Submitted to: Soil and Water Conservation Society
Publication Type: Abstract Only
Publication Acceptance Date: July 17, 2002
Publication Date: October 1, 2002
Citation: Tomer, M.D., James, D.E. 2002. Optimizing placement of practices to intercept nutrients in a tiled-drained agricultural watershed [abstract]. Soil and Water Conservation Society. 57:296
Nutrients carried from agricultural lands in surface waters and tile drains are raising significant environmental concerns. While in-field agricultural practices can be implemented to reduce these nutrient losses, complementary practices that enhance nutrient-removal processes within riparian ecosystems are also being advocated and supported using public subsidies. Riparian buffers and constructed wetlands are the dominant examples of these practices; riparian buffers can intercept surface water runoff, but constructed wetlands are needed to intercept and treat tile drainage. Can the placement of these practices be optimized within a given watershed? We are developing a strategy to identify stream reaches where these practices can be most effective at treating flows. The Tipton Creek watershed, a 20,000 ha catchment in north-central Iowa, is being used as a case study. Hydrologic modeling of digital elevation data is helping us to identify where the best opportunities to intercept surface runoff waters exist along the channel network. In carrying out the analysis, stream reaches must be classified so that buffer placement is prioritized for stream reaches where overland flow is likely to enter the stream as distributed flows. Also, we are identifying those sites that should meet established criteria for selection of sites for CREP (Conservation Reserve Enhancement Program) wetlands in Iowa, which are aimed to treat tile-drainage waters. Results are being presented to local groups and agency personnel, who will help recruit landowners to establish these practices in sensitive areas for improved water quality.