Land 2014, 3, 206-238; doi:10.3390/land3010206 OPEN ACCESS land ISSN 2073-445X www.mdpi.com/journal/land/ Article Restoration of Prairie Hydrology at the Watershed Scale: Two Decades of Progress at Neal Smith National Wildlife Refuge, Iowa Keith E. Schilling 1,* and Pauline Drobney 2 1 Iowa Geological Survey, University of Iowa, 109 Trowbridge Hall, Iowa City, IA 52242, USA 2 Neal Smith National Wildlife Refuge, US Fish and Wildlife Service, P.O. Box 399, Prairie City, IA 50228, USA; E-Mail:
[email protected] * Author to whom correspondence should be addressed: E-Mail:
[email protected]; Tel.: 1-319-335-1575. Received: 19 December 2013; in revised form: 19 February 2014 / Accepted: 20 February 2014 / Published: 6 March 2014 Abstract: Tallgrass prairie once occupied 67.6 million hectares in the North American Midwest but less than 0.1% remains today. Consisting of more than 2200 ha, Neal Smith National Wildlife Refuge (NSNWR) was established by the US Fish and Wildlife Service in the 5217 ha Walnut Creek watershed in Jasper County, Iowa. Large tracts of land are being converted from row crop agriculture to native prairie and savanna with the goal to restore the landscape to a semblance of the condition that existed prior to Euro-American settlement. Understanding hydrologic processes at the watershed scale has been a focus of research at NSNWR for nearly two decades and the purpose of this paper is to integrate research results from monitoring projects to assess the progress made towards restoring five key hydrologic components: the water balance, stream network, streamflow hydrograph, groundwater levels and water quality.