IOWA RESERVOIR REPORT

Last Updated: December 24, 2025

In a recent review of Iowa's dam and reservoir conditions, observations reveal that water storage levels are close to average for this time of year, with minor deviations. For instance, Clear Lake at Clear Lake is reported to have a gage height of 4 feet against an average of 4.53 feet, and Black Hawk Lake at Lake View shows a small decrease with a current gage height of 7 feet compared to the usual 7.15 feet. Similarly, Lake Panorama at Panora and Spirit Lake near Orleans are slightly below their average gage heights of 45.41 feet and 14.03 feet, respectively, with current measurements at 45 and 14 feet. West Okoboji Lake near Milford is also below its average of 4.17 feet, standing at 3 feet. Rathbun Lake near Rathbun closely follows its average mark, sitting at a gage height of 904 feet against an average of 906.49 feet. These trends suggest that most major dams are within normal operating ranges for the season.

However, Corydon Lake displays an abnormal condition with a significant increase in streamflow, currently at 5 cubic feet per second (ft³/s), over twice the average of 1.96 ft³/s. This spike may indicate runoff events, possibly due to precipitation or snowmelt, which could affect downstream river conditions and local ecosystems. Cross-referencing this data with the Iowa DNR Fishing Report and agricultural publications such as the High Plains Journal, which often indicate regional weather events and water usage, might provide additional insights into the causes of these abnormal streamflow conditions. Overall, the water storage systems in Iowa are stable, but stakeholders should monitor the situation at Corydon Lake closely for any potential impacts of the increased water flow.

Iowa has several major reservoirs, including Coralville Lake, Rathbun Lake, and Saylorville Lake. These reservoirs are primarily fed by the Iowa River, Des Moines River, and Chariton River, respectively. Snowpack and mountains are not significant factors in Iowa's hydrology. Coralville Lake has experienced record high water levels in the past, with flooding in 2008 and 2013 causing significant damage. Drought conditions have also affected Iowa's reservoirs, with Saylorville Lake reaching record low levels in 2012. Seasonal trends in Iowa typically involve greater precipitation in the spring and summer months, leading to higher reservoir levels. However, prolonged periods of drought can disrupt this pattern. Overall, reservoirs and dams serve an important role in managing Iowa's water resources and mitigating the risk of floods and droughts.

Iowa has several major reservoirs, including Coralville Lake, Rathbun Lake, and Saylorville Lake. These reservoirs are primarily fed by the Iowa River, Des Moines River, and Chariton River, respectively. Snowpack and mountains are not significant factors in Iowa's hydrology. Coralville Lake has experienced record high water levels in the past, with flooding in 2008 and 2013 causing significant damage. Drought conditions have also affected Iowa's reservoirs, with Saylorville Lake reaching record low levels in 2012. Seasonal trends in Iowa typically involve greater precipitation in the spring and summer months, leading to higher reservoir levels. However, prolonged periods of drought can disrupt this pattern. Overall, reservoirs and dams serve an important role in managing Iowa's water resources and mitigating the risk of floods and droughts.