Tradeoffs between agricultural interests and wetland ecological benefits int he Eramosa watershed
The purpose of this study is to evaluate the tradeoffs between agricultural returns, and sediment abatement and wildlife habitat ecological goals in the wetlands and croplands of the Eramosa River-Blue Springs Creek Watershed. The sediment abatement effects of wetland preservation and conservation tillage adoption in croplands were established using a GIS-based hydrologic model, incorporating the Universal Soil Loss Equation and a Sediment Delivery Model. Established wetland sediment abatement values ranged from 79.8 to 2,103.7, with an average of 582.2 tons per year, for the 56 selected wetlands. Cropland sediment abatement values ranged from 529.9 to 8,434.5, with an average of 3,072.9 tons per year, for the 22 agricultural subcatchments in the watershed. Wetland wildlife habitat benefits were established using a GIS-based Multi-Criteria Evaluation Model. The results ranged from 18.2 to 1514.6 points, with an average of 216.2. The results from the ecological models were combined with agricultural returns to create a series of economic, mathematical programming models. The models maximized agricultural returns from croplands and drained wetlands, subject to water quality and wildlife habitat constraints. The models revealed the tradeoffs between agricultural returns and ecological goals, along with the location and characteristics of wetlands and croplands suitable for each side of the tradeoff, under different constraint levels. Considering only wetland drainage decisions and a single ecological constraint, agricultural returns could increase greatly with relatively low amounts of wetland drainage. The addition of croplands allows higher sediment abatement goals to be reached at lower cost, or equal sediment abatement goals to be reached with higher returns. The inclusion of multiple ecological restraints limits potential agricultural returns. If multiple goals are considered and one cannot be decreased, then no agricultural returns can be realized.