Stormwater Management Standards Manual - Toledo Metropolitan ...

The riser pipe should be a minimum of 24 inches in diameter for riser pipes up to 4 feet in height. Riser
pipes greater than 4 feet in height should be 48 inches in diameter. Riser pipes should be constructed
with poured-in-place concrete bottoms.
Buffer
A permanent buffer strip of vegetation extending at least 25 feet in width beyond the freeboard elevation
should be maintained or restored around the perimeter of all stormwater storage facilities. No lawn care
chemical applications should be applied to the buffer area, except to control noxious weeds or injurious
pests.
Additional Resources
Further details on stormwater wetland design may be obtained from other resources including:
Mecklenburg, Dan, Rainwater and Land Development, Second Edition, Ohio Department of Natural
Resources, Division of Soil and Water Conservation, 1996.
Maintenance
Maintenance Agreement
A legal entity should be designated or established with responsibility for inspecting and maintaining any
detention pond. The legal agreement should list specific maintenance responsibilities (including
timetables) and provide for the funding to cover inspection and maintenance.
Inlet & Outlet Inspections
The inlet and outlet of the pond should be checked periodically to ensure that flow structures are not
blocked by debris. Inspections should be conducted monthly during wet weather conditions from March
to November. It is important to design flow structures so that they can be easily inspected for debris
blockage, and so that corrective action can be taken even during storm conditions.
Erosion & Instability
Ponds should be inspected annually for erosion, destabilization of side slopes, embankment settling and
other signs of structural failure, and loss of storage volume due to sediment accumulation. Corrective
action should be taken in a timely manner upon identification of problems.
Embankment Maintenance
Embankments should be maintained to preserve their integrity as impoundment structures, including, but
not limited to, vegetative maintenance (mowing, control of woody vegetation), rodent control, erosion
control and repair, and outlet control structure maintenance and repair.
Hazardous Substance Storage
For sites where hazardous substances may be stored and used (e.g. certain commercial and industrial
developments), a spill response plan should be developed that clearly defines the emergency steps to
be taken in the event of an accidental release of harmful substances that may migrate to the pond. As a
result of this plan, design elements such as shut-off valves or gates may be needed.
Third Edition Stormwater Standards Manual September 2008 Page 97