Title: A farm-focused approach to improving watershed-level water quality Authors
|Ghebremichael, Lula -|
Submitted to: Proceedings of the World Environmental and Water Resources Congress Conference
Publication Type: Abstract Only
Publication Acceptance Date: January 31, 2013
Publication Date: N/A
Interpretive Summary: An interpretive summary is not required.
Technical Abstract: Agricultural nonpoint source pollution and corresponding mitigation management practices are typically evaluated for water quality effectiveness based on hydrologic boundaries. Often, multiple combinations of practices will adequately control the pollution, but at varying costs and farmer-acceptance levels. Thus, the effectiveness at the watershed-level is dependent on which feasible practices are actually selected and implemented at the farm- and field-levels. A framework for combining farm- and watershed-level models into a closed feedback loop is presented through application to a small agricultural watershed in northeastern United States. The Soil and Water Assessment Tool (SWAT) is used to simulate watershed- and field-level water quality and to identify critical source areas. Critical source areas are locations that are prone to both receiving and transporting high levels of pollutants, such as compacted, minimally covered areas where livestock congregate for feeding. A genetic algorithm and literature-reported reduction efficiencies for various Best Management Practices are combined with SWAT to optimally select and place combinations of management practices in order to maximally reduce phosphorus and nitrogen loadings to the watershed outlet. These solutions are considered for feasibility within the farm production system by applying the Integrated Farm Systems Model (IFSM) to major farm types within the watershed. Of particular interest are farms within the critical source areas, so that water quality pollution concerns are addressed while the farmers’ production systems are maintained or improved. Additional management practices and changes in farm operation are evaluated as needed to determine a workable solution at the farm-level. The farm-level solutions are combined and reevaluated at the watershed-level to verify that the water quality goals are being met. The comprehensive approach to designing watershed-level plans for managing and improving water resources increases the success level of the plans by incorporating the production needs of the farmers. Extended benefits include the ability to consider the impacts to the regional food supply system and to maximize desired ecosystem services. Additionally climate change scenarios can be incorporated within both the hydrological cycle and the agricultural system.