Page Banner

United States Department of Agriculture

Agricultural Research Service

WEPP Validation Datasets
headline bar

Hillslope Validation Data

Each hillslope validation dataset contains input files for the WEPP model. To use the data download all the files in a set and unzip to any directory. Next locate a WEPP model program, in the WEPP Windows interface the WEPP model is located in the subdirectory wepp under the main installation directory. Copy the file wepp.exe to the same location where the zip files were unzipped. In each sub-directory there is batch file, runwepp.bat that will run each management scenario for the location and place the output files in the 'output' subdirectory. Double-click on the runwepp.bat file to run the simulations for the location. The main wepp output file will have an an extension of .out.

Bethany,MO - compiled according to measured USLE field -plot data collected during 1931-1940 at Bethany, MO.The plots on this site were 22.3 m by 1.8 m with an uniform slope of 7%. The soil series on the site is Shelby (sil) which has 29% clay, 27.8% sand, and 3.02% organic matter in tillage layer.

Castana, IA - compiled according to measured USLE field -plot data collected during 1960-70 at Castana, IA. The plots on this site were 22.13 m by 1.8 m with an uniform slope of 14%. The soil series on the site is Monona (sil) which has 23.5% clay, 7.1% sand, and 2% organic matter in tillage layer

Geneva, NY - compiled according to measured USLE field -plot data collected during 1937-1946 at Geneva, NY. The plots on this site were 22.3 m by 1.8 m with an uniform slope of 8%. The soil series on the site is Ontario (l) which has 14.9% clay, 44.2% sand, and 4.5% organic matter in tillage layer.

Guthrie, OK - compiled according to measured USLE field -plot data collected during 1942-1956 at Guthrie,OK. The plots on this site were 22.12 m by 1.8 m with an uniform slope of 7.7%. The soil series on the site is Stephensville (fsl) which has 7.9% clay, 73.2% sand, and 1.6% organic matter in tillage layer.

Holly Springs, MS 1 - compiled according to measured USLE field-plot data collected during 1961-68 at Holly Springs, MS. The plots on this site were 22.13 m by 4.07 m with an uniform slope of 5%. The soil series is Providence (sil) which has 19.8% clay, 2% sand, and 0.81% organic matter. This climate file is from 1961 to 1968. Therefore, to run the rotation management file which is from 1962 to 1968, the data of 1961 in this climate file should be removed, and a new climate file should be created.

Holly Springs, MS 2 - compiled according to measured USLE field-plot data collected during 1970-80 at Holly Springs, MS. The plots on this site were 22.13 m by 4.07 m with an uniform slope of 5%. The soil series is Providence (sil) which has 19.8% clay, 2% sand, and 0.81% organic matter.

Madison, SD - compiled according to measured USLE field-plot data collected during 1962-1970 at Madison, SD. The plots on this site were 22.13 m by 4.05 m with an uniform slope of 5.6%. The soil series on the site is Egan (sicl) which has 32.2% clay, 7% sand, and 3.7% organic matter in top tillage layer.

Morris, MN - compiled according to measured USLE field-plot data collected during 1962-1970 at Morris, MN. The plots on this site were 22.13 m by 4.06 m with an uniform slope of 5.9%. The soil series on the site is Barnes (loam) which has 23.2% clay, 39.4% sand, and 3.4% organic matter in top tillage layer.

Pendleton, OR - compiled according to measured USLE field-plot data collected during 1979-1989 at Pendleton, OR. The plots on this site were 33.53 m by 4.05 m with an uniform slope of 16%. The soil series on the site is Thatuna (sil) which has 23% clay, 28% sand, and 4.3% organic matter in top soil layer.

Presque Isle, ME - compiled according to measured USLE field-plot data collected during 1961-1965 at Presque Isle, ME. The plots on this site were 22.13 m by 3.7 m with an uniform slope of 8%. The soil series on the site is Caribou (Gr-l) which has 13.7% clay, 38.8% sand, and 3.8% organic matter in the tillage layer.

Tifton, GA - compiled according to measured USLE field-plot data collected during 1979-1989 at Tifton, GA. The plots on this site were 25.3 m by 8. m with an uniform slope of 3%. The soil series on the site is Tifton (sl) which has 5.7% clay, 87% sand, and .7% organic matter in top soil layer.

Watkinsville, GA - compiled according to measured USLE field-plot data collected during 1961-1967 at Watkinsville, GA. The plots on this site were 22.3 m by 6.3 m with an uniform slope of 7%. The soil series on the site is eroded Cecil (scl) which has 19.6% clay, 39.4% sand, and 0.89% organic matter in tillage layer.

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'.


