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Proceedings of the U.S. Geological Survey (USGS) Sediment Workshop,
February 4-7, 1997
SEDIMENT RESEARCH NEEDS AND RELATED SUPPORT FOR PROGRAMS OF THE
USDA--NATURAL RESOURCES CONSERVATION SERVICE
Bernard, Jerry M., USDA--Natural Resources Conservation Service, P.O. Box
2890, 12th and Independence Ave., Rm 6132, Washington, DC
(202) 720-5356, fax (202) 720-0428, email
The NRCS was formerly known as the Soil Conservation Service until
The agency's concern with sediment began with soil erosion reduction as a
primary focus in the 1930's. Over the years, the agency has collaborated
with the USDA--Agricultural Research Service to develop reliable predictive
equations for field use to determine the effectiveness of soil erosion
control practices and programs (tons of soil saved). Examples range from
the lumped parameter Universal Soil Loss Equation (USLE), Wind Erosion
Equation (WEQ), the Revised USLE (RUSLE), and the Revised Wind Erosion
Equation (RWEQ) to the process simulation model, the Water Erosion
Prediction Project (WEPP), and the Wind Erosion Prediction System (WEPS).
WEPP simulates sheet and rill erosion, concentrated flow erosion, and
sediment transport and deposition along a measured field slope, including
the sediment size distribution, which is important to water quality
impacts. Depending on the land use, WEPP can also make these estimates for
watersheds less than 2,000 acres in drainage
area. Dave Schertz, National
Agronomist, is the NRCS leader for these models. WEPP and WEPS should be
fully operational around 2000.
NRCS currently works with private landowners to protect natural resources.
This mission gives equal weight to the reduction of soil erosion rates, as
well as reducing the amount and impact of sediment on natural resources.
The NRCS relies heavily on USGS for the water and sediment data that they
collect at stream gages.
NRCS is partnering with the ARS in identifying and prioritizing research in
many subject matter areas related to the protection of natural resources,
including the prediction and control of erosion, stream restoration, and
the modeling of the effects of watershed protection actions on water
quality and other natural resources. Examples are a variety of field and
watershed scale models, including EPIC, SWRRBWQ, ANNAGNPS, MUSLE, HUSLE,
HUMUS. Key contacts in this partnering
are Lee Herndon,
Amerman, ARS, and Wil
The modeling of water quality effects of resource protection programs,
including sediment yield rates, remains high on the list of needs in the
agency. Models that are simple, reliable, and do not require users to
key-in lavish amounts of data are especially needed. The fact is that
models are the only means to route water and sediment and other pollutants
on a watershed basis and in a manner which allows planners to determine not
only the effects of treatments on dispersed areas over long time periods,
but also the treatments needed based on landscape and watershed location
and in identifying high priority treatment areas.
(in priority order)
Item #1) Sediment transport component of the Hydrologic Unit Model for the
United States (HUMUS) needs to be validated.
Model results need to be compared with USGS stream gage data and
reservoir sedimentation surveys, and the model's sediment transport
component revised and improved accordingly.
Item #2) NRCS and other state and federal agencies
involved with watershed resource protection need more reservoir
Survey activity has dropped off severely since the mid-1980's due to
perceptions that water and sediment surveys are too costly, take too much
time, cannot be repeated easily, are not accurate, and may not be needed.
Recent advances in remote sensing technology and GPS provide the ability
to perform surveys rapidly, more accurately, with less intrusion, and at
much reduced costs.
Watershed land use information is needed as support data for each survey
time period, in order to determine the conditions that produced the amount
of sediment measured. Such data also translate to effectiveness of
watershed protection programs.
More frequent surveys on a greater number of reservoirs with small
drainage areas is needed to determine changes in sediment yields effected
by various farm programs administered at the state and federal level.
Item #3) NRCS needs to transfer the operation and
maintenance of the Reservoir Sedimentation Information System (RESIS) and
make it nationally
RESIS was developed by ARS and NRCS in support of the Third Resource
Conservation Act, for a report to Congress. Reservoir survey data that was
in digital format from earlier attempts to create such a data base were put
into an INFORMIX relational data base.
RESIS is currently only accessible on three stand-alone PC's: one at the
ARS Blacklands Prairie Research Laboratory in Temple, TX (Dr. Jay Atwood);
one at the NRCS National Soil Survey Center, Lincoln, NE (Lyle Steffen);
and one at the USGS (with EROS, working on carbon sequestration study).
The data base can be queried through SQL on an ad hoc basis. It is not
networked, nor accessible to the public.
RESIS data base lacks current reservoir sedimentation survey data, as
noted above. Data base currently includes 6000+ records, with few surveys
since about 1985.
Item #4) Information about sediment toxicity and sediment
quality are needed.
Issues about water resources structure rehabilitation, decommissioning,
and changed functions will include environmental consequences of reservoir
sediment deposits exposed, eroded, excavated, etc., as a result of
Sediment toxicity maps or data base are needed to the extent that they
can be developed. The EPA started this process on coastal and harbor
areas, but needs to be extended inland.
Standards for the accurate and scientific characterization of sediment
quality or toxicity need to be developed.
Item #5) More suspended sediment and bedload sediment data
are needed on streams draining small watersheds (< 100 mi2).
Sediment yields appear to remain high in the upper Mississippi River
Basin, although farm programs have emphasized erosion controls there over
the 11 years between gage analyses done by the USGS and reported in its
National Water Report of 1995.
Some studies on small agricultural watersheds, some with drainage systems
installed and some without artificial drainage systems added, would help
clarify the conditions that are producing the sediment. What is the
contribution of off-the-farm erosion processes such as stream bank erosion
to the total yields?
Item #6) Ephemeral gully erosion predictive techniques
need to be refined.
Ephemeral gully erosion is a significant sources of sediment where this
type of erosion occurs and affects the processes of sediment transport off
Procedure is needed to identify the extent and/or location of ephemeral
gullies (recurring concentrated flow erosion in swales or at base of
opposing slopes). Present model, EGEM, requires the user to enter the
gully length as input.
Mechanics of ephemeral gully erosion need to be refined.
Jerry M. Bernard, USDA--Natural Resources Conservation Service, Washington,
DC: Currently serves as National Geologist on the Conservation Engineering
Division Staff for the National Headquarters. Experience includes emphasis
on erosion and sedimentation processes, predictions and estimates for
project areas, water quality impacts due to sediment, and the erosion and
sediment transport components of field and watershed scale water quality
models. Is the national discipline expert for geology matters in the