IOWA RESERVOIR REPORT

Last Updated: March 13, 2026

Iowa's network of dams and reservoirs plays a crucial role in managing water resources, yet varying conditions can affect their storage levels and impact the surrounding areas. Based on the latest observations, most of the state's reservoirs show gage heights close to average seasonal values. For instance, the Clear Lake at Clear Lake, Black Hawk Lake at Lake View, Lake Panorama at Panora, and Spirit Lake near Orleans are recording levels that are slightly lower than their averages, signaling a manageable situation. However, West Okoboji Lake at Lakeside Lab near Milford is experiencing noticeably low water levels, which could be an indicator of reduced inflow or increased water usage. In contrast, Corydon Lake's streamflow is significantly above average, possibly due to recent precipitation events or snowmelt contributing to runoff.

The abnormal conditions observed at specific dams such as the reduced gage height in West Okoboji Lake and elevated streamflow in Corydon Lake warrant further attention. West Okoboji Lake’s lower level could be a result of lower snowpack melting or decreased rainfall contributing to the watershed, which may affect recreational activities or local water supply. On the other hand, the increased flow at Corydon Lake could be due to sudden snowmelt or heavy rains, potentially posing a risk of flooding downstream if trends continue. It's critical for local management authorities to monitor these changes to anticipate and mitigate potential adverse impacts, including adjusting water releases or preparing for flood conditions. Cross-referencing with multiple data sources, including local weather stations and hydrological forecasts, would help confirm these observations and enable more accurate predictions for these water bodies in Iowa.

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.