PARENT SESSION
Organized Oral Session 18: Ecological guidelines for management of water quantity and quality in agricultural landscapes
Organizer(s): L Ryszkowski and R Lowrance
Tuesday, August 9, 8:00 AM - 11:30 AM, Meeting Room 516 C, Level 5, Palais des congrès de Montréal
Effects of riparian vegetation and management on hydrology and water quality in agricultural watersheds of central Iowa, U.S.A.
Isenhart, Thomas*,1, Schultz, Richard1, Simpkins, William1, Schilling, Keith2, 1 Iowa State University, Ames, IA2 Iowa Department of Natural Resources, Iowa City, IA
ABSTRACT- The glaciated midwestern U.S.A. contains a unique combination of geology, hydrology, and soils that provides one of the most productive agricultural systems on the Earth. Exploitation of these resources has resulted in pervasive intensively managed landscapes characterized by extensive modifications to flow paths, fluxes, and storage in terrestrial water resources. The physical, chemical, and biological modifications to the region have also generated a variety of unintended environmental problems, including degradation of local and downstream water quality. Our work has focused on assessing the efficacy of perennial plant-based conservation practices to complement in-field best management practices. The overarching goal is to achieve a better understanding of how to maintain the productive capacities of this region while improving the management of its abundant water resources. Work is being conducted on the Bear Creek and Walnut Creek Watersheds in Central Iowa, U.S.A. The Bear Creek Watershed Project has focused on riparian management, with more than 11 km of riparian buffers established since 1990, providing a chronosequence ranging from two years to 15 years since establishment. The Walnut Creek studies were initiated in 1995 at the Neal Smith National Wildlife Refuge and monitors changes in water quantity and quality associated with a large-scale conversion of row crop agriculture to native vegetation. To date, over 20% of the watershed acres have been converted to prairie. This research has shown that proper placement and management of riparian and upland vegetation will reduce diffuse pollution transport to surface and groundwaters, but that such benefit is highly dependent upon the hydrogeologic setting and the composition and age of the vegetation.
Key words: water quality, riparian, hydrology, vegetation