Watershed Validation Data

Chickasha, OK c5 - Input files for watershed c_5, Chickasha, OK (3 hillslopes, 3 channels) 1971-1974

Coshocton, OH 109 - Input files of watershed 109, Coshocton, OH (2 hillslopes, 3 channels) 1979-1989

Coshocton, OH 191 - Input files of watershed 191, Coshocton, OH (3 hillslopes 1 channel) 1979-1989

Coshocton, OH 130 - Input files of watershed 130 Coshocton, OH (3 hillslopes 1 channel) 1987-1993

Holly Springs, MS 1 - Input files of watershed 1, Holly Springs, MS (9 hillslopes 6 channels) 1970-1977

Holly Springs, MS 2 - Input files of watershed 2, Holly Springs, MS (7 hillslopes 5 channels) 1970-1972

Holly Springs, MS 3 - Input files of watershed 3, Holly Springs, MSA (6 hillslopes 3 channels) 1970-1977

Riesel, TX w-12 - Input files of watershed w-12, Riesel, TX (1 hillslope 2 channels) 1987-1992

Riesel, TX w-13 - Input files of watershed w-13, Riesel, TX (1 hillslope 1 channel) 1987-1992

Riesel, TX sw-12 - Input files of watershed sw-12, Riesel, TX (5 hillslopes 5 channels) 1989-1992

Tifton, GA z - Input files of watershed Z, Tifton, GA (3 hillslopes 4 channels) 1968-1986

Watkinsville, GA p-1 - Input files of watershed p1, Watkinsville, GA for 1972-82
(8 hillslopes 5 channels) 1972-1982

Watkinsville, GA p-2 - Input files of watershed p2, Watkinsville, GA (6 hillslopes 4 channels) 1973-1975

Watkinsville, GA p-3 - Input files of watershed p3, Watkinsville, GA (6 hillslopes 9 channels) 1972-1982

Watkinsville, GA p-4 - Input files of watershed p4, Watkinsville, GA
(8 hillslopes 11 channels) 1973-1982

Fifteen small watersheds from 0.34 to 5.14 hectares in area from six locations in the United States were used in this study. Land use for these watersheds included crop rotations, no-till corn and meadow. To run the WEPP watershed model, information was needed on climate, soil, management, topography, channel geometry, and channel control structure. Also, each watershed had to be divided into different hillslope, channel and impoundment elements, and the overland flow routing between them had to be provided to WEPP. All of this information was compiled into six to eight input files. They are climate, soil, management, slope, channel, irrigation (if needed), impoundment (if needed) and watershed structure files.

Because of the small watershed size, we were able to use a single climate input file for each watershed. All the input files were created using WEPP version 94.7 file formats.

CLIMATE INPUT FILES

WEPP climate input files contain ten daily parameter values. The four precipitation parameters were precipitation amount, duration, ratio of time to rainfall peak / rainfall duration (TP), ratio of maximum rainfall intensity / average intensity (IP). These four parameters were calculated using breakpoint precipitation data for all locations except the p3 and p4 watersheds in Watkinsville, Georgia. Since the breakpoint data were not available for these two watersheds, and they were about 3.5 kilometers away from the p1 watershed, we used the p1 watershed's TP and IP values for the p3 and p4 watersheds. The p3 and p4 watersheds were very close, so the same climate file was used for both locations. The other six daily climate parameters (maximum temperature, minimum temperature, solar radiation, wind velocity, wind direction, and dew point temperature were generated by the WEPP weather generator, CLIGEN (Nicks et al., 1995). In addition, the rainfall data for the Z watershed in Tifton, Georgia were 5-minute punch rainfall records. The data were recorded every 5 minutes. Rainfall amounts could be 0, 0.1, 0.2, 0.3 inches, and so on for each 5 minute time period. Thus the accuracy of the total storm duration and the ratio of maximum of intensity / average intensity for each storm were poor for this location.

SLOPE INPUT FILES

According to the watershed topography and soils, each watershed was divided into several hillslopes and channel elements. The slope steepness, slope length, and element width were calculated using the topographic maps for each hillslope and channel.

MANAGEMENT INPUT FILES

Tillage and crop management information were entered into the plant/management files according to the field operation notes. These data included tillage equipment and date, planting date and what crop was planted, harvest date, residue management etc. Most of the plant specific parameters used were WEPP default values at the medium productivity level. If a plant was not available from the WEPP defaults, we used the Crop Parameter Intelligent Database System (Deer-Ascough et al., 1995) and other data to estimated the parameters.

SOIL INPUT FILES

Basic soil characteristics, including percentages of sand, clay, organic matter, rock fragments and cation exchange capacity were obtained from measured data. The three soil erodibility parameters (baseline interrill erodibility, baseline rill erodibility and baseline critical shear stress) were estimated by using the WEPP default estimations. The effective hydraulic conductivity of the surface soil was predicted using the WEPP estimation equations except for the Grenada silt loam soil in Holly Springs, Mississippi, in which we used the optimized value of 0.47 mm/hr. This optimization, which was made by Risse et al., was obtained by using the field fallow plot data (Risse et al., 1995a) from the Grenada soil.

CHANNEL INPUT FILES

Channel parameters varied from watershed to watershed and from channel to channel. The EPIC peak runoff calculation method was used. The friction slope calculation method used the friction slope equal to the channel bed slope. The channel erodibility and critical shear stress used WEPP estimated values. The bare soil and total Manning roughness coefficients used were from the CREAMS document table II - 28 ( Forst et al., 1980).

IRRIGATION INPUT FILE

Only one watershed in Tifton, Georgia was irrigated. The actual date and water amount were input in WEPP Fixed-Date Irrigation Scheduling format.

WATERSHED STRUCTURE FILES

The watershed structure files were created according to how the watersheds were divided and what the overland flow directions were. These files provide the water and sediment routing linkages for the WEPP watershed components (i.e. runoff from which element(s) flows into what other element until finally flow exits at the watershed outlet).

 


Last Modified: 10/15/2009
Footer Content Back to Top of Page