Geology Reference
In-Depth Information
Internet-based hillslope erosion and sediment
yield model (HEM: http://eisnr.tucson.ars.ag.gov/
hillslopeerosionmodel). The model predicts run-
off volume, sediment yield, inter-rill and rill
detachment, rill deposition, and mean concentra-
tion of sediment for each hillslope segment, pro-
vided that the lengths, slopes, percentage canopy
and surface ground cover for each hillslope seg-
ment, along with runoff volume and a soil erodi-
bility value for the entire hillslope, are known.
The HEM model produces graphs depicting the
input hillslope profile and distribution of cover
on the hillslope, and output for sediment dis-
charge, detachment and deposition, and mean
sediment concentration along the hillslope pro-
file (Lane
et al
., 1995).
The Rocky Mountain Research Station devel-
oped the Forest Service Water Erosion Prediction
Project (FSWEPP: http://forest.moscowfsl.wsu.
edu/fswepp/) interfaces (Elliot & Hall, 1997;
Elliott, 2004), which provide the capability to
evaluate erosion and sediment delivery from dis-
turbed forest and rangelands. The application
uses the Water Erosion Prediction Project (WEPP)
model (Flanagan & Livingston, 1995) to estimate
erosion rates and sediment delivered using input
values developed at the Rocky Mountain Research
Station (Elliot & Hall, 1997). The interface pro-
vides links to different applications capable of
simulating sediment yield from burned areas, a
road segment across a buffer, erosion from forest
roads, erosion from rangeland, forestland, and for-
est skid trails. The applications are linked to the
Rock:Clime climate generator with a database
from more than 2600 weather stations. The dif-
ferent applications found on the US Forest Service
WEPP Interfaces website are:
●
Cross Drain
- interface to the Water Erosion
Prediction Project soil erosion model (WEPP) to
determine optimum cross-drain spacing for exist-
ing or planned roads, and for developing and sup-
porting recommendations concerning road
construction, reconstruction, realignment, clo-
sure, obliteration, or mitigation efforts based on
sediment yield.
●
WEPP: Road
- interface to the WEPP model
that allows users easily to describe numerous
road erosion conditions. The interface presents
the results as a summary and extended WEPP
output, and has an optional log to store the results
from a series of runs.
●
Disturbed WEPP
- interface to the WEPP model
to allow users easily to describe numerous dis-
turbed forest and rangeland erosion conditions.
The interface presents the results as a summary
and extended WEPP outputs, and also presents
the probability of a given level of erosion occur-
ring the year following a disturbance.
●
WEPP FuME
- interface to the WEPP model
(WEPP) to analyse soil erosion rates associated
with fuel management activities. This interface
estimates background erosion rates, and predicts
erosion associated with mechanical thinning,
prescribed fire, and the road network.
●
ERMiT
- the Erosion Risk Management Tool
(ERMit) is a web-based application that uses the
WEPP model to estimate erosion, in probabilistic
terms, on burned and recovering forest, range and
chaparral lands, with and without the application
of erosion mitigation treatments (Robichaud
et al
., 2007). User inputs are processed by ERMiT
to combine rain event variability with spatial and
temporal variabilities of soil burn severity and
soil properties, which are then used as WEPP
input parameters. Based on 20 to 40 individual
WEPP runs, ERMiT produces a distribution of
rain event sediment delivery rates with a proba-
bility of occurrence for each of five post-fire
years.
Examples of three of these applications are
described in Chapter 16.
The WEPP (Water Erosion Prediction Project)
web interface can be found at http://milford.nserl.
purdue.edu/wepp/weppV1.html (Flanagan
et al
.,
2001, 2004). As noted in earlier chapters, the
WEPP model is significantly more complex than
the RUSLE model. Consequently, more extensive
databases must be bundled with the model in
the web interface to enable ready execution via
the Internet. In this case, over 20,000 soil data-
base records, climate described at over 2600 loca-
tions within the US, and an extensive set of land
management examples comprising operation
types and dates for cropland and rangeland, are
