USDA ARS National Sedimentation Laboratory

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USDA ARS National Sedimentation Laboratory

• Mathias J.M. Römkens
• USDA ARS NSL
• Oxford, MS 38655

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USDA ARS National Sedimentation Laboratory
Mission The research program at the National
Sedimentation Laboratory (NSL) emphasizes
interdisciplinary research dealing with the
processes of soil erosion transport and
deposition of sediment the impact of
agricultural practices, in-stream structures, and
bank protection on these processes movement of
chemicals and water quality issues on upland
areas and in streams related to agricultural
practices and the ecological well-being of
streams and adjacent riparian zones. The NSL has
three research units Channel and Watershed
Processes, Upland Erosion Processes, and Water
Quality and Ecological Processes.
Important Customers, Stakeholders, and
Partners Mississippi Agricultural and Forestry
Experiment Station (MAFES), Mississippi
Department of Environmental Quality (MDEQ),
Mississippi State University (MSU), Mississippi
Soil and Water Conservation Commission (MSWCC),
U.S. Army Corps of Engineers (COE), USDA-Natural
Resources Conservation Service (NRCS), U.S.
Environmental Protection Agency (USEPA), U.S.
Geological Survey (USGS), University of
Mississippi (UM)
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Historical Perspective and Accomplishments
The beginnings of the National Sedimentation
Laboratory research program was established on
September 1, 1956. Senate document 59 of the
86th Congress charged that the NSL be the
National Center for sedimentation research.
Major accomplishments include

• 1. Design, development, and testing of low drop
  grade control structures, which have widely been
  constructed in the Demonstration Erosion Control
  (DEC) watersheds.
• Development of stream bank stabilization
  techniques, such as vegetative approaches,
  riprap, bank toe protection, etc.
• Design and development of streambed corridor
  restoration techniques with ecologically sound
  engineering approaches.
• Application of bore hole method to determine the
  cohesiveness and permissible stress regime of
  bank material for channel stability algorithm
  calculations.
• Collection of large watershed databases (Pigeon
  Roost, Goodwin Creek) for bluff line watersheds.
• Contribution to fundamental knowledge in sediment
  transport of bed load and suspended load.
• Reservoir sedimentation research, which includes
  the use of radioactive isotopes from fall-out and
  more recently of acoustical techniques.
• Conservation tillage research for the
  southeastern USA at Holly Springs (MAFES).
• Major contributions from NSL scientists in the
  development of the Revised Universal Soil Loss
  Equation (RUSLE), the updated versions of
  Agricultural Non-Point (AGNPS) source pollution
  model, the Conservational Channel Evolution and
  Pollutant Transport System (CONCEPTS) and
  transfer of this technology to the NRCS.
• Measurement of insecticide wash-off from plant
  canopies.
• Research on fundamental processes and mechanics
  of upland soil erosion.
• Quantification of effects of suspended and
  deposited sediment on aquatic ecosystems.
• Sediment yields and associated pesticide movement
  on flat land areas in the Mississippi Delta.
• 14. Approaches for the development and
  evaluations of clean sediment TMDLs (Total
  Maximum Daily Load).

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Erosion Processes on Upland Areas
Soil erosion in watersheds is a complex process
involving soil detachment, sediment transport,
infiltration, overland flow modified and impacted
by soil, soil profile, and soil surface
conditions, mulch, slope length, and steepness.
The ability to identify the sources of sediment,
to understand how sediment moves, and to
accurately measure, interpret, and predict the
amount of sediment a stream or river carries is
fundamental to better watershed management.
Studies of infiltration and sediment transport
processes will improve our prediction capability
and should identify ways of developing more
effective erosion control technologies on upland
areas. Infiltration studies are designed to
improve predictions of rain infiltration and thus
runoff for (1) sealing susceptible soils and (2)
swelling/cracking soils. Sediment transport
studies focuses on the mechanism and mode of
sediment movement in shallow overland flow. Soil
erodibility studies are designed to improve soil
loss predictions for different soils, soil
conditions and erosion mechanism.
Sediment transport in shallow flow
Past soil erosion evidence
Infiltration studies into cracked soils
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Upland Field Management for Improved Erosion
Control
Achieving watershed-scale erosion control
requires an integrated approach of good land
management practices, stream protection and
stabilization measures, and measures to enhance
local terrestrial and aqua ecosystems. Cropping
and land management practices that are based on a
scientific understanding of all hydrologic,
erosion, and runoff processes involved are tested
on plot, field, and watershed scales. Erosion
control practices that have received research
emphasis in recent years include (1) no-till
farming systems that are productive and
profitable, and (2) cover crops that reduce
erosion, suppress weeds and improve soil
conditions, (3) buffer strips that filter
sediment laden overland, and (4) grassed
waterways that protects the soil from over land
flow incisions. Other areas of interest are
drainage, impoundments, residue management and
terraces.
