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United States Department of Agriculture

Agricultural Research Service

Research Project: DEVELOPMENT OF MODELS AND CONSERVATION PRACTICES FOR WATER QUALITY MANAGEMENT AND RESOURCE ASSESSMENTS

Location: Grassland, Soil and Water Research Laboratory

Title: Evaluation of WEPP for runoff and sediment yield prediction on natural gas well sites

Authors
item Wachal, David - STUDENT-UNIV OF N TEXAS
item Harmel, Daren
item Banks, Kenny - CITY OF DENTON
item Hudak, Paul - UNIV OF NORTH TEXAS

Submitted to: Transactions of the ASABE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 15, 2008
Publication Date: October 15, 2008
Citation: Wachal, D.J., Harmel, R.D., Banks, K.E., Hudak, P.F. 2008. Evaluation of WEPP for runoff and sediment yield prediction on natural gas well sites. Transactions of the ASABE. 51(6):1977-1986.

Interpretive Summary: Natural gas exploration and production, with nearly 30,000 new wells drilled each year in the US, requires land disturbing activities that can accelerate soil loss. Erosion modeling has been successfully used for decades to predict soil loss and conservation effects on agricultural fields, rangeland, and forests, but little research has been conducted on applying erosion models to construction sites. The objective of this research was to evaluate Water Erosion Prediction Project (WEPP) runoff and sediment yield predictions relative to measured data. Model parameters were adjusted from WEPP defaults based on available literature and model observations. A low effective hydraulic conductivity value resulted in successful runoff predictions. Similarly, increasing default rill and interrill erodibility and decreasing critical shear stress resulted in successful sediment yield prediction. WEPP performance was evaluated with several “goodness-of-fit” indicators. For one site, these values indicated “good” performance for runoff and “satisfactory” performance for sediment yield. For the second site, these values were “very good” for runoff but “unsatisfactory” for sediment yield. When measurement uncertainty was considered, model performance was “very good” for all instances. Overall, these results indicate that WEPP can effectively model runoff and sediment yields from natural gas well sites, which makes it useful for evaluating management alternatives to minimize sediment loss from such sites.

Technical Abstract: Natural gas exploration and production, with nearly 30,000 new wells drilled each year in the US, requires land disturbing activities that can accelerate soil loss. Erosion modeling has been successfully used for decades to predict soil loss and conservation effects on agricultural fields, rangeland, and forests, but little research has been conducted on applying erosion models to construction sites. The objective of this research was to evaluate Water Erosion Prediction Project (WEPP) runoff and sediment yield predictions relative to measured data. Model parameters were adjusted from WEPP defaults based on available literature and model observations. A low effective hydraulic conductivity value resulted in successful runoff predictions. Similarly, increasing default rill and interrill erodibility and decreasing critical shear stress resulted in successful sediment yield prediction. WEPP performance was evaluated with the Nash-Sutcliffe efficiency (NSE), root mean square error (RMSE)-observation standard deviation ratio (RSR), and percent bias (PBIAS). For one site, NSE and RSR indicated “good” performance for runoff and “satisfactory” performance for sediment yield. For the second site, NSE and RSE values were “very good” for runoff but “unsatisfactory” for sediment yield. Use of modified NSE and RSR to consider measurement uncertainty improved model performance to “very good” for all instances. PBIAS values indicated “very good” prediction of runoff and sediment yield from both sites. Overall, these results indicate that WEPP can effectively model runoff and sediment yields from natural gas well sites, which makes it useful for evaluating management alternatives to minimize sediment loss from such sites.

Last Modified: 9/23/2014
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