REPORT: Performance Testing of Traditional Slope Erosion Controls

Large-scale tests have been used extensively in recent years to evaluate the performance of manufactured erosion control products on slopes. When evaluating slope erosion, a full-scale slope is generally exposed to rainfall impact and associated seepage and sheet runoff forces resulting from a simulated rainfall event. Commonly, the testing includes both slopes covered by the candidate erosion control product and slopes without any protection, or control slopes. The amount of soil loss from the protected condition is compared to that of the unprotected, or control condition, in order to establish product performance. This ratio of protected to unprotected soil losses is referred to as the Cover Factor, or simply C-Factor, and is a variable in the Revised Universal Soil Loss Equation (RUSLE) contained in the USDA-ARS Agricultural handbook 703.

While this full-scale testing is useful in establishing the maximum benefit of a candidate erosion control product, such as a rolled erosion control product (RECP) or hydraulically-applied erosion control product (HECP), it can also be used to consider if sufficient protection is afforded by more traditional erosion control alternatives. Comparing RECP or HECP performance to that of traditional alternatives may be more meaningful than simply comparing to a control, or no protection, condition, especially when performing cost-benefit analyses.

This paper will present the results of large-scale standardized performance tests on the traditional erosion control systems of blown and tacked straw and crimped straw, as well as a summary of product test results using the same large-scale testing procedure, ASTM D 6459.

Keywords: RECPs, HECPs, erosion control, NTPEP, slope erosion testing, ASTM D 6459