Academic Resources for Watershed Modeling

In addition to the technical resources supplied to assist in the use and understanding of each model, numerous academic studies and reports have been completed on the effectiveness and applications of various watershed models. A few of these academic resources are summarized below:

Heartland Regional wAter Quality Monitoring Group

While this site was also featured as a SWAT-specific resource, its utility in deciding which model to use and technical assistance on how to use them makes it worth repeating. The monitoring group has developed several modeling-education webcasts, all of which are available HERE. Models covered include SWAT, HSPF, and APEX, among others.

The Science of Targeting within Landscapes

Walter, T. et al. 2007. The Science of Targeting within Landscapes and Watersheds to Improve Conservation Effectiveness. In Managing Agricultural Landscapes.

This piece provides an overview of the current status of targeting efforts. It explains the scientific justification for targeting and provides an overview of current technological tools that are enhancing the opportunities for targeting at multiple spatial scales. It then provides examples of applications of targeting for both conservation and water quality. Water quality targeting techniques include buffer placement to enhance effectiveness, identification and management of hydrologically sensitive areas, and targeting based on soil test of phosphorus levels. Their conclusions are four-fold: First, targeting approaches are increasingly refined as scientific understanding of landscapes improves and technology advances. Second, what to target and at what degree of precision should vary based on ones management objectives. Third, issues of scale are important. The authors explain targeting must “focus at scales where the scales of the system, management practices, and objectives coincide” (81). And last, while the emphasis is on scientific efforts, the economic, social and political context within which scientific efforts are applied are essential to their application.

Targeting of Watershed management practices for water quality protection

Wortmann, C.S. et al. 2008. Targeting of Watershed Management Practices for Water Quality Protection. University of Nebraska-Licoln, Heartland Regional Water Coordination Initiative.

This report provides an overview of essential considerations in targeting as well as overview on tools, technologies and resources that contribute towards an effective targeting program. This includes an introduction to the computer mapping and analysis tools available to land managers. While much of the information is foundational and general, their recognition of the importance of local knowledge within priority setting is of note, especially in light of much of the academic literature that focuses almost exclusively on scientific and/or economic dimensions of targeting.

Strategic Targeting of Cropland Management using watershed modeling

Tuppad, P., K. Douglas-Mankin, & K. McVay. 2010, December. Strategic Targeting of Cropland Management using Watershed Modeling. Agricultural Engineering International: CIGR Journal 12(3): 13-24.

The authors study the sediment, N and P reduction potential of targeting vs. random selection of BMP implementation in the Smokey Hill River Watershed in Kansas using a SWAT (Soil and Water Assessment Tool) model. They not only find that targeting is more effective than random (simulating voluntary) enrollment, but also that the reduction per acre is highest in the earliest subbasin BMP adoption, thus the environmental benefits diminish as more land is converted to BMPs. This implies that targeting is most effective both in terms of environmental benefit and cost-effectiveness in early implementation phases, and that voluntary enrollment can be employed later on. In addition to the results of the study, this article provides valuable information on the use and application of spatial modeling in general and the SWAT model in particular for spatial targeting.

Integrating watershed- and farm-scale modeling framework for targeting of CSAs

Ghebremichael, L., T. Veith and J. Hamlett. 2012. Integrated watershed- and farm-scale modeling framework for targeting critical source areas while maintaining farm economic viability. Journal of Environmental Management 114: 381-394.

The authors recognize the significant advancements in modeling capabilities at identifying what they call critical source areas (CSAs), or portions of the watershed that contribute disproportionately high pollutant levels, and are thus prime for targeting. They find current models, however, to have limited applications for four reasons: (1) complex models are not easily interpreted, directly or in simplified form, by conservation specialists, extension personnel, landowners, ect; (2) scalar mismatch between the hydrologic scale CSAs and BMPs are evaluated on and the field scale of implementation; (3) lack of information on specific environmental management recommendations and there on-field implementation and requirements therein (i.e. labor); and (4) models do not account for farm-system components such as labor and resources and external factors such as market indicators. They thus develop a model which incorporates both the SWAT model to develop improved geospatial information and the IFSM farm-scale model to factor in environmental and economic factors at the field-scale. When applied to two different watersheds, the models found that (1) CSA modeling is most effective when used to find a range of attributes indicative of disproportionality than looking for specific fields due to yearly fluctuations and data availability and (2) that decreasing P loss at a watershed scale did not necessarily increase farm profitability or P balances. This second conclusion indicates that, in such cases, farm management strategies need to be evaluated to make more efficient nutrient management decision.