TRANSMITTAL LETTER FOR BOARD MEETING OF JUNE 20, 2013
COMMITTEE ON STORMWATER MANAGEMENT
Mr. David St. Pierre, Executive Director
Title
Request for approval to initiate design of Project DPR-14D of the Lower Des Plaines River Watershed Plan
Body
Dear Sir:
Severe flooding occurred when Lyons Levee was overtopped by the Des Plaines River in the Village of Forest View (Village) as a result of the severe rainfall event that occurred on April 18-19, 2013. The Village reported that all 270 homes within the Village and numerous businesses located along Harlem Avenue sustained flooding damages as a result of this event. Attached for your reference are two exhibits: potential inundation area and actual flooding area from the April 18-19 event.
Lyons Levee was constructed by the District circa 1900 on District property. The property was sold to the Forest Preserve District of Cook County (FPDCC) in 1950. Project DPR-14D called for raising the existing levee by 2-3 feet to prevent overtopping and flooding during a 100-year rain event. The DWP benefit-to-cost ratio of DPR-14D was 0.03 with benefits of $8.6 million and a cost of $260.9 million. The high cost was attributed to compensatory storage believed to be required based on input during DWP development from appropriate regulatory agencies in order to allow for the levee to be improved.
Numerous meetings have occurred between the District, Village, U.S. Army Corps of Engineers, Illinois Department of Natural Resources/Office of Water Resources (IDNR/OWR), and FPDCC since the flooding of April 18-19, 2013. During discussions with IDNR/OWR, it was indicated compensatory storage would not be required for improvements to the levee as the levee is located outside the regulatory floodway.
District staff has since reexamined the economic feasibility of DPR-14D by removing the cost for the compensatory storage and considering other factors described below. The construction cost for improving the levee is approximately $10.0 million, yielding a benefit-to-cost ratio of 0.86. Not included in the benefits are the potential economic and safety issues that could arise should the ComEd substation located east of Forest View become inoperable due to flooding. Floodwater did reach the ComEd substation during the April 18-19 event, but was mitigated substantially by efforts of the Village. The ComEd substation service area includes Midway Airport and the Stickney Water Reclamation Plant (SWRP). There is also potential flood water could reach SWRP. The Engineering Department believes these factors justify initiating preliminary engineering for this project.
It is therefore requested that the Executive Director recommend the Board of Commissioners approve initiation of design of DPR-14D to be funded under the Stormwater Management Fund. Upon approval of this request, the Engineering Department will initiate selection of a consultant to perform the necessary work.
Requested, Catherine A. O'Connor, WSS:JPM
Recommended, David St. Pierre, Executive Director
Respectfully Submitted, Michael A. Alvarez, Chairman Committee on Stormwater Management
Disposition of this agenda item will be documented in the official Regular Board Meeting Minutes of the Board of Commissioners for June 20, 2013
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