Research buoys deployed in central Iowa reservoirs for joint ISU and DNR study

The Iowa Department of Natural Resources (DNR) and Iowa State University are partnering to better understand oxygen and temperature dynamics in 20 central Iowa reservoirs. 

The ongoing research includes monitoring oxygen and temperature variations throughout the open water periods of 2026 and 2027. Both oxygen and temperature are vital for suitable fish habitat and impact nutrient cycling within reservoirs.

Buoys with water temperature and dissolved oxygen loggers are deployed at Big Creek, Hickory Grove, and Rock Creek lakes. Lake users are asked to avoid disturbing the buoys while out using the lakes, be vigilant while boating, and follow posted speed restrictions.

Additional buoys at Big Creek Lake in Polk County are part of the research project tracking the movement of fish in the upper portion of the lake. This spring a combined total of 65 walleye, muskellunge, largemouth bass, channel catfish, freshwater drum and common carp were tagged to detect what areas of the lake fish are using as habitat conditions change throughout the year. Tagged fish have a small incision and green sutures. Anyone who retrieves one of these tags from a legally harvested fish is encouraged to report it to the local Iowa DNR fisheries management staff.

This research will help define the habitat conditions that can cause harmful algal blooms, impact water quality, and influence fish populations in central Iowa reservoirs. Results from this research will help guide future lake restoration efforts and fisheries management strategies across central Iowa.