Estimating Soil Loss From Medium-Size Drainage Basins

Abstract

No perfect method exists for estimating historical soil loss from mediumsize watersheds. One approach to maximizing the accuracy for soil-loss estimates is to use a variety of different methods and compare their results for convergence. This paper compares four different methods to estimate soil loss from two medium-sized, fifthorder watersheds in southeastern Minnesota. The four comparative methods are the soil-survey and soil-truncation method (including a reevaluation of a Soil Conservation Service (SCS) study), gully-erosion estimates, reservoir-sedimentation measurements combined with estimated sediment-delivery ratios, and estimates derived from the Universal Soil Loss Equation (USLE). Although each method uses different data and procedures, their estimates of historical soil loss are comparable, excepting those for gully erosion. The estimates converged around the USLE estimate, ranging from 44 to 128% of the USLE. The soil survey and soil truncation method produced the lowest estimates, ranging from 44 to 79% of the USLE. The USLE estimate for one watershed fell in the middle of a range derived from the SCS study. The USLE computations for both watersheds ranged from 85 to 118% of the reservoir sedimentation estimate. Historical gully erosion ranged from only 3 to 15% of the different estimates of total soil loss, indicating that estimates of gully erosion alone are not good surrogates for total soil erosion. The convergence between the other watershed soil-loss methods lends a measure of credibility to the broad accuracy of the estimates.

Budgets of soil erosion and deposition for sediments and sedimentary organic carbon across the conterminous United States

“…One major source of error is not well addressed by this budget, decreasing erosion rates over time. This decrease is documented both in some individual sites [e.g., Beach, 1992;Trimble and Lund, 1982] and in the NRI database (see, for example the recently released summary of 1997 data [Natural Resources Conservation Service, 1999]. We can at least qualitatively address the effect of such an erosion decrease on the budget.…”

Quantifying prehistoric soil erosion—A review of soil loss methods and their application to a Celtic square enclosure (Viereckschanze) in Southern Germany

“…For decades, modern soil erosion has been recognized as a serious environmental problem. As a consequence a variety of methods have been developed to measure soil loss (e.g., Lewis & Lapele, 1982;Loughran, 1989;Beach, 1992). These methods vary from direct thickness measurements of erosion using tracers such as 137 Cesium in redeposited sediments (Queralt, Zapata, & Garcia-Agudo, 2000) to the application of different soil loss models for assessing rates of erosion (Hadley & Walling, 1984;Renard et al, 1991).…”

Validation of official erosion modelling based on high‐resolution radar rain data by aerial photo erosion classification

“…Tracer studies usually yield rather sparse point data from which a spatial representation has to be interpolated; they do not differentiate regarding the processes leading to a tracer loss, namely tillage and water erosion, which then has to be modelled, and they usually only have weak information about land use since the release of the tracers by nuclear bombs in the 1950s and 1960s. Mapping studies (Morgan et al ., ; Beach, ; Pradhan et al ., ) usually deliver qualitative or semi‐quantitative data only and they are normally carried out post hoc based on prominent erosion features observable after very large erosion events. Thus they do not include small events or cases where large losses would have been predicted but did not occur in reality.…”