Exh 7AAGENDA ITEM #7A
MARCH 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 ON-SITE
STORAGE REQUIREMENTS AND TREATMENT, FLOODPLAIN STORAGE,
AND NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM
(NDPES) REQUIREMENTS, AND PROVIDING AN EFFECTIVE DATE
BE IT ENACTED BY THE CITY COMMISSION ON BEHALF OF THE PEOPLE OF
THE CITY OF ATLANTIC BEACH, FLORIDA:
Section 24-67. Development review and issuances of development aermits; revise (d)
Stormwater drainage requirements, to read:
(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 Storage: The applicant will be required to provide on-site storage such that
there is no increase in the rate or volume of flow to off-site, from every developed or
redeveloped pazcel, and provide documentations and calculations to demonstrate compliance
Subdivisions and developments previously permitted by the St. Johns River Water M ement
District (SJRWMD), and have an in compliance retention/detention system that collects and
controls run-off, are exempt. The requirement for on-site storage may be waived by the Director
of Public Works if storage is determined to be unnecessary or unattainable.
Volume calculations for lots that require on-site storage should be based on the difference
in run-ofFvolume generated by the new impervious azea ("delta volume") and would be
calculated bv:
V=CAR/12, where
V =volume of storage in cubic feet,
A = area of the lot in scauaze feet,
R = 25 year and 24 hour rainfall dept~9.3 inches) over the Iot area, and
C =run-off coefficient, which is 0.6 for the 50% maximum imperviousness 0 4 for 25%
imperviousness, and 0.2 for 0% imperviousness.
AGENDA ITEM #7A
MARCH 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 pazcel 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 azeas in the 100-near
floodplain, where a floodplain elevation has been defined by either the Federal Emergency
Management Agency (FEMA) on Flood Insurance Rate Maps (FIRMS), the 1995 Stormwater
Master Plan, the Core City_proiect, or the 2002 Stormwater Master Plan Update (e.g., Hopkins
Creek). Site grading shall create storage on-site to mitigate for filling of volume on-site. This
stora.~e is in addition to the storage required for the increase in impervious azea.
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 (~ inch
of rainfall; or as an option, for facilities with a drainage azea of less than one hundred (100
acres, the first one-half (1/z) inch of run-offpursuant 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~f
this Section.
5. NPDES Requirements: All construction activities shall be in conformance with the
City's National Pollutant Discharge Elimination Systems (NPDES) 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 (BMPsZprior to
discharge into natural or artificial drainage systems. Beginning May 1 2003 all construction
projects of one acre or more will require a NPDES permit_
6. Enforcement: Subsequent to approval of a property owner's final grading including
on site and/or flood plain storage and stormwater treatment, the improvements shall be
maintained by the property owner. Failure to maintain the improvements will require restoration
upon notification by the Director of Public Works within a stipulated timeframe If restoration
is not timely completed, the City shall have the right to complete the restoration and the City's
actual costs incurred, together with a charge of 100% of said costs to cover the City's
administrative expenses, shall be charged to the owner.
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
City Clerk
John S. Meserve
Mayor, Presiding Officer
Alan C. Jensen, Esquire
City Attorney