Hillslope Validation Data

Bethany, MO
Castana, IA
Geneva, NY
Guthrie, OK
Holly Springs, MS 1
Holly Springs, MS 2
Madison, SD
Morris, MN
Pendleton, OR
Presque Isle, ME
Tifton, GA
Watkinsville, GA

The WEPP input files including slope, soil, climate, and management files were compiled according to measured USLE field-plot data collected on each location. These files are included separately in 12 file-folders named after their locations. Raw data from these sites are stored in the erosion data repository at the USDA National Soil Erosion Research Laboratory in West Lafayette.

Conditions were uniform on each plot/treatment, thus one OFE (overland flow element) was used to construct all input files. All these input files are in the correct formats for running the WEPP version of 94.7 or greater. The following is a brief summary on how to build these files:

SLOPE INPUT FILE:
Since the topography of each plot is about the same and plot slope is nearing uniform, an identical slope input file was used for all treatments on each site. All the slope input files are in *.slp.

SOIL INPUT FILE:
Soil properties from all the plots on each site are about the same, thus only one soil input file was constructed and used for all the treatments. Baseline saturated hydraulic conductivity was estimated by parameter optimization, and baseline erodibilities were calculated using WEPP estimation equations. The rest parameters were estimated by averaging all of information obtained for the site. All the soil input files are in *.sol.

CLIMATE INPUT FILE:
CLIGEN (Climate Generator) was used to generate a continuous climate file using the measured daily temperatures and rainfall amounts. Then, measured rainfall parameters such as duration, time to peak, and peak intensity, calculated from breakpoint data, were used to substitute for the generated values . All the climate files are in the files with the extension of '.cli'.

MANAGEMENT FILES:
Since residue mass rather than crop yield directly affects hydrology and erosion, plant growth parameters were adjusted to obtain a desired above- ground biomass at harvest, based on measured data or best guess for the location. None of the selected plots on each site was cultivated in contour, so up and down tillage was assumed for all cases. All the management files have an extension of '.man'. ( If you are using a browser other than WinMosaic these files may not appear on your screen. Check the \WEPPTUT\VIEWERS\README.TXT file for more information )

EVENTS FILES:
Rainfall/runoff events were selected for each management system based on data quality. The events with no breakpoint rainfall data and mean temperatures being below zero were not selected. The events with a single storm over multiple days or many storms contributed to a single measurement of runoff and soil loss were also excluded. To prevent any bias in data set, five to fifteen events with zero measured runoff were included. The selected rainfall events along with measured runoff and soil loss were presented in the files with the extension of '.eve'.

If any clarification needed, please send Email to: wepp@ecn. purdue.edu

Any Comments Would Be Appreciated
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