Grass hedges (vegetative barriers) slow and
spread runoff, trap sediment, and prevent gully
formation.
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Hydraulic, Fluviogeomorphological, and Bank
Stability Research
All rivers and streams transport sediment, but
land mismanagement can cause severe changes in
hydrology and sediment load, adversely impacting
farm productivity, flood control, infrastructure,
and water quality and ecology. The ability to
identify the sources of sediment, to understand
how sediment moves, and to accurately measure,
interpret, and predict the amount of sediment a
stream or river carries is fundamental to better
watershed management. Research at the NSL
focuses on small and large scale processes of
sediment transport and river channel change.
Hydraulic flumes are used to examine the
processes of sediment entrainment and transport
typical of upland areas, agricultural fields, and
rivers. Intensive field research programs
examine the processes responsible for the
collapse of stream banks and long-term river
adjustments to land mismanagement and
channelization. These studies are used to
construct and validate watershed management tools
and technology.
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Demonstration Erosion Control(DEC) Project
High annual rainfall, steep hillsides, extremely
erosive soils, and cropping systems that afford
poor surface protection, make northwestern
Mississippi one of the most fragile landscapes in
the world. The Demonstration Erosion Control
Project (DEC) addresses problems associated with
watershed erosion, sedimentation, flooding, and
environmental degradation. Since 1984, DEC has
been a collaborative effort between the NSL, the
U.S. Army COE and the USDA-NRCS targeting 16
watersheds within the Yazoo River Basin of
northwest Mississippi. DEC activities include
planning, design, construction, monitoring and
evaluation to reduce flooding, erosion, and
sedimentation problems by applying
environmentally sound management practices.
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Conservation Effect Assessment Project (CEAP)
In the 2002 Farm Bill, the U.S. Congress mandated
that USDA-NRCS determine the effectiveness of
USDA conservation programs (e.g., EQIP, CRP, WRP,
WHIP). NRCS is partnering with ARS to assess
these programs at the watershed scale level. The
program has two major components and reporting
scales (1) The National Assessment provides
estimates of conservation benefits at the
national scale for annual reporting beginning in
2005, and (2) the watershed assessment studies
provide for more detailed assessments of all
benefits in selected watersheds and will begin
reporting in 2006. The NSL is participating in
CEAP with Mississippis NRCS staff in all
components at both scales. In the first tier of
12 watersheds selected nationwide in the CEAP
project, Mississippis Yalobusha River Basin
upstream of Grenada Lake (300 mi2), the Goodwin
Creek Experimental Watershed (8.1 mi2) near
Batesville, and the Beasley Lake (4000 ac) MSEA
watershed in Sunflower County were chosen for
participation.
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Yalobusha River-Little Topashaw Creek Project
The NSL is currently conducting a wide range of
investigations within the 842-km2 Yalobusha River
watershed in northern Mississippi that target
problems associated with gully and channel
erosion. This watershed, part of the DEC project
since 1997, experiences accelerated channel
erosion in the uplands and frequent flooding
downstream due to a plug of sediment and woody
debris that has formed in the channelized river.
Little Topashaw Creek, a rapidly eroding
tributary, was selected for a wide range of
intensive studies, including stream bank and bed
erosion processes, the use of woody debris for
low-cost channel stabilization and habitat
restoration, and the use of vegetation to control
channel and gully erosion. Across the watershed,
the NSL is monitoring channel erosion rates and
measuring the strength of bed materials to
improve understanding of processes, and to help
our partners target their channel protection work
more effectively.
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Goodwin Creek Experimental Watershed
Goodwin Creek, a 21.3 km2 , mixed land-use
watershed in north central Mississippi was
established with construction funds provided by
the COE and has been operated by the NSL. This
watershed offers a 20 year data base of
hydrologic, geomorphic, and sediment transport
measurements. This watershed has 13 gaging
stations consisting of supercritical flumes and a
hydrometerological station that is an integral
part of NOAAs national network (GEWEX SURFRAD,
SCAN). Goodwin Creek is part of the ARS
national network of fifteen instrumented
watersheds that serve as stable, high quality
research platforms for process understanding,
consistent historic databases, and magnets for
scientific collaboration. Several years of
modeling research and testing on Goodwin Creek
led to the development of the new AGNPS 2001
watershed management tool. The Goodwin data base
is extensively used by other Federal Agencies and
Universities.
