20001195 Ver 16_Stormwater Info_20210905

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hdrinc.com
September 5, 2017
Karen Higgins
DWR — 401 & Buffer Permitting Branch
1617 Mail Service Center
512 N. Salisbury St.
Raleigh, NC 27699-1617
RE: Charlotte Douglas International Airport
DWQ#: EXP 00-1195v6, Mecklenburg County
Request for SWMP Modification
Dear Ms. Higgins,
HDR, on behalf of the Charlotte Douglas International Airport (CLT) is hereby requesting
modification to the Stormwater Management Plan (SWMP) that was developed and approved by
NCDENR Division of Water Quality as part of waters of the US impacts associated with the
construction of CLT's third parallel runway and other airport improvements. CLT initiated these
improvements from 2006-2010. Subsequent to the completion of these airport improvements and
receipt of approval of the SWMP, CLT has been initiating the various activities as part of their
activities to maintain their facilities, including the sweeping of pavements identified in their plan.
The area within the operational footprint of the airfield by which these stormwater control measures
are performing appear to be functioning to produce high quality runoff. The amount of impervious is
limited as a percentage of the overall drainage area, and the pervious areas are managed by
airport maintenance staff with regular mowing and stabilization activities. As these pavement
surfaces are used by aircraft, the pollutant runoff is seen to be low as compared to a typical public
roadway. Wallace Neel Road, the only public roadway being swept as part of this plan doesn't
contain a curb and gutter section, as such runoff is being treated through grass shoulders and a
managed grass swale.
It is therefore HDR's opinion that CLT's SWMP can achieve the intended results without continuing
the sweeping operation. Therefore, CLT is seeking to terminate any future sweeping activity as part
of the SWMP compliance. CLT does maintain a vigorous inspection and foreign object debris (FOD)
removal of all airfield pavements for the protection of aircraft operations. This can include pavement
sweeping which inherently will have a water quality benefit. This procedure will be maintained but
not for the purpose of tracking pollutant removal or its effectiveness.
As a courtesy, the attached information provides some perspective into the results of sweeping
these types of pavements, which may aid DEQ in support of this decision and other practices on
airport property.
440 S Church Street, Suite 1000, Charlotte, NC 28202-2075
704.338.6700

Please advise if additional information is required for this review, and what additional steps are
necessary to document the modification of CLT's SWMP.
Please let me know if you have any questions.
Sincerely,
HDR Engineering, Inc. of the Carolinas
� Z�W 01 40 �1
Ron A. Geiger, PE
Project Manager
cc: Chad Huskins, CLT
Jimmy Jordan, CLT
Sue Homewood, DWR, Winston Salem

Summary of Sweeping Operation at Charlotte Douglas International Airport
Wallace Neel Road
---
Runways/Taxiways
--
Year Avg. Load per Total Load,
-- —
Year Avg. Load per Total Load,
Trip, lbs. lbs.
Trip, lbs. lbs.
2010 134
8,040
2010
316
6,630
2011 180
— --
5.230
2011
288
11,230
2012 189
-- -
7,405
-
—
2012
213
18,095
2013 522
25,345
----_
2013
1,780
154,890
2014 231
9,925
_
2014
4,004
44,050
2015 1063
6,380
2015
2,011
8,045
2016 825
—
_ 28,080
2016_
1,583
14,168
2017 798
4,785
2017
577
4,040