20091219 Ver 1_Information Letter_20100120

S T ATE OF NORTH CAROLINA
DEPARTMENT OF TRANSPORTATION
BEVERL)- EAVES PERDUE
GOVERNOR
NC Division of Water Quality
1650 Mail Service Center
Raleigh, NC 27699-1650
Attention: Ms. Coleen FL Sullins
Director
Dear Madam,
EUGENE A. CONTI, 1R
SWRETARY
January 15, 2010
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Q JAN 3 0 2010
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Subject: B-4604 Response to NC Division of Water Quality (NCDWQ) Letter.
As you are aware, the NC Department of Transportation submitted a permit application on
November 9, 2009 for TIP Project B-4604 to NCDWQ. This letter addresses each item in
NCDWQ's January 7, 2010, letter regarding the, replacement of the Bridges 13 over Indian Well
Swamp on SR 1753 in Pitt Couwy. A copy is attached for your convenience.
I . Buffer impacts have been recalculated and plan sheets revised and included.
2. Buffer impacts fall below the 150' length threshold and the 1/3 acre threshold and are
allowable.
3. This area is too steep for sheetflow and the drainage ditch is needed for stormwater
treatment. The pre-formed scour hole (PSH) performs the same function on the opposite
side. A copy of the revised stormwater management plan is also included.
Additionally, NCDOT Utility Unit has determined that 0.15 acre of hand clearing in wetlands is
necessary due to the change in relocatio? of powcr lines. The plan sheet is attached.
If you have any further questions, please contact Chris Underwood at [phone].
Sincerely,
V X' Gregor?? J. 'horpe, Ph.D, Manager
? Project Development & Environmental Analysis Branch
cc: w/attachments
Mr. 'fon3 Steffens, USACE
Mr. Jay Johnson. Division 2 Environmental Officer
IN/Ir. Garcy Ward. NCDWQ
MAILING ADDRESS: TELEPHONE. [phone] LOCATION:
NC DEPARTMENT OF TRANSPORTATION' FAY.. 919-733-9794 TRANSPORTATION BUILDING
PROJECT DE` -LOPMEN F ANO ENVIRONMENTAL ANALYSIS 1 SOUTH W ILVINCTON ST PE ET
1948 MAIL SERVICE CENTER WEBSITE: WWAI NCDOT.ORG RALEIGH NO
RALEICr. NO 27899-1548
?y iA
HC®ENR
North Carolina Department of Environment and Natural Resources
Division of Water Quality
Beverly Eaves Perdue Colleen H. Sullins
Governor Director
January 7, 2010
CERTIFIED MAIL - RETURN RECEIPT REQUESTED
Dr. Greg Thorpe, PhD., Manager
Planning and Environmental Branch
North Carolina Department of Transportation
1548 Mail Service Center
Raleigh, North Carolina, 27699-1548
Dee Freeman
Secretary
Subject: Replacement of Bridge No. 13 over Indian Well Swamp on SR 1753 in Pitt County, Federal Aid
Project No. BRZ-1753(l ), State Project No. 8.222240 1, TIP B-4604.
Dear Dr. Thorpe:
The NC Division of Water Quality has reviewed your submittal for a 401 Water Quality Certification and
Neuse Buffer Authorization for the aforementioned project. Review of your application revealed it
lacking necessary information required for making an informed permit decision. The permit application
was deficient in the following areas:
• Buffer impacts calculated incorrectly. It was stated in the Stormwater Management Plan,
for the area south of the bridge that includes the service road that "Since water runs away
from the stream, this area should not be counted as buffer even though it is within fifty feet of
the top of bank." This is incorrect. All impacts within the fifty foot buffer should be
counted unless the facility or structure is pre-existing. Please modify your buffer impact
calculations and plan sheets to include impacts within this area.
• Buffer mitigation. It was unclear from the application why buffer mitigation is needed for
this project. Pease explain why buffer mitigation is being requested.
• Ditches through buffers. Your plans call for creating new drainage ditches through the
buffer on the south side of the bridge between the -L- and -DRI - and the -L- and -DR2-.