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Headcut, Rill and Ephemeral Gully Erosion
Headcuts are places on fields where the most
severe form of erosion is taking place. Field
and laboratory research studies are providing a
better understanding why headcuts and rills
develop and quantify this phenomenon relative to
(1) characteristics of the overland or channel
flow regime, (2) the geo-technical and soil
mechanical or soil physical properties of the
soil material, and (3) the stratigraphy and soil
water pressures of the soil profile.
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Water Quality Research
Maintaining high quality surface water and ground
water supplies has long been recognized as a
national priority. Federal guidance and mandates
such as the 1972 Clean Water Act and the
Presidential Initiative on Water Quality provide
the authorization for research on water
quality. Surface water bodies. Water quality
data collected as a part of the Demonstration
Erosion Control (DEC) and the Management Systems
Evaluation Area (MSEA) projects indicate the
effectiveness of erosion control and Best
Management Practices (BMP) in reducing erosion
and nonpoint source pollution. Linking water
quality to downstream ecology. Scientists
ascertain biological (e.g., fish and aquatic
insects populations) response relationships to
agricultural pollutants (sediment, nutrients,
pesticides, and metals) for developing Total
Maximum Daily Loads (TMDL) and water quality
criteria for fully functional water-bodies.
Additionally, bioassays in which laboratory
organisms are exposed to water or bottom sediment
samples are used to help indicate the sites
overall water quality and ecosystem
health. Shallow groundwater. Shallow ground
water monitoring in field borders has shown that
many agrochemicals do not leave Mississippi Delta
fields, but are processed at or near the surface
and do not present a human or aquatic threat.
Pesticides were measured in only 5 of over 600
groundwater samples and median nitrate
concentrations less than one ppm, indicating
minimal risks from farming activities in the
vicinity of oxbow lake watersheds.
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TMDL andNutrient Criteria Research
Excessive erosion, transport, and deposition of
sediment and other contaminants in surface waters
are major national problems. According to the
USEPA, almost 7700 (16) of the 303(d) listed
water body impairments are caused by sediments
and/or siltation, while nearly 5500 (11) are
caused by excessive nutrients. A national
strategy is needed to develop scientifically
defensible procedures to aid in developing TMDLs
for these impairments. In cooperation with the
USEPA and MDEQ, NSL scientists are developing
improved methodologies to evaluate the likelihood
that a stream is impacted from a change in the
amount of clean sediment. Defining linkages
among channel evolution stage, frequency and
duration of sediment transport events, biological
integrity of a stream, and rectification of
streams using BMPs, is one of the main goals of
this project. NSL scientists are also studying
ways to reduce nutrient runoff, while offering
current data for development of scientifically
sound nutrient criteria for rivers, streams, and
lakes.
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Acoustic Research in Soils and Sediment
Channels Acoustic backscatter sensors are being
used to measure depth to the bed and
concentration of suspended sediment in the
flowing waterway. Multiple acoustic frequencies
are being tested to obtain particle size
information, removing the necessity for separate
particle size measurements. Soils Acoustic to
seismic coupling is being used to measure the
depth to the fragipan (a hard, water confining
layer). This technique may allow quick mappings
of the fragipan soil productivity. Passive
acoustic techniques are being used to measure the
flow of water through soil. Each time water
leaves a pore in the soil acoustic waves are
emitted and picked up with passive sensors.
These emissions can tell us how water moves
through soil at the smallest scales. Sediments
Acoustical techniques offer unrivaled
opportunities to visualize the subsurface
stratigraphy within sediment-landen reservoirs.
A complete seismic or acoustic survey of a
35-acre lake can be accomplished in as little
time as two hours. Geophysical techniques often
require prior knowledge by the user for obtaining
and post-processing the data, and sediment cores
aid in data interpretation.
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Aquatic Ecology and Habitat Restoration
NSL scientists develop methods for improving
ecosystem function within watersheds, lakes, and
streams. Enhancing habitat. Research has
demonstrated that by modifying existing erosion
control structure designs both aquatic habitat
and the life it supports may be enhanced. In
some cases, the addition of as little as 10 more
rock to existing erosion control structures
results in significant increases in biodiversity
and fish growth. Design criteria for
cost-effective measures to remedy problems and
rehabilitate damaged stream channel ecosystems
have been developed using dormant willow post.
These cost effective methods of rapidly
re-establishing riparian vegetation provide
habitat, stream bank stability and carbon for
stream dwelling organisms.
