Attenuating Excessive Sediment and Loss of Biotic Habitat in an Intensively Managed Midwestern Agricultural Watershed

Portions of the 700 km² Elm Creek watershed in southern Minnesota have undergone watershed and channel improvements over the past decade to mitigate turbidity and biota impairment. Increased row cropping, artificial drainage, channel modifications and precipitation have cumulatively contributed to impairment and channel instability. Uplands that were once a prairie pothole landscape are now predominately drained corn-soybean fields, providing little hydrologic storage and sediment attenuation during peak runoff. Riparian degradation and channel discontinuity characterize much of lower Elm Creek. Wetlands have been restored in the upper watershed to reduce runoff and nutrient loading from croplands. Downstream, a 750 meter riparian corridor of Elm Creek was restored and the channel improved by oxbow reconnection, bluff and streambank protection. Monitoring will document erosion and sediment deposition within the reach and Index of Biotic Integrity (IBI) data will be collected to characterize fish and invertebrate communities in the stream.