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Forest Service Engineering research to develop a model of onsite sediment production from forest roads and timber harvest areas
Burroughs, E.R., Jr. 1991.
Forest Service Engineering research to develop a model of onsite sediment production from
forest roads and timber harvest areas.
In: Proc. Forestry and Environment - Engineering Solutions,
Am. Soc. Agric. Eng., 1991, New Orleans, LA. 151-160.
Links:
Abstract:
Forest land management activities in the United States have extended and accelerated in the past
four decades into steep, mountainous lands, and into more economically and environmentally
marginal operating situations.
Also, increasing environmental awareness over the last 25 years
has focused considerable attention on the potential impacts of any forest-based activity upon the
environment. Of particular concern is soil loss leading to reduction of future forest productive
capacity, water quality degradation, damage to aquatic ecosystems, and visual degradation.
In many parts of the nation, particularly the Pacific Northwest, forest land managers have found that
their management alternatives are constrained by limits on turbidity and sediment concentration
allowed in receiving streams.
It is essential that managers have the means to predict, with
acceptable accuracy, sediment production from alternative road construction and maintenance
plans and alternative harvest area treatment practices.
In 1986, the U.S. Department of Agriculture, Agricultural Research Service, initiated the Water
Erosion Prediction Project (WEPP) for use on croplands and rangelands to replace the Universal
Soil Loss Equation.
The Forest Service joined the WEPP effort because of our interest in estimating sediment production from disturbed forest lands.
The WEPP model cannot be used in its present form on forest sites because of the many hydrologic and erosion conditions
that are not considered in the cropland WEPP model.
The goal of our work is to develop physical process
models of onsite runoff and sediment production for use on forest roads and timber harvest areas
nationwide. To do this, we must develop algorithms to estimate model parameters using easily
measured site characteristics from field sites across the nation. This "forest model" will become
an integral part of the general WEPP model.
Observations and experience by forest land managers and technical specialists nationwide indicate
that forest roads are the greatest single source of sediment delivered to receiving streams.
Probably the greatest volume of sediment produced from Alaska to California and the northern
and central Rocky Mountains comes from mass erosion associated with forest road construction
and maintenance.
A lesser volume comes from surface erosion on the forest road prism, and a
much smaller volume from landslides and surface erosion on timber harvest areas. Fall and winter
rains, and spring snowmelt runoff in the west, provide ample energy for surface erosion.
Moscow FSL publication no. 1991f
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