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Edge-of-Field Management
This research focuses on developing, evaluating,
and improving new technologies and best
management practices to reduce runoff of sediment
and chemicals from agricultural fields into the
stream system. These technologies
include Vegetative buffer areas. Grassed
waterways, vegetated field borders, filter
strips, stiff-grass hedges, and forested riparian
buffers. Structural improvements. Control
structures such as slotted-inlet drop pipes,
slotted board risers to prevent concentrated flow
erosion and attenuate peak runoff rates and tile
drains. Ditches to clean runoff. Vegetated
ditches surrounding agricultural fields can
capture and retain a portion of potential
agricultural contaminants and prevent them from
damaging the water quality and aquatic life in
rivers, streams, or lakes. Natural and
constructed wetlands. Determine efficacy and
impact of wetland systems in improving water
quality and ecosystem integrity.
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ModelingRUSLE, AGNPS 2001, and CONCEPT
Erosion and watershed water quality modeling
technologies developed through the research of
NSL scientists are used in soil conservation and
water quality management planning, to evaluate
sources of sediment, and the impact that control
measures have on sediment yield and TMDLs at the
watershed scale The Revised Universal Soil Loss
Equation (RUSLE) is a computer program that
estimates rates of soil erosion caused by
rainfall and associated overland flow. RUSLE is
widely used to assess the degree of rill and
interrill erosion, identify situations where
erosion is serious, and guide development of
conservation plans to control erosion. The AGNPS
2001 project is a joint NRCS and ARS system of
computer models developed to predict non-point
source pollutant loadings within agricultural
watersheds. This technology is used to evaluate
the impact of BMPs on water quality within a
watershed. The AGNPS 2001 watershed system
models the interaction of processes that are
important in assessing sources of sediment.
Loadings from the fields are simulated by
AnnAGNPS. CONCEPTS simulates the channel
evolution.
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Technology Transfer
New knowledge and technology have no impact until
end users become familiar with them. The NSL
strives to disseminate its findings through many
channelsthe scientific literature, popular press
and trade publications, oral presentations to
scientific and community groups, and one-on-one
conversations with producers, resource managers
or anyone else with an interest in soil and water
resources. Field days and site visits are
essential opportunities to interact with
stakeholders in the real-world arena. Additional
technology transfer and outreach efforts are made
through the NSLs Adopt-A-School program, where
scientists interact with local elementary and
middle school students and teachers, by bringing
their research interests directly to the
classroom. Laboratory tours are also popular
methods used to expose local students to the
NSLs agricultural and environmental research.
The NSL website provides avenues to learn more,
contact individual scientists, and download the
latest versions of NSL software.
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Permanent Scientific Staff
Martin A. Locke, RL, Soil Scientist 662-232-2908,
mlocke_at_msa-oxford.ars.usda.gov Matthew T. Moore,
Ecologist 662-232-2955, mtmoore_at_msa-oxford.ars.usd
a.gov Fred E. Rhoton, Soil Scientist 662-232-2938
, frhoton_at_msa-oxford.ars.usda.gov Mathias J.M.
Römkens, RL, LD, Ag. Engineer/Soil Scientist
662-232-2940, mromkens_at_msa-oxford.ars.usda.gov F.
Doug Shields, Research Hydraulic
Engineer 662-232-2919, dshield_at_msa-oxford.ars.usda
.gov Andrew Simon, Geologist 662-232-2918,
asimon_at_msa-oxford.ars.usda.gov Sammie Smith,
Research Chemist 662-232-2936, ssmith_at_msa-oxford.a
rs.usda.gov Glenn V. Wilson, Hydrologist 662-232-
2927, gvwilson_at_msa-oxford.ars.usda.gov Daniel
G. Wren, Civil Engineer 662-232-2926,
dwren_at_msa-oxford.ars.usda.gov
Carlos V. Alonso, RL, Hydraulic
Engineer 662-232-2969, calonso_at_msa-oxford.ars.usda
.gov Ronald L. Bingner, Agricultural
Engineer 662-232-2966, rbingner_at_msa-oxford.ars.usd
a.gov Charles M. Cooper, Ecologist 662-232-2935,
ccooper_at_msa-oxford.ars.usda.gov Robert F.
Cullum, Agricultural Engineer 662-232-2976,
bcullum_at_msa-oxford.ars.usda.gov Seth M. Dabney,
Research Agronomist 662-232-2975,
sdabney_at_msa-oxford.ars.usda.gov David DiCarlo,
Physical Scientist 662-281-5705,
ddicarlo_at_msa-oxford.ars.usda.gov Scott S.
Knight, Ecologist 662-232-2934,
sknight_at_msa-oxford.ars.usda.gov Eddy Langendoen
Hydraulic Engineer 662-232-2924
elangendoen_at_msa-oxford.ars.usda.gov Post
Doctoral Fellows Yuan Yongping, Ag. Engineer
Chris Wilson, Geomorphologist Robert Wells,
Civil Enginee