R2026-134 - Resolution Authorizing a Memorandum of Understanding for Development of a Regional Integrated Plan for Wastewater and Stormwater for Decatur, Illinois

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MOU for Regional Integrated Plan for Decatur, Illinois April 10,2026 Page 2 of 6 The results of the study concluded the high influent concentrations are due to the nationally and internationally significant grain milling operations which discharge over 90%of the TP load entering the WRRF. The study further supports that the effluent from the WRRF is estimated to contribute approximately 70 percent of the total TP load to the river. Modeling conducted by SDD's consultants projects that meeting an effluent limit of 1.0 mg/L will reduce the WRRF's contribution to 11 percent of the total TP load to the river and substantially improve water quality (reduce chlorophyll-a levels and number of days with high dissolved oxygen levels). SDD submitted the NARP to the Illinois EPA in December 2024. The NARP outlines significant upgrades at SDD's WRRF required to reduce TP contributions to the Sangamon River and comply with the permitted 1.0 mg/L limit. IU's will also be required to limit the amount of TP that they send to SDD to meet the limit. The capital costs of these upgrades at SDD and the IUs are significant. As discussed in the NARP, there are uncertainties regarding the response of the river to the reduced phosphorus loads, warranting revisiting the assumptions in the river modeling. Finally,the testing done by third party consultants demonstrated that due to the specific nature of the speciation of the TP, at this time, the reductions needed at the WRRF to eliminate the phosphorus-related impairments are technically infeasible. To address this issue SDD included development of a Regional Integrated Plan for wastewater and stormwater in accordance with US EPA's Integrated Municipal Stormwater and Wastewater Planning Approach Framework(US EPA, 2012)and the Clean Water Act. The Regional Integrated Plan will provide significant benefits to the Parties. These include planning for capital projects such as, but not limited to, those needed for new or revised water quality standards for wastewater, stormwater, and drinking water; coordinated planning for combined sewer overflow and sanitary sewer overflow mitigation; coordinated water supply planning including any needed upgrades to the City's drinking water plant; and coordinated planning on continued measures to improve local water quality including stream restoration and bank stabilization. This allows the Parties to collaborate on accommodating planned growth with economic development, enhancing regional benefits, and furthering sustainability initiatives. Industrial users are significant users of water and contributors to wastewater. While they are not direct parties to this agreement they may participate in individual projects or join the MOU in the future. This MOU outlines the framework for these efforts and the roles of each Party involved. Objectives The primary objectives of this MOU are to: • Develop and implement a Regional Integrated Plan with SDD and the City of Decatur. Additional parties with water-related needs or improvements can be added as the projects become evident.