Assessment of Methods for Interpolating Steady-State Infiltrability

The effect of interpolation method on the estimation of steady state infiltrability was evaluated. Four interpolation methods, namely, the inverse distance weighting method, punctual kriging with the assumption of a linear semi-variogram, quintic polynomial interpolation, and the method of minimum surface curvature, were evaluated. These methods were found to produce significantly different interpolated surfaces. While all the methods failed to reproduce the complexity of the true infiltrability distribution, conventional inverse-distance weighting produced the most accurate surfaces. There was no significant increase in accuracy for grid saturation densities in excess of 25%, nor was there any advantage to interpolating with log infiltrability instead of infiltrability.