A systems approach to evaluate water quality oriented land management plans

A systems approach, utilizing a deterministic hydrologic simulation model and an optimization model, was developed to evaluate and optimize cropland Best Management Practices (BMPs). The approach consisted of using the Finite Element Storm Hydrograph Model (FESHM) to simulate runoff and sediment yield from a series of design storms with known return periods. The design storm simulations were the basis for sediment distributions representing unique cropland areas and management practices. The distributions were evaluated to obtain average annual sediment yields which were used as activity coefficients in a linear programming (LP) optimization model. The LP model selected the set of cropland management practices that minimized total sediment yield while meeting economic and agricultural production constraints.

A postoptimality analysis was performed on the optimal solution to examine the effects of variations in: (1) income levels representing subsidy, and (2) sediment coefficients. The optimal solution was found to be insensitive to reductions in income levels (representing subsidy) and extremely sensitive to changes in the sediment coefficients.

Limitations of the systems procedure models were discussed along with suggestions for improving the sediment coefficients and their practical usage.