Development of Error Parameters for Infiltrometers

Infiltration rates are critical to hydrologists' understanding of the behavior of a soil during rainfall events, as well as for predictive estimates of runoff potential. Current infiltration studies rarely account for inherent procedural error associated with this technique due to the large numbers of samples required. The objective of this study is to establish error parameters for use with double-ringed infiltrometers. In Fall of 2007 and 2008, infiltration rates of soils determined to be statistically similar on the basis of bulk density, texture (by class), slope, and vegetation were measured and analyzed. The soils' equilibrium infiltration rates (EIRs) were used to develop error parameters for standard use of double-ringed infiltrometers. The EIRs of soils of the same textural class, as well as statistically similar bulk densities were compared, and a 95% confidence interval was established. The hypothesis is that EIRs of soils of like textural class, vegetation cover, slope, and statistically similar bulk densities will fall within one standard deviation of the mean. Additional infiltrations were then completed to assess the viability of using the determined confidence interval as a predictor range of the EIRs of similar soils.