HomeMy Public PortalAboutORD15419 BILL NO. 2015-26
SPONSORED BY COUNCILMAN Scrivner
ORDINANCE NO. / S-4-1
AN ORDINANCE AMENDING THE CODE OF THE CITY OF JEFFERSON, MISSOURI,
PERTAINING TO STORMWATER / FLOODPLAIN MANAGEMENT.
BE IT ENACTED BY THE COUNCIL OF THE CITY OF JEFFERSON, MISSOURI, AS
FOLLOWS:
Section 1. Article I. General of Chapter 31 (Stormwater/Floodplain Management)
Section 120 Definitions, and Article II. Stormwater Management, of Chapter 31
(Stormwater/Floodplain Management) of the Code of the City of Jefferson, Missouri, is
amended as follows:
Section 31-120 Definitions.
AWPA MARC: The American Public Works Association /Mid-America Regional Council Manual for Best
Management Practices for Stormwater Quality, as amended from time to time by MARC and including all
additions and exceptions kept on file by the City.
Water Quality Storm. The first 1.37 inches of rainfall in a 24-hour period.
Water Quality Volume. The volume of runoff created by the water quality storm as calculated using the
hydrology methods stated in the APWA MARC manual section 6.2 shortcut method and section 6.4 rational
method.
Section 31-200 General Requirements.
A. Design Criteria ,
I. Storm Drainage Systems and Facilities: The design procedures stipulated in the KC-APWA 5600
shall be followed insofar as it is applicable. Written justification for all deviations must be
prepared and submitted in accordance with the variance procedures set forth in this chapter.
2. Erosion and Sediment Control: The design procedures stipulated in the latest edition of the KC-
APWA 5100 shall be followed insofar as it is applicable. Written justification for all deviations
must be prepared and submitted in accordance with the variance procedures set forth in this
chapter.
3. Post Construction Stormwater Quality: The hydrology methods outlined in the latest edition
of the APWA MARC manual shall be followed in the calculation of water quality volume.
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B. Standard Drawings: The City of Jefferson Standard Details, as amended from time to time, as well as the
Kansas City Metro Chapter of the American Public Works Association, Division 5300, Standard Drawings
(KC-APWA 5300)shall be referenced as necessary for design and construction. When the two documents
conflict, the City of Jefferson Standard Details shall rule.
C. Plan Requirements: Plans shall include all drawings. narratives and computations as outlined in KC-APWA
5100 and 5600.
D. Drainage onto sidewalks.Tributary areas where sidewalks exist or are proposed, and which drain across a
public sidewalk, must not exceed three thousand(3,000)square feet of impervious area, including roofs
discharging upon paved areas,or nine thousand(9,000)square feet of sodded areas, or in proportional
amounts for a combination of such areas. Paved, roofed or other impervious areas exceeding three thousand
(3,000)square feet shall be provided with drains for discharge into storm conduits, channels. or street
gutters.
E. Downspouts. Downspouts shall not be discharged directly onto sidewalks or entrance ways. When
downspouts are connected to the gutterline of the street or the public drainage system.they shall be
connected by a method approved by the Director. Downspouts shall not discharge within the building
setback unless there is a drainage swale established to carry the water to the front or rear of the property or
closest natural drainage course. Downspouts may also discharge within the building setback if discharging
into a rain garden, rain barrel or other stormwater management practice.
F. Flow toward streets. Any concentration of surface flow in excess of two(2)cubic feet per second(cfs)for
the ten-year frequency rain shall be intercepted before reaching the street right-of-way and shall be carried
by an enclosed storm drain to connect with a drainage structure at the low point in the street right-of-way or
to discharge to a watercourse.
G. Parking lots and garages. Adequate provisions shall be made for the disposal of stormwater from parking
lots and garages. Plans shall be submitted for approval to the Director to ensure measures are taken to limit
the flow of water onto adjoining property or adjacent sidewalks or streets in a quantity that would be
detrimental to or inconvenient to persons using the streets or sidewalks.
H. Natural Stream Protection On Developments Planed after April 1.2007.
I. Natural streams containing an ordinary high water mark with a drainage area of 50 acres or greater
shall be buffered by a natural stream protection buffer consisting of a twenty-five(25) foot
riparian zone plus a thirty-five(35)foot building setback.
2. If a channel enclosure or relocation of such a drainageway is permitted by the City the riparian
zone shall not be required and building setbacks will revert to those dictated by zoning.
3. Riparian zones shall remain undisturbed to the maximum extent practicable. This zone prohibits
any land disturbance, clearing, grubbing, or any other construction activities except as necessary
for utility construction,greenways and road access.Naturally occurring vegetation within the
riparian zone shall not be removed, diminished, inhibited, mowed or substantially altered from its
• natural state or growth. Such construction shall minimize disturbance of the stream and riparian
zone.
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4. Adjustments in widths of the riparian zone or adjacent building setback may be made when
approved by the Director when local conditions justify deviation from the standard widths.
5. Wherever the designated riparian zone must be disturbed, mitigation measures shall be taken to re-
establish vegetative filtration and stream stabilization to the maximum extent practicable.
I_ Post Construction Water Quality
L The water quality volume shall be managed using Best Management Practices(BMPs) to the
maximum extent practicable(MEP).
2. All industry standard water quality treatment options are available to the designer and will
be evaluated during plan review. If extended detention time is proposed as a BMP the
minimum residence time shall be six hours and the maximum residence time shall be 72
hours.
3. For plan approval,a post construction water quality plan must be developed and must
include a written operation and maintenance document for all BMPs.
4. Private post construction water quality BMPs shall be maintained by the owner in
accordance with the approved operation and maintenance document.
Section 2. This Ordinance shall be in full force and effect from and after the date
of its passage and approval.
Passed: Q- ).0I s201.s— Approved: vvv t oZif ;-19/5-
Ccwue,. fittru, eam,ce,-
Presiding Officer._ Mayor Carrie Tergin
ATTEST:-- APPROVED AS TO FORM:
City"Clerk` \ . " City Counselor
Drafters Note:Original text shown as thus.Text changed from the original shown as thus.
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