Results From The Farm Behaviour Component Of The Integrated Economic Hydrologic Model For The Watershed Evaluation Of The Beneficial Management Practices Program PDF Download

Abstract: Conservation management practices are considered one of the best answers to escalating water quality deterioration by nonpoint source pollution. Integrated watershed economic model (IWEM) offers a multidisciplinary framework by addressing both the biophysical and the economic (cost and benefit) aspects of water quality improvement. An IWEM would have: a watershed model, an economic model, and an integration tool. Components of IWEM were translated into three essays of the dissertation and applied to the Upper Big Walnut Creek (UBWC) watershed in central. The modeling of the UBWC watershed was performed in the first essay. Soil and Water Assessment Tool (SWAT) was used to predict the nutrient export associated with land management practices. A new integrated calibration procedure was introduced for the calibration and validation of the UBWC watershed model. The predicted flow for daily, monthly and annual time scales were not statistically different from the measured values. Moreover, the predicted crop yield was also not statistically different from the reported values. Nitrate fluxes, calibrated using the field measured values at the two paired sub-watersheds, predicted nitrate loading was statistically not different from the measured values. The uncertainty analysis showed that the model predicted flow and nitrate load was with the lowest uncertainty. Recreational value of water quality improvement was estimated in second essay by using a combined revealed and stated preference method with baseline dependence and unobserved heterogeneity modeling. A mailed survey method was used to collect data, in which 1400 registered anglers and licensed boaters in 5 surrounding counties of the watershed were selected for the study. The baseline average number of trips was 2.35, which was reduced to 1.72 with more information about pollution level in the watershed. However, water quality improvement would increase the number of trips to 2.78. The average annual consumer surplus was $52.23, $28.09 and $91.11 for baseline, trip with more pollution information and trip with improved water quality conditions, respectively. In the third essay, dynamic programming was used for integrating the watershed and economic models presented in the above two essays. The watershed modeling results from essay 1 and the benefit estimates from essay 2 were used to specify the objective and transition functions of the dynamic program. The watershed model was used to simulate the baseline and crop rotation and conservation technology-specific production functions. Two sets of conservation technologies were developed for the watershed. One with cover cropping, conservation tillage and vegetative buffer stripes and the other with split nitrogen fertilizer application, cover cropping, conservation tillage and vegetative buffer stripes. The analysis revealed that under no restriction on pollution loading, farmers would apply a maximum of 170.51kg/ha of N and the value function would be $7950 under C-S-W rotation. The fertilizer application rate was reduced to 103 kg/ha when cost of pollution was internalized in profit. Within the crop-technology combinations, split-N application, conservation tillage, cover crop showed the lowest pollution load to the reservoir along with higher value function.