Lake Fork Reservoir Watershed, Texas << Research >> :: Results :: Papers Research Description   The second watershed study undertaken as part of the National Pilot Project, funded by EPA, was of the Lake Fork Reservoir watershed in Texas. The watershed covers 313,808 acres and includes dairy operations, beef production, pasture, and small amounts of crop land. Problems In the early 1990s, the Lake Fork Reservoir watershed was the subject of a hydrologic unit area project aimed at encouraging best management practices that would lead to reductions in agricultural pollutants in the watershed. About the same time, data collected by TCEQ identified elevated levels of orthophosphorus and low levels of dissolved oxygen in the reservoir itself. They identified nonpoint source pollution from agricultural activities as a likely cause. Researchers Edward Osei, Susan Neitsch, Phil Gassman, Jan McNitt, Ron Jones, Larry Hauck, Heather Jones Objectives After completing the first major application of CEEOT to the Bosque River watershed, the next step was to use CEEOT in a watershed with different environmental characteristics where dairying is carried out on a different scale, with different production practices. The Lake Fork Reservoir watershed was chosen for the next study. Researchers intended to capture a broad range of environmental and economic factors and also to test transferability of the modeling system. The table shows the key policy scenarios modeled for the watershed.   Main features of scenarios simulated for the watershed Pasture Management System Pasture Manure Nutrient Rate Hay Field Application Rate Other Specifications Open access grazing 1.5 times N 50% N, 50% Low P Status quo Open access grazing N 50% N, 50% Low P Assumes no commercial nitrogen or phosphorus fertilizer is applied to pastures. Open access grazing High P 50% N, 50% Low P Open access grazing Low P 50% N, 50% Low P Open access grazing High P Low P Open access grazing Low P Low P Intensive rotational grazing 1.2 times N 50% N, 50% Low P Cows rotate through paddocks, maximize forage intake, and eliminate denuded areas Grassed loafing lot 1.5 times N 50% N, 50% Low P Cows rotate through loafing lots, eliminates denuded areas Open access grazing, reduced phosphorus feed ration 1.5 times N 50% N, 50% Low P Reduced phosphorus feed decreases phosphorus in cow manure Open access grazing, reduced phosphorus feed ration Low P Low P Reduced phosphorus feed decreases phosphorus in cow manure Open access grazing, pasture edge filter strip 1.5 times N 50% N, 50% Low P Filter strips fenced to restrict cow access Column two, pasture manure nutrient rate, includes nutrients deposited by grazing livestock. The objective was to estimate both the water quality and economic impact of each of these scenarios. Methods Analysis of alternative practices for the Lake Fork Reservoir watershed was performed by first calibrating the CEEOT suite of models using data collected from the study area. Local stakeholders provided assistance and leadership in determining the types of scenarios or practices to simulate. The scenarios simulated for this watershed reflect the predominance of pasture-based livestock enterprises in the northeastern portion of Texas. After the scenarios were determined, the calibrated modeling system was applied using data collected in the study area. Data and assumptions used for simulations were based largely on local input, in addition to widely used environmental and economic databases.   << Research >> :: Results :: Papers

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2002 Texas Institute for Applied Environmental Research