Section 12A-88 Stormwater management plan required.
Prior to the adoption of Ord. 19442 on 03/05/2007, Section 12A-88 read as follows.
(a) A stormwater management plan is required for all
development and redevelopment
projects subject to this article.
(b) A stormwater management plan must be submitted
and approved by the director before
issuance of a land disturbance permit and before approval of a final plat or a development plan.
The stormwater management plan shall be prepared and certified by a registered professional
engineer licensed in the State of Missouri.
(c) The stormwater management plan must show all components
of the storm drainage
system including street curbs, inlets and piping, junction boxes, engineered and natural channels
and stormwater management facilities (for example, retention and detention ponds, bioswales,
bioretention areas, etc.). The stormwater management plan may be prepared in conjunction with
or separate from the soil erosion plan.
(d) It is recommended that a preliminary stormwater
management plan be submitted early in
the review process to allow time for city staff to discuss plan concepts with the developer. The
stormwater management plan will be discussed as part of the concept review for any proposed
(e) The stormwater management plan must comply with
all requirements of the citys current
Stormwater Management and Water Quality Manual.
(f) The following information must be submitted with
a stormwater management plan:
(1) Worksheets. All calculations and worksheets used in plan preparation
and BMP selection.
(2) Calculations. Hydrologic and hydraulic design calculations for the
post-development for the design conditions specified in the Stormwater Management and Water
Quality Manual. These calculations shall include: description of the design storm frequency,
intensity and duration; time of concentration; soil curve numbers; peak runoff rates and total
volumes for the watershed area; infiltration rates where applicable; culvert capacities; flow
velocities; data on the increase in rate and volume of runoff for the design storms referenced in
the Stormwater Management and Water Quality Manual; and, documentation of sources for all
computation methods and field test results.
(3) Soils information. When a stormwater management facility relies
on the hydrologic
properties of the soils (such as an infiltration basin) the developer shall submit a soils report. The
soils report shall be based on onsite boring logs or pit profiles. The number and location of
required soil boring or soil pits shall be determined based on what is needed to determine the
suitability and distribution of soil types present at the location of the facility.
(4) Landscaping information. The developer must include a detailed landscaping
vegetative restoration plan as part of the stormwater management plan. Details on maintenance
of the vegetation shall be included in the operation and maintenance plan. The landscaping plan
component must be prepared by an individual who can demonstrate knowledge of landscape
design or by Missouri Department of Conservation personnel.
(g) The stormwater management plan must include a
written operation and maintenance
manual for the permanent stormwater management facilities, including landscaping and
vegetative cover, proposed as part of the development. This is required whether the facilities are
to be publicly or privately maintained. Approval of the operation and maintenance manual is a
part of the overall plan approval process.