West Riverside Energy Center: How Nature Based Stormwater Solutions Led to Envision Platinum Verification

To transition toward cleaner energy production, Alliant Energy embarked on the development of the most environmentally friendly, natural gas-fired energy facility in the Midwest. The newly constructed West Riverside Energy Center (WREC) provides enough power to support more than 550,000 homes in the region. Located on a 90-acre site in Beloit, Wisconsin, the WREC became the first Envision Platinum-verified project in Wisconsin by following the Institute for Sustainable Infrastructure's framework for assessing sustainability, resiliency, and equity in infrastructure. The planning, design, and construction of the WREC leveraged Nature-Based Solutions to restore natural systems on the site. The project restored nearly 67 acres of natural environment surrounding the facility through the conversion of agricultural cropland to native prairie grasses and wildflowers, creating new habitat and improving habitat connectivity. In addition to the landscape restoration, the project was designed to mimic pre-development hydrologic conditions. Innovative techniques, including stormwater harvesting and re-use for process water, stormwater pond retrofits, and treatment train including rain gardens and bioswales helped the project achieve the Restorative designation for stormwater management, becoming the first Envision-certified project to reach this performance standard, in which stormwater management was not intended as the primary purpose of the project. The WREC manages nearly 170 acres of stormwater runoff through best management practices (BMPs) that include vegetated swales, a 1-acre infiltration basin with engineered subsurface media, 5,000 gallon stormwater harvest and re-use cistern, and land use conversion. HydroCAD and WinSLAMM were used to model project performance, indicating that event-based peak flow rates would decrease between 14% to 20%, and the property would reduce stormwater runoff by 65,000 CF on an average annual basis. WinSLAMM estimates that total suspended solids (TSS) will be reduced by 84% on an average annual basis as a result of the stormwater design. The design achieved ISI's Restorative designation for stormwater management by maintaining or improving pre-developed hydrologic conditions and retaining or repurposing more than 100% of the pre-development infiltration capacity of the site. These stormwater solutions complemented WREC's One-Water approach for the site. The facility minimized water consumption by implementing unique water treatment solutions, re-using water within the facility, and treating wastewater prior to discharge to the Rock River. A process water pre-treatment system allows for 8 to 10 cycles of process water concentration, compared to an industry typical standard of 4 to 5 cycles of concentration from untreated well water. The team also utilized a land management approach outside of the main building as part of a Phosphorus Trade Agreement to meet or exceed Wisconsin's nutrient discharge requirements. Co-benefits associated with WREC development and sustainable water management include a new multi-modal trail connection to a 12-mile walking, hiking, and biking trail. A 4 MW solar field was constructed to provide the generating station with the ability to quickly and efficiently adjust for power demands in real time. An energy lab provides an interactive forum for public education to communicate the benefits of the prairie restoration and renewable energy production. By following the Institute of Sustainable Infrastructure's sustainability framework, the WREC was completed under budget, and the facility was online in time for increased summer power demand. Successful planning, design, and construction of the WREC serves as a model for Nature-Based Solutions and sustainable water management in the Midwest. This presentation focuses on project goals, regulatory and design criteria management, modeling, design, and results. By implementing a one-water approach and nature-based solutions, this award-winning project incorporated sustainable water and environmental practices to contribute toward Envision Platinum verification.