TRANSMITTAL LETTER FOR BOARD MEETING OF MAY 1, 2008
COMMITTEE ON ENGINEERING
Mr. Richard Lanyon, General Superintendent
Title
Report on Calumet Treatment Wetlands Concept Development (Deferred from the April 17, 2008 Board Meeting)
Body
Dear Sir:
On April 19, 2007, the Board of Commissioners approved an additional $84,739.00 to the design agreement for Contract 07-846-3S, Treatment Wetlands at Lockport Powerhouse Marsh and Centennial Trail Marsh for V3 Companies of Illinois, Ltd. (V3). The additional consulting services consist of providing treatment wetland expertise and concept plans and costs to the District for a joint effort with the City of Chicago to develop wetlands in the Lake Calumet Basin. It was to be based on a 2004 concept study conducted for the District to investigate whether using wetlands in the Lake Calumet Basin could assist with nutrient removal for effluent from the Calumet WRP.
Attached is an exhibit showing a concept for a series of wetlands in the Lake Calumet Basin. A portion of the Calumet WRP discharge would be pumped to treatment wetlands constructed in Deadstick Pond, the Stony Island Solids Drying Area, Heron Pond, Indian Ridge Marsh (South), and Big Marsh, with discharge to Lake Calumet. All of the property is owned either by the District or the City of Chicago. The Stony Island portion of this plan is contingent upon a future decision by the District on the necessity of maintaining the Stony Island Solids Drying Area.
The proposed wetlands system would be able to treat up to possibly 50 mgd, (15 percent of the Calumet WRP effluent), and provide very modest levels of nutrient removal. Reductions in nitrate nitrogen from approximately 8.4 mg/l to 4.3 mg/l, and total phosphorus from approximately 2.8 mg/l to 2.5 mg/l, are possible. This would not negate the need for nutrient processes at the Calumet Treatment Plant should nutrient effluent limits be imposed.
The flow back to Lake Calumet would end up on the lake side of the O'Brien Locks, thus discharging into Lake Michigan. This would reduce the amount of discretionary diversion from Lake Michigan required to be allocated to the District, which would benefit the City of Chicago by providing additional lake water diversion rights for the City or other communities to avail themselves of. The engineer's preliminary estimate of probable construction cost for this project is $74,721,660.00.
The District held a meeting with regulatory agencies on March 17, 2008, to discuss the concept plan. Input from the U.S. Army Corps of Engineers, the U.S. Fish and Wildlife Service, the Illinois Environmental Protection Agency, the Illinois Department of Natural Resources, and other agencies will be necessary to see what regulatory issues and permits need to be addressed and obtained.
The proposed project would also provide environmental benefits. The City of Chicago's initiatives in the area, including the Calumet Open Space Reserve Plan, have placed emphasis on preserving and enhancing habitat for birds, fish, and other wildlife, as well as providing recreational opportunities for the community. Providing these added benefits would require the wetlands to be designed for more open water and plant diversity than would minimally be required otherwise. However, if this project is to move forward, buy-in by the City and the community is essential.
The City of Chicago Departments of Planning Development and Environment have been important participants in the planning process. The Mayor, Alderman Pope, and Alderman Beale have all been informed about the project. A further expansion of the project could possibly include the Conservation Area and Lake Calumet. The Illinois International Port District controls these areas; future discussions with the Port District are foreseen.
The conceptual design work is completed. In order to move the project forward, we will be requesting authority to enter into a new consultant agreement at a future Board meeting. This new agreement will permit development of the design to a 30 percent completion level, further refine the construction cost estimate, perform necessary environmental evaluations, and address contamination issues.
In parallel with the Lake Calumet wetlands evaluation, the Research and Development Department will shortly be initiating a study of the most appropriate technology for very low level nutrient removal at each of our treatment plants, and the costs for such technology, in the event that very stringent limits are imposed in the future. This study will proceed with the assistance of national experts through coordination with Illinois Institute of Technology, and will build upon the findings of a report recently released by the Water Environment Research Foundation on the same topic. For the Calumet plant, the study will include an evaluation of wetlands treatment working in conjunction with in-plant processes, to determine the best combination of in-plant technologies and wetlands design.
If further clarification is required, please advise the undersigned.
Respectfully Submitted, Joseph P. Sobanski, Chief Engineer, NV:AP:JMS
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