ABSTRACT:
Predictions of sediment yield with the Universal Soil loss equation (USLE) on mined and reclaimed areas provide average estimates of soil loss on an annual or design-storm basis. Such estimates are used to implement conservation practices and design diversions and runoff holding ponds. The average estimate may not be the best if the distribution of soil loss over an area does not follow the normal or Gaussian distribution function and if chosen USLE parameters do not correspond to actual values. As an alternative, we suggest computing the distribution of subareas that have a given probability of exceeding a preselected soil loss tolerance level. Computations are illustrated for a site in Pennsylvania using a novel Probability Kriging algorithm. Results show the distribution of expected soil loss values, quantiles of the distribution, and the probability of exceeding a given tolerance level. The suggested approach could make it easier to select critical areas in need of conservation. The output also can be tested for chances of a judgment error. The approach is illustrated here for erosion estimates, but can be applied equally well to nonpoint-source pollution problems.
Footnotes
A. S. Rogowski is a soil scientist with the Agricultural Research Service, Northeast Watershed Research Center, U.S. Department of Agriculture, 110 Research Building A, University Park, Pennsylvania 16802; B. E. Weinrich is an assistant professor of mathematics, California University of Pennsylvania, California, Pennsylvania 15419; and R. M. Khanbilvardi is an associate professor of civil engineering, City University of New York, New York, New York 10031. This paper is a contribution from the Agricultural Research Service, U.S. Department of Agriculture, in cooperation with the Pennsylvania Agricultural Experiment Station, The Pennsylvania State University, University Park, 16802.
- Copyright 1990 by the Soil and Water Conservation Society
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