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United States Department of Agriculture

Agricultural Research Service

Research Project: DEVELOPMENT OF ALTERNATIVE PRACTICES FOR IMPROVED WATERSHED MANAGEMENT

Location: Cropping Systems and Water Quality Research

Title: A process based method for evaluating terrace runoff and sediment yield

Authors
item Shao, Hui -
item Baffaut, Claire
item Gao, Jian'en -

Submitted to: ASABE Annual International Meeting
Publication Type: Proceedings
Publication Acceptance Date: December 2, 2011
Publication Date: July 29, 2012
Citation: Shao, H., Baffaut, C., Gao, J. 2012. A process based method for evaluating terrace runoff and sediment yield. ASABE Annual International Meeting. 121341006.

Technical Abstract: Terraces have been proven to be an effective conservation practice for controlling high soil loss. In large hydrological programs such as SWAT, terrace effects are simulated by adjusting the slope length and the USLE P-factor. In this study, a computer program based on the SCS curve number method, MUSLE and the Kodatie model, was developed to simulate each segment of the terraced slope and estimate water storage and sediment deposition on the terrace. A previously published 4-month long dataset with 10 runoff events collected on a natural rainfall runoff plot in southwest China in 2008 was used for verification. Preliminary results showed that the program simulated terrace effects with average errors ranging from 3 to 25 percent for original and terraced slope runoff and sediment simulation. The average errors in terrace runoff and sediment reduction effects were less than 10 percent. Based on the simulation outcome of this program, the runoff and sediment yield were reduced by 88.00 percent and 97.55 percent if the entire slope was terraced in the dataset period. This program could be incorporated into hydrological models such as the SWAT model for process-based evaluation of terrace effects at field and watershed scales. Its physical basis provides a useful alternative to the use of the P-factor to characterize the effectiveness of terraces.

Last Modified: 4/17/2014
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