Adrienne Nemura (Michigan) and Rishab Mahajan (Illinois) delivered a presentation entitled "Mixing Zones – How can they be utilized?" to the DuPage River Salt Creek Workgroup on February 1, 2018.

The presentation covered Clean Water Act regulations regarding mixing zones and a case study on the use of a mixing zone study to demonstrate compliance with existing ammonia criteria.

The meeting included an update from the Illinois Environmental Protection Agency (Illinois EPA) and participants discussed progress on conforming to several special conditions in their National Pollutant Discharge Elimination System (NPDES) discharge permits. These conditions include evaluation of phosphorus-removal technologies at publicly owned treatment works (POTWs), and the use of mixing zone models to establish permit limits for toxic pollutants such as ammonia and chlorides.

Adrienne Nemura is a Senior Principal Water Resources Engineer based in Michigan with more than 30 years of experience focused on helping clients identify cost-effective and sustainable solutions to meet their water quality goals. She has worked for more than 40 cities and wastewater utilities and also state and federal regulatory agencies, industrial facilities, airports, attorneys, consulting firms, non-profit organizations, and trade associations.

Rishab Mahajan is a water resources engineer involved in hydrodynamic, sediment transport and water quality modeling with a focus on regulatory permits and requirements, stormwater management, surface water system assessments, total maximum daily load (TMDL) development and implementation, and nutrient criteria limit development. His experience includes the development and calibration of hydrodynamic, sediment transport and water quality models, including one-dimensional (1-D), 2-D, and 3-D models. Rishab specializes in geographic information system (GIS) analysis and programming in Java, Visual Basic, and database management.

The East & West Branches of the DuPage River and Salt Creek are located in Northeastern Illinois, including portions of Cook, DuPage, and Will Counties. In response to concerns about the East & West Branch DuPage River TMDLs and the Salt Creek TMDL, a local group of communities, POTWs, and environmental organizations came together to form the DuPage River Salt Creek Workgroup (DRSCW). DRSCW aims to better determine the stressors to the aquatic systems through a long-term water quality monitoring program and develop and implement viable remediation projects. Because of the similarities of water quality issues, development patterns and multiple agency/organizational overlap this group will address both watersheds simultaneously.

The Illinois General Assembly was the first state legislature in the nation to adopt a comprehensive Environmental Protection Act. It was signed into law by Governor Richard Ogilvie and became effective on July 1, 1970. As a part of that act, the Illinois EPA was created.

The mission of the Illinois EPA is to safeguard environmental quality, consistent with the social and economic needs of the State, so as to protect health, welfare, property and the quality of life.

Illinois EPA works to safeguard the state's natural resources from pollution to provide a healthy environment for its citizens. By partnering with businesses, local governments and citizens, Illinois EPA is dedicated to continued protection of Illinois' air, water, and land resources.

More Information

Learn more about the DuPage River Salt Creek Workgroup: http://drscw.org/.
Read the presentation PowerPoint: http://drscw.org/wp/wp-content/uploads/2018/02/6_Geosyntec.pdf.
For consultation regarding Mixing Zones, contact Adrienne Nemura at This email address is being protected from spambots. You need JavaScript enabled to view it. or Rishab Mahajan at This email address is being protected from spambots. You need JavaScript enabled to view it.. 
Learn more about Adrienne at: https://www.geosyntec.com/people/adrienne-nemura
Learn more about Rishab at: https://www.linkedin.com/in/rishabmahajan/