Paper No. 96139 of the Journal of the American Water Resources Association (formerly Water Resources Bulletin). Discussions are open until December 1, 1997.
NATURAL EROSION RATES AND THEIR PREDICTION IN THE IDAHO BATHOLITH1
Version of Record online: 8 JUN 2007
JAWRA Journal of the American Water Resources Association
Volume 33, Issue 3, pages 689–703, June 1997
How to Cite
Clayton, J. L. and Megahan, W. F. (1997), NATURAL EROSION RATES AND THEIR PREDICTION IN THE IDAHO BATHOLITH. JAWRA Journal of the American Water Resources Association, 33: 689–703. doi: 10.1111/j.1752-1688.1997.tb03542.x
- Issue online: 8 JUN 2007
- Version of Record online: 8 JUN 2007
- granitic soil;
- soil erodibility;
- storm erosivity;
- forest soils;
- undisturbed rates of erosion;
- watershed management
ABSTRACT: Natural rates of surface erosion on forested granitic soils in central Idaho were measured in 40 m2 bordered erosion plots over a period of four years. In addition, we measured a variety of site variables, soil properties, and summer rainstorm intensities in order to relate erosion rates to site attributes. Median winter erosion rates are approximately twice summer period rates, however mean summer rates are nearly twice winter rates because of infrequent high erosion caused by summer rainstorms. Regression equation models and regression tree models were constructed to explore relationships between erosion and factors that control erosion rates. Ground cover is the single factor that has the greatest influence on erosion rates during both summer and winter periods. Rainstorm intensity (erosivity index) strongly influences summer erosion rates, even on soils with high ground cover percentages. Few summer storms were of sufficient duration and intensity to cause rilling on the plots, and the data set was too small to elucidate differences in rill vs. interrill erosion. The regression tree models are relatively less biased than the regression equations developed, and explained 70 and 84 percent of the variability in summer and winter erosion rates, respectively.