TRANSMITTAL LETTER FOR BOARD MEETING OF MAY 6, 2021
COMMITTEE ON STORMWATER MANAGEMENT
Mr. Brian A. Perkovich, Executive Director
Title
Report on Green Infrastructure, Detention, and Compensatory Storage Volumes Required by the Watershed Management Ordinance
Body
Dear Sir:
The Watershed Management Ordinance (WMO) regulates sewer construction within the District’s service area and development within suburban Cook County. It provides uniform stormwater management regulations to prevent future development projects from exacerbating flooding and protect environmentally sensitive areas. Green infrastructure (GI) is installed to comply with the stormwater management requirement of capturing one inch of stormwater runoff from all impervious surfaces of the development. Detention requires site runoff to be retained and controls the rate at which water is released, and compensatory storage is required to mitigate development impacting the floodplain.
When a WMO permit is required, development must comply with the stormwater management provisions of the WMO. The first of the two attached tables includes the number of permits issued per quarter since the WMO became effective. It also summarizes the development area, volume captured by GI, detention provided, and compensatory storage. The total for each year and running total are also provided. The second table includes offsite stormwater facility information. There were no permits issued utilizing offsite volume control storage, however one permit was issued during the second quarter of 2020 that used offsite detention storage. These tables will continue to be updated at the end of each quarter and transmitted for your information. This report covers first quarter of 2021.
Respectfully Submitted, Catherine A. O’Connor, Director of Engineering, KMF:MD
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