in Mississippi

Madison, Rankin, Hinds, Forrest, Lamar, Hancock, Harrison, and Jackson to develop and
implement comprehensive stormwater management programs. Phase II also extended the
requirement of stormwater permitting and the subsequent implementation of stormwater
management programs for certain types of construction and industrial activities to all counties in
Mississippi and lowered the regulatory threshold from five acres to one acre.
In Mississippi, MDEQ regulates the stormwater permitting process. The General Permits Branch
of the Environmental Permits Division (EPD) oversees the development, issuance, and
maintenance of the general permits issued by EPD. Permits must be issued in accordance with
the provisions of the Mississippi Water Pollution Control Law (Code, § 49-17-1) and pursuant to
§ 402(b) of the Federal Water Pollution Control Act (33 U.S.C. 1251-1376).
Construction activities covering one to five acres within a county or municipality require the
Small Construction General Permit. Construction activities disturbing five or more acres require
the Large Construction Permit. Under either permit, construction may begin after the completion
of a Construction Notice of Intent (CNOI) to the MDEQ and the development and
implementation of the required Storm Water Pollution Prevention Plan (SWPPP). It is important
to note that MDEQ does not consider routine ditch and road maintenance as constituting
“construction” for the purposes of the permit.
The MDEQ reissued the Large Construction Storm Water General Permit (MSR10) for
construction activities on January 11, 2011. This general permit authorizes the discharge of
storm water from construction sites that disturb five or more acres by clearing, grading,
excavating, or other land disturbing activities. This permit replaces the previous general permit
that expired on May 31, 2010 and MDEQ administratively extended it. MDEQ’s reissue of the
permit for a five-year period will end on December 31, 2015.
Municipal Separate Storm Sewer Systems (MS4s)
An MS4 is a conveyance or system of conveyances that a public entity owns and uses to collect
or convey stormwater. MS4s include municipal or county owned storm drains, pipes, and
ditches, provided they are not part of a public sewage treatment plant.
The MS4 general permit authorizes a discharge or emission within a geographical area. The
permitting of selected storm sewer systems is required because of the EPA's Phase II Storm
Water Rule. This permit authorizes discharges of storm water from small municipal Separate
Storm Sewer Systems (MS4s), as defined in 40 C.F.R. § 122.26(b)(16).
Small MS4s within Mississippi are authorized to discharge under the terms and conditions of the
general MS4 permit provided they are either located in one of the aforementioned urbanized
counties as determined by the latest census and pursuant to 40 C.F.R. § 122.32 or have been
designated by the MDEQ pursuant to 40 C.F.R. §§ 122.32(a)(2), 122.32(b), or 123.35(b)(3) or
(4).
For the Mississippi Department of Transportation, permit coverage must be obtained for the
entire counties (including cities within) of DeSoto, Forrest, Hancock, Harrison, Hinds, Jackson,
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