Watershed Restoration: Principles and Practices

Chapter 19: Watershed Restoration and Agricultural Practices in the Midwest: Bear Creek of Iowa

T. M. Isenhart, R. C. Schultz, and J. P. Colletti

doi: https://doi.org/10.47886/9781888569049.ch19

The Western Corn Belt Plains ecoregion, which covers most of Iowa and parts of surrounding states, can be characterized as extensive cropland on level to gently rolling dissected glacial till plains, hilly loess plains, and morainal hills with broad smooth ridgetops (Griffith et al. 1994). This landscape has been largely converted to agricultural uses; more than 80% of most counties of the ecoregion are dedicated to corn, soybeans, and forage for livestock (Burkhart et al. 1994). Nearly two-thirds of the native hardwood forests have been converted to row crop agriculture or pasture. Modification of the local and regional hydrology has been an essential part of this land use conversion. Annual cultivation has reduced soil quality, lowering rates of infiltration and increasing surface runoff. Creation of extensive networks of subsurface tile drains, excavation of surface drainage ditches, and channelization of many perennial streams has facilitated the conversion of nearly all prairie and wetland acreage to agricultural uses and contributed to many off-site, downstream problems of water flow and quality.