Exh 7CAGENDA ITEM 7C
FEBRUARY 24, 2003
CITY OF ATLANTIC BEACH. FLORIDA
ORDINANCE NO. 90-03-180
AN ORDINANCE OF THE CITY OF ATLANTIC BEACH, FLORIDA,
AMENDING CHAPTER 24, ZONING, SUBDIVISION AND LAND
DEVELOPMENT REGULATIONS, TO ESTABLISH STORMWATER OFF-SITE
STORAGE REQUIREMENTS AND TREATMENT, FLOODPLAIN STORAGE,
AND NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM
(NDPES) REQUIREMENTS, AND PROVIDING AN EFFETIVE DATE
BE IT ENACTED BY THE CITY COMMISSION ON BEHALF OF THE PEOPLE OF
THE CITY OF ATLANTIC BEACH, FLORIDA:
SECTION 1. Sec. 24-67(d) is hereby amended to read as follows:
Section 24-67 Development review and issuances of development Hermits
(d) Stormwater drainage, storage and treatment requirements.
1. Topography and Grading: All lots and development sites shall be constructed and
graded in such a manner so that the stormwater drains to the adjacent street, an existing natural
element used to convey stormwater (See section 22-303, definitions: Stormwater management
system), or a city drainage structure after meeting on-site storage requirements, as listed in this
Section. The city shall be provided with apre-construction topographical survey prior to the
issuance of a development permit and apost-construction topographical survey prior to the
issuance of a certificate of occupancy. The surveys shall be prepared by a licensed Florida
surveyor, and the requirement for either or both surveys may be waived by the Director of Public
Works if they are determined to be unnecessary.
2 On-Site Stora~e~ The applicant will be required to provide on-site storage such that
there is no increase in the rate or volume of flow to ofl=site, from every developed or
redeveloped parcel and provide documentations and calculations to demonstrate compliance.
Subdivisions and developments yreviousl~permitted by the St. Johns River Water Management
District (SJRWMD) and have an in-compliance retention/detention system that collects and
controls run-off, are exempt.
Volume calculations for lots that require on-site storage should be based on the difference
in run-off vohune generated bkthe new impervious area ("delta volume") and would be
calculated bv:
V=CAR/I2, where
V =volume of storage in cubic feet,
A =area of the lot in square feet,
R = 25 Rear and 24 hour rainfall depth (9.3 inched over the lot area, and
C =run-oil coefficient, which is 0.6 for the 50% maximum imperviousness, 0.4 for 25%
imperviousness, and 0.2 for 0% imperviousness.
AGENDA ITEM 7C
FEBRUARY 24, 2003
This delta volume (post V minus pre V in cubic feet must be stored at least 1 foot above
the wet season water table and below the overflow point to off-site (in many cases this may be
the adjacent road elevation. As an option, and as approved by the Director of Public Works, the
owner of the parcel to be developed or redeveloped may implement, at the applicant's cost off-
site storage and necessary conveyance to control existing flood stages off-site.
3 Flood Plain Storage: There shall be no net loss of storage for areas in the 100-~
floodplain where a floodplain elevationhas been defined by either the Federal Emergency
Management Agenc~(FEMA) on Flood Insurance Rate Mays (FIRMS) the 1995 Stormwater
Master Plan the Core Cif project, or the 20Q2 Stormwater Master Plan Update (e.g., Hopkins
Creek Site grading shall create storage on-site to mitigate for filling of volume on-site. This
storage is in addition to the storage required for the increase in impervious area.
4 Stormwater Treatment: Stormwater treatment shall be provided for a volume
~uivalent to either retention or detention with filtration, of the run-off from the first one (11 inch
of rainfall- or as an option. for facilities with a drainage area of less than one hundred (100)
acres the first one-half (1/2~ inch of run-off pursuant to Chapter 62-25, Florida Administrative
Code (FAC) No discharge from any stormwater facility shall cause or contribute to a violation
of water quality standards as provided in Section 62.302 of the Florida Administrative Code.
This treatment volume can be included as ,part of the on-site storage requirement in item d (2;I of
this Section.
5 NPDES Requirements: All construction activities shall be in conformance with the
Cites National Pollutant Discharge Elimination Systems DES) permit, in addition to the
requirements of the Water Management District and the Florida Department of Environmental
Protection. NPDES requirements include use of Best Management Practices BMPs~prior to
discharge into natural or artificial drainage systems. Beginning April 1, 2003, all construction
projects of one acre or more will require a NPDES permit.
SECTION 2. This ordinance shall take effect immediately upon its final passage and adoption
Passed by the City Commission on first reading this day of , 2003.
Passed by the City Commission on the second and final reading this day of
.2003.
ATTEST:
Maureen King John S. Meserve
City Clerk Mayor, Presiding Officer
Alan C. Jensen, Esquire
City Attorney
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Ordinance No. 90-03-180