Geology Reference
In-Depth Information
9
Application of WEPP to
Sustainable Management of a Small
Catchment in Southwest Missouri, US,
Under Present Land Use and with
Climatic Change
J.M. LAFLEN
USDA-ARS (retired), Buffalo Center, IA, USA
The WEPP (Water Erosion Prediction Project) is a
daily simulation model developed to predict soil
erosion on all lands. It is based on hydrology and
erosion processes - detachment of soil by raindrops
and flowing water, sediment transport by flowing
water, and sediment deposition in flowing water
and impoundments. It maintains a daily accounting
of the condition of the soil and above- and below-
ground biomass. It computes an estimate of the dis-
position of all water that falls on the land surface,
whether from rain, snow or irrigation. It computes
rates and volumes of runoff and estimates hydraulic
shear, the detaching force occurring in rills and
channels. It also computes the size distribution of
detached sediment and the size distribution of
sediment discharged from the area of interest.
It can be used on individual hillslopes (Hillslope
version), and on small watersheds (Watershed
version) as shown in Fig. 9.1. It includes soil,
climate and management databases for the United
States. It is widely used on public lands in the
US by the US Forest Service and Bureau of
Land Management. It is available on a Forest
Service website (http://forest.moscowfsl.wsu.edu/
fswepp/), on a US Department of Agriculture
website (http://milford.nserl.purdue.edu/), and it
is available for download at http://www.ars.usda.
gov/Research/docs.htm?docid
10621. The WEPP
watershed version can also be used in a GIS envi-
ronment (http://www.geog.buffalo.edu/
=
rensch/
geowepp/). Technical documentation, tutorials,
databases, and other WEPP information are also
available at http://www.ars.usda.gov/Research/
docs.htm?docid
∼
10621. It has been extensively
evaluated for a very broad range of conditions
(Laflen
et al
., 2004).
WEPP can be applied in other countries. The
biggest obstacle is developing a suitable climate
file. Methods have been prepared for developing
the climate files using existing climate records
(http://www.ars.usda.gov/Research/docs.htm?
docid
=
10621). Plant parameters will probably need
adjustment, some farm operations may need
parameter adjustment, and soil files will need to
be developed. Most information needed to develop
such parameters and files is contained in the WEPP
Help (part of the WEPP program), or in the techni-
cal documentation. WEPP contains a graphing
capability that is very helpful for evaluating plant
parameters, managements, and operations.
WEPP has been applied to various problems in
the US, the most significant being its application to
clean-up of the Rocky Flats nuclear weapons pro-
duction plant near Denver, CO. The plant made
=