Please explain more clearly why stormwater can't sheetflow through this area and why the
drainage ditches are needed.
According to the Neuse Buffer Rules (15A NCAC 2B .0233 (6)), new ditches are allowable
in the buffer Only ira facility is installed to control nitiugeo and attenuate flow before the
convevance discharges through the buffer. Grass swales can be used to accomplish this for
linear transportation projects at the ratio of 100' of grass swale per acre of drainage. The
narrative in your application states that grass swales will be used in this area but this is not
clearly shown on the plan sheets. If it is determined that ditches are needed here, please
provide data showing that the above mentioned ratio is being met.
Transportation Permitting Unit
1650 Mail service Center, Raleigh, North Carolina 27699-1650
Location: 2321 Crabtree Blvd., Raleigh, North Caroline 27604
Pncne: 919-733-17861 FAX: [phone]
Intemet hrpYfh2o enr.state.nc.uslnmeUandsJ
One
NorthCarolina
?atura!!r/
An Equal Opportunity 1 ru5mna" Action Ern*yer
STORM'V`/ATER MANAGEMENT PLAN
Project: 3379
TiP No. B-4604
Pitt County
Date: 1/7,12010
Hydraulics Project Manager: James R. Rice, P.E. (HDR),
Marshal Clawson, P.E. (NCDOT Hydraulics Unit)
ROADWAY DESCRIPTION
The project B-4604 consists of constructing a new bridge 100 feet long to replace the
existing bridge #13 in Pitt County on SR 1753 over Indian Wells Swamp. The total
project length is 0.085 miles. The project creates impacts to Indian Wells Swamp, which
is located in the Neuse River Basin. The project drainage system consists of deck drains
and a closed system to discharge remaining bridge drainage outside the buffers for
treatment.
Jurisdictional Stream_ Indian Wells Swamp
ENVIRONMENTAL DESCRIPTION
The project is located within the Neuse River Basin and Pitt County which is not a
LAMA county. Indian Wells Swamp has been classified as a jurisdictional stream and
therefore riparian buffer rules apply. In order to maintain existing drainage patterns and
accommodate the service road, special cut and tail ditches were required on the southeast
and southwest corners. On the southwest corner, the ditch drainage was able to be picked
up in the system draining the bridge. This water is being treated with a Pre-Formed
Scour Hole outside of the wetlands and buffers. On the southeast corner, there wasn't an
opportunity to discharge the ditch outside the buffers, so to ensure stability, this ditch was
carried through the buffers. All of this stormwater is treated by grass swales on-site.
There are wetland areas that will be impacted by the proposed project. Wetland impacts
have been reduced to a minunurn by keeping roadway fill slopes at 3:1 and utility access
roads as close to the L line as possible. At the bridge, a 3-span bridge with a large center
span will he utilized to reduce the need for piers in the channel. The impacts to the
Indian Wells Swamp surface waters will be the removal of the existing piers, a small
impact due to the proposed piers, and the tie in of the tail ditch.
The existing structure has deck drains that discharge directly into the surface water.
Deck drains have been added to the proposed structure. The.deck drains on the proposed
structure will not discharge directly into the surface water, but they will discharge on the
spill-through rip rap under the bridge. Deck drains were required due to the length of the
strucun'e, the structure vrnfile's low gradient. and width of shoulder.
BEST MANAGEMENT PRACTICES AND MAJOR STRUCTURES
The primary goal of Best Management Practices (BMPs) is to prevent degradation of the
states surface waters by the location, construction and operation of the highway system.
'rhe BMPs are activities, practices and procedures taken to prevent or reduce stormwater
pollution and should be used whenever possible.
The BMP measures used on this project to reduce stormwater impacts are:
Grass Swales (See attached ditch comps and grass swale comps)
All ditches on the,job provide treatment
o Pre-Formed Scour Hole
o Bridge Deck Drains have been placed so they do not directly discharge into
fndian Wells Swamp.

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