The purpose of this chapter is to diminish threats to public health and safety caused by the runoff of excessive stormwater, reduce the possibilities of hydraulic overloading of sewer systems, and to reduce economic losses to individuals and the community at large. The provisions of this chapter further regulate, guide and control development which increases runoff of stormwater.
Except as hereinafter provided, that certain document titled "Cook County Watershed Management Ordinance", effective May 1, 2014, and any subsequent amendments thereto, three copies of which are on file at Village Hall for reference only, shall be and is hereby adopted as the ordinance for the Village regulating stormwater, erosion and sediment control practices, and sewer construction within the Village; and each and all of the regulations, provisions, penalties, conditions and terms of said Watershed Management Ordinance, as amended herein, on file at Village Hall, are hereby referred to, adopted and made part hereof as if fully set forth in this section.
The following sections of the WMO, as effective within the corporate boundaries of the Village, are hereby amended as follows:
Section 504.1: The requirements of this Section shall apply to any of the following:
A. Residential Subdivision Development on parcels greater than or equal to one (1) acre;
B. Multi-Family Residential Development on parcels of any size;
C. Non-Residential Development on parcels of any size; and
D. Right-of-way Development totaling one (1) acre or more of new impervious area, where practicable.
Section 504.13: The detention facility shall be designed and constructed to:
A. Be accessible and maintainable;
B. Function with a gravity outlet wherever possible;
C. Function without human intervention and under tailwater conditions;
D. Provide an overflow structure and overflow path that can safely convey the design runoff rate using the methodology specified in 502.9 of the Cook County Watershed Management Ordinance and no less than 1.0 cfs/acre of tributary area;
E. Maximum detention depths on new parking lots shall not exceed seven (7) inches within parking stalls and twelve (12) inches elsewhere, and the inundation hazard below the 100-year high water elevation shall be clearly posted;
F. Maximum water depth shall not exceed four feet
G. Maximum side slope shall be no less than 50:1 and no greater than 4:1, provided, however, that retaining walls may be incorporated into the design of the facility in lieu of the side slope requirements if approved by the Director;
H. Provide side slope stabilization and earth stabilization in a manner that is subject to the approval of the Director;
I. Roof-top detention shall be subject to the approval of the Director.
Section 504.14: The control structure for the detention facility shall be:
A. Designed using a baffle wall system
B. Located within the property boundary when possible;
C. Durable and permanent;
D. Visible and accessible for maintenance in the opinion of the Director;
E. Located on the outlet side of a manhole structure;
F. Designed to include a debris screen upstream of all restrictors less than six (6) inches in diameter;
G. Designed with a minimum two (2) inch diameter opening;
H. Designed to be self-cleaning; and
I. Designed to incorporate a backflow prevention device when connecting to the combined sewer system or a storm sewer system tributary to District water reclamation facilities.
(Ord. 3737, 4-8-2019)