An approach to estimating uncertainties in modeling transport of solutes through soils

Abstract

The objective of this research was to determine the effect of uncertainty in model parameters and rainfall on uncertainty of model response and the impact of these uncertainties on sample size requirements for simulating solute transport through soils. The research was designed to demonstrate a methodology with general applicability. The approach should help one understand the model being used and the uncertainty in model response. The magnitude of uncertainty in the estimated solute transport resulting from parameter variability was found comparable to that resulting from rainfall variability. The combined parameter and rainfall variabilities appear to magnify overall uncertainty in estimated solute transport. The results of uncertainty analysis, in conjunction with the sampling theory, were used todetermine the minimum number of random soil samples required to achieve a given degree of certainty in the estimated solute transport. Increasing soil sample size offers diminishing return in improving estimated solute transport because of natural rainfall variability.