IOWA RESERVOIR REPORT

Last Updated: December 29, 2025

In Iowa, the latest observations of major dams and reservoirs indicate a mix of normal and abnormal conditions in water storage levels. Clear Lake, Black Hawk Lake, Lake Panorama, Spirit Lake, and West Okoboji Lake are all reporting gage heights marginally lower than their respective averages, signaling a slight decrease in water levels, which could indicate a period of reduced precipitation or increased water usage. The most significant anomaly comes from Corydon Lake, where the streamflow is substantially higher than average, suggesting potential issues such as recent heavy rainfall events or snowmelt. Conversely, Rathbun Lake is showing a minor decrease in gage height, displaying a trend similar to the other lakes but with less disparity from its average.

The reported drop in gage heights across several reservoirs, while not drastic, might be an early indicator of a drier season or modified management strategies affecting water retention. Specifically, Clear Lake, Black Hawk Lake, and West Okoboji Lake, known for their recreational significance, are experiencing slight reductions in water levels, which could impact local water activities if the trend continues. The notable increase in streamflow at Corydon Lake demands attention as it could be related to upstream factors such as excessive rainfall or snowpack melt, which may have implications for flood risk management. These observations, subject to verification against multiple data sources, reflect the dynamic nature of reservoir and dam management in Iowa, highlighting the importance of ongoing monitoring and adaptive water resource strategies to address these fluctuating conditions.

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.