[R.O. 1998 § 550.600; Ord. No. 2802 §1, 7-17-2012]
A.
New flood management projects located within
the co-permittee's jurisdiction must be assessed for impacts on water
quality. Existing projects must be assessed for incorporation of additional
water quality protection devices or practices, where feasible. Flood
management projects in the plan area can include: regional stormwater
control (retention basins, detention basins); flood control levees
and associated pump stations; stormwater drainage conveyance capacity
improvements; projects involving land buyouts; and designated uses
of floodplain land.
B.
Stormwater management projects in both
development and redevelopment will be assessed for water quality impact,
according to MSD's "Rules and Regulations and Engineering Design Requirements
for Storm Water Drainage Facilities," which address the Storm Water
Management Plan water quality requirements under MCM 5. All flood
management projects involving channel modification will also be assessed
for aquatic and water quality impacts through the Corps of Engineers
404 permit and MDNR 401 water quality certification process.
[R.O. 1998 § 550.610; Ord. No. 2802 §1, 7-17-2012]
Existing projects located within
the plan area: none at this time.
[R.O. 1998 § 550.620; Ord. No. 2802 §1, 7-17-2012]
All co-permittees that plan, design
or install flood management projects are subject to this Article.
MSD has general responsibility for stormwater drainage facilities
in the plan area. St. Louis County, municipalities, and property owners
have responsibility for the drainage facilities not dedicated to,
and maintained by MSD. St. Louis County and municipalities maintain
control over planning and zoning, land use regulations, and floodplain
management through ordinances.
[R.O. 1998 § 550.630; Ord. No. 2802 §1, 7-17-2012]
A.
Implement and enforce ordinances and/or
procedures requiring that water quality factors be incorporated into
the design and operation of stormwater/flood control structures.
B.
Inspect existing flood management facilities
on a specified frequency to determine water quality impacts and exploit
opportunities for improvement.
C.
Existing control structures undergoing
renovation are modified to the maximum extent practicable to meet
new construction criteria in MSD's "Rules and Regulations and Engineering
Design Requirements for Sanitary Sewage and Stormwater Drainage Facilities."
D.
Design new flood management projects to
prevent or minimize adverse water quality impacts, exploring alternative
programs utilizing non-structural flood damage reduction and stream
bank stabilization measures to the maximum extent practicable.
E.
Use models based on fully developed conditions,
and adopt a free board above base flood elevation for development.
F.
Identify existing wetlands or other natural
open space areas, particularly around streams, and preserve them from
development so they can provide natural attenuation, retention or
detention of runoff.
G.
Survey watersheds downstream from proposed
projects to determine potential water quality impacts. Design proposed
projects to minimize downstream impact.
H.
Work closely with local governments, environmental
organizations and others to develop multi-use open space corridors
along streams which will allow for over-bank floodplain storage.
I.
Floodplains are preserved to the maximum
extent practicable.
J.
Use non-structural flood management practices
to the maximum extent practicable, utilizing acquisition of flood-prone
property where possible.
K.
Open stormwater conveyance systems are
used to the maximum extent practicable to preserve natural conditions
and habitat.
L.
Channel improvement projects are to use
natural approaches rather than concrete, riprap or other "hard" techniques
to the maximum extent practicable.
M.
Inlets and outlets from closed portions
of conveyance systems are designed to minimize scour and erosion.
N.
Trash racks are provided at outlet structures
of detention ponds and other flood control structures to capture trash
and floatables.
O.
Employ natural solutions and use controls
that preserve the hydrology of a site as a first line of flood control
to the maximum extent practicable.
[R.O. 1998 § 550.640; Ord. No. 2802 §1, 7-17-2012]
Employees and contractors responsible for the planning and design of the flood management projects identified in Section 550.600 will be trained on the BMPs in this Article. In addition, employees performing this work will be familiar with MSD's rules and regulations and engineering design requirements for stormwater drainage facilities.
