Polk County Launches Central Iowa Source Water Research Assessment

Historical Background of the Confluence of Two Rivers:
The Fort Des Moines military post was established in 1834 at the confluence of the Des Moines and Raccoon Rivers. To this day, the two rivers and their tributaries play a significant role in central Iowa’s local economy, culture, recreation community and overall identity. The rivers are the primary source of drinking water for over one-half million people. The confluence of the Des Moines and Raccoon rivers lies in the heart of our Capitol City, providing beautiful settings for parks, businesses and residential areas.

The base of the confluence is the most popular fishing location in the State of Iowa. Just inside the confluence lies Principal Park, home of the Triple A Iowa Cubs baseball team and the future site of a professional league soccer stadium. At the Northern edge of Polk County are two substantial water recreation destinations, Saylorville Reservoir and Big Creek Lake. Plans are currently underway to invest over $120 million for a network of water trails and water recreational opportunities throughout Central Iowa that will bring thousands of people to our waterways and shores.

Pollutants in the rivers, such as nutrients like phosphorus and nitrogen, bacteria from animal or human waste, sediment from erosion and harmful chemicals threaten the public health of our region and the ability of Des Moines Water Works to produce enough safe drinking water for one-fifth of Iowa’s population. Poor water quality in the rivers also threatens existing assets and future investments associated with recreation, property values and the beauty of our Capitol City.

Context for Central Iowa Source Water Research Assessment (CISWRA):
A significant body of research and data exists about the quality of the Des Moines and Raccoon Rivers. Studies and journal articles have been published by such esteemed research bodies as Iowa State University, the U.S. Army Corp of Engineers, United States Geological Survey, Iowa Geological Survey and IIHR Hydroscience and Engineering at the University of Iowa. Studies have found pollutants like phosphorus, turbidity, and algae blooms in the rivers. Additionally, the Science Assessment of the Iowa Nutrient Reduction Strategy, released to the public in 2013, contains credible data about the condition of Iowa’s waterways statewide.

Important research is ongoing in the two priority watersheds. Currently, a study is in progress which is a partnership between ICON Water Trails, Polk County Conservation, and the IIHR—Hydroscience and Engineering at the University of Iowa which will assess source water quality based upon several pollutants of concern.
Additionally, the National Cybersecurity and Infrastructure Agency—an arm of the Department of Homeland Security—is embarking on a comprehensive study of dangerous Harmful Algal Blooms (HABs) in the watersheds. HABs in Saylorville Reservoir, located upstream from Des Moines on the Des Moines River, result in annual beach advisories for unsightly, unpleasant algae blooms and the presence of algal toxins. Algal toxins in source water may be seen as a threat to drinking water security.

The Time is Right for CISWRA
CISWRA will build upon existing knowledge of Des Moines and Raccoon River water quality and the momentum around the new research. The project will result in a “state of the research” scientific assessment that summarizes important existing and emerging research, and identifies gaps in research that may warrant additional exploration. Additionally, CISWRA will produce recommendations for creating healthier rivers, as well as a pathway for residents and public engagement.

Experienced researchers from academic institutions, agencies and laboratories have been assembled to form the science advisory committee for the project. The science advisory committee will identify relevant research literature, reports, studies, data etc. to inform the assessment and recommendations.

The project will wrap up in early 2025, with issuance of three publications: “Final Scientific Assessment of Source Water Research” report; a white-paper that outlines clear recommendations and pathway for improved source water quality in the Raccoon and Des Moines Rivers; and a call to action containing actionable items for improving our rivers.

Polk County leaders hope that the findings of the assessment, the recommendations for water quality improvement, and the call to action to improve source water quality will ultimately have positive effects on public health, as well as recreational, environmental, and economic benefits.