time. If the receiving water is close to shellfish (SA) or
outstanding resource waters (ORW), then there are more stringent requirements to
meet. The amount of imperviousness is not specified on the plan, but it appears that it
will be high density rather than low density.
a. Low density and not SA or ORW: If the site's built upon area (BUA) is less than
24% it will be a low-density project. Low-density projects must locate the higher
density areas in upland areas and away from surface waters and drainageways.
If the project is low density please be aware of this requirement, as it is a recent
(2008) regulatory requirement. Low-density projects do not require structural
stormwater best management practices (BMPs),
b. High-density and not SA or ORW: If the site's BUA is greater than 24% it will be
a high-density project. High-density projects require structural stormwater BMPs.
It appears that infiltration devices will be used. Mr. Vincent Lewis with DENRISoil
and Water must visit each site to determine water table and infiltration rate data.
This is typically done before applying for a stormwater permit. He can be
reached at 910.796.7378. Please ensure that BMPs are designed in accordance
with the Division of Water Quality's Stormwater BMP Manual, 15A NCAC 02B
.1000, and SL 2008-211. In particular, please be aware that the bottom of the
infiltration device must be at least two feet above the seasonal high water table,
and that vegetated filters are required from the overflow of all infiltration systems.
Wilmington Regional Office
127 Cardinal Drive Extension, Wilmington, North Carolina 28405 One
Phone: 910-796-72151 FAX: 910-350-20041 Customer Service: 1.877-623-6748 North Cal ollna
Internet: vrruw.ncwaterquality,org
An Equal Opportunity 1 Affirmative Action Employer 6i
Colonial Ridge
Page 2 of 2
Vegetated filters and their associated level spreaders must be designed for the
10yr peak flow. If you would like additional information on your options in sizing
infiltration systems please contact my office.
c. SA or ORW: If the site is found to be within a half-mile and draining to shellfish
waters (SA), or if it is within 575ft of outstanding resource water (ORW), then the
site will be considered high density if it is over 12% BUA.
3. Wetlands:
a. Water must enter the wetland at a non-erosive velocity. The DWQ defines non-
erosive velocity as 2fUsec from the 10yr peak flow.
b. There will be questions about the mulch trail through the wetland when the
project is submitted.
4. Buffers: A 50-foot vegetated buffer is required for all new development. A 30-foot
vegetated buffer is required for all redevelopment. The buffer is around streams, rivers
and tidal waters. The specifics of how to measure this buffer and the definition of
"redevelopment" are available in SL 2008-211. However, this may be of particular
interest to this site if the wetlands shown are coastal (tidal) wetlands.
This is a brief overview, and represents only my initial guidance for permitting. If you have any
questions please feel free to call me at (910) 796-7215 or email me at kelly.p.johnson@ncmail.net.
Since
Kelf`y Johns6n
Environmental Engineer
GSIKJ: S:IWQSIStormWater\Letters120091Colonial Ridge NHC Planning.feb09
Wilmington Regional Office
127 Cardinal Drive Extension, Wilmington, North Carolina 28405
Phone: 910-796-72151 FAX: 910-350-20041 Customer Service: 1-877.623-6748
Internet: www.ncwaterquality.org
An Equal Opportunity1 Affirmative Action Employer
NorthCarolina
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