Restored Oxbows Provide Multiple Benefits for Water and Wildlife

Historically, prairie streams of Iowa naturally meandered, creating cut-offs, or oxbows.  Oxbows reconnected to the stream during high-flow events, remained connected to the alluvial aquifer, and sustained adequate water year round. These oxbows provided habitat for many species of birds, amphibians, reptiles, and fishes, including the now endangered Topeka shiner (Notropis topeka). Anthropomorphic practices have altered stream hydrology and caused oxbows to fill in with sediment and disconnect from streams, and no longer provide the benefits they once did. Overall, this type of habitat has been greatly degraded or eliminated.

Here we hypothesize that oxbow restorations provide important habitat for many species, improve flood plain reconnection, and improve water quality.  Restoration consists of excavating post-settlement alluvial sediment, allowing oxbows hold water year-round. Fish species gain access to restored oxbows during high-flow events.  Field tile water intercepted by the oxbow provides nutrient sequestration, benefiting local water quality as well as the Gulf of Mexico Hypoxia. Tile water allows for temperature modulation and prevention of dry-out. Results of fish surveys (species and abundance), bird surveys, and water quality data will be presented that quantify benefits of these restorations.  We will also present strategies for effective implementation and funding for this conservation strategy.