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ARS Home » Midwest Area » West Lafayette, Indiana » National Soil Erosion Research » Research » Publications at this Location » Publication #337620

Research Project: Assessing Conservation Effects on Water Quantity and Quality at Field and Watershed Scales

Location: National Soil Erosion Research

Title: Impacts on predicted WEPP runoff and soil loss from use of the updated 2015 CLIGEN database compared to the existing 1995 database

item SRIVASTAVA, ANURAG - Purdue University
item Flanagan, Dennis
item ENGEL, BERNARD - Purdue University
item Frankenberger, James - Jim

Submitted to: Soil and Water Conservation Society
Publication Type: Abstract Only
Publication Acceptance Date: 3/1/2017
Publication Date: 7/30/2017
Citation: Srivastava, A., Flanagan, D.C., Engel, B.A., Frankenberger, J.R. 2017. Impacts on predicted WEPP runoff and soil loss from use of the updated 2015 CLIGEN database compared to the existing 1995 database. Soil and Water Conservation Society. p. 208.

Interpretive Summary:

Technical Abstract: CLIGEN, a stochastic weather generator, is used in the Water Erosion Prediction Project (WEPP) model for runoff and soil loss predictions. CLIGEN generates daily estimates of precipitation depth and its characteristics (time to peak, peak intensity, and storm duration), maximum and minimum temperatures, solar radiation, dew point temperature, and wind speed and direction for a single location based on long-term observed weather data. The existing database (1995 release) was derived from weather records through 1992. To evaluate the impact of more recent weather, we updated the CLIGEN database (2015 version), using a consistent 40 years of NCDC climate records (1974–2013) as opposed to inconsistent years of record in the 1995 database. Continuous (100-yr) WEPP (v2012.8) simulations were conducted for 1600 locations across the US using the stochastically generated climate for a fallow-tilled management, Miami silt loam soil, and a 22.1 m long – uniform 9% hillslope profile. Changes in average annual precipitation, maximum and minimum temperatures, and WEPP-predicted runoff and soil loss with both databases were evaluated. Comparison of average annual precipitation between the 2015 and 1995 databases showed increasing precipitation trends across most of the US, except in the northwest and southeast, where there were decreases. The range of changes in maximum average annual temperatures were quite low (-0.6 to +0.6 degC), compared to changes in minimum temperatures ranging from -0.5 to +1.5 degC. WEPP-predicted average annual runoff values were generally greater from the 2015 database at most locations in the US because of higher predicted precipitation. Changes in WEPP-predicted average annual soil loss generally followed the predicted changes in average annual runoff. Understanding the impact of updated CLIGEN climate on runoff and soil loss from this study will help stakeholders and policymakers make informed decisions for conservation planning and managements.