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Watershed Assessment and Modeling
Watershed assessment and modeling tries to determine what are the sources and factors that affect delivery of critical pollutants in a watershed. Geographical Information System (GIS) land use/land cover research often plays a critical role in such watershed assessment and modeling efforts. Research through NIFA and the Land Grant System explores new tools, methods, and models that can help decision makers make better watershed management decisions.
Research pertaining to "Watershed Assessment and Modeling" can
be broken into the following categories (linked further down on this page):
GIS
Land Use/Land Cover Research
New
Watershed Assessment Methods and Models
Evaluation
of Watershed Sinks
Highlighting Partner
Activities
GIS Land Use/Land Cover Research
Examining the different types of land use and land cover within a watershed
can reveal important information about potential sources of contamination
to its water bodies. GIS-based tools, being developed at Land Grant Universities
and with NIFA funding, help to determine land use composition for a given
geographical area and identify those water resources at the highest risk
from agricultural or other human activities. Other research is being
conducted to determine the impact of various types of cover on water quality.
Accomplishments:
Research has shown
the amount of impervious surface in a watershed to be a reliable indicator
of the impacts of development on water resources. The
Impervious
Surface Analysis Tool (ISAT) 
is
an ArcView extension developed through a partnership between the University
of
Connecticut (UCONN) Nonpoint
Education for Municipal Officials (NEMO) and
the National Oceanic and Atmospheric Administrations’s
Coastal Services Center (NOAA/CSC). It is used to calculate
the percentage of impervious surface
area of user-selected geographic areas (e.g., watersheds, municipalities,
subdivisions) and incorporates land cover change scenarios to
examine how these changes influence impervious surfaces. ISAT is helping communities
minimize impervious surface
as a result of land use change therefore protecting watershed health and water
quality. The UCONN Geospatial
Technology Program (GTP) developed
population density-related impervious surface coefficients in 2002, and used
them along with ISAT to generate accurate
impervious surface estimates
for 244 watersheds.
At North Carolina
State University, studies on the infiltration
rate of permeable pavements are
being conducted. The focus of these studies is to determine infiltration rates
and the amount of runoff reduction associated with permeable pavement use,
as well as the impact of permeable pavement on water quality.
New Watershed Assessment Methods and Models
Watershed assessment methods and models are continuously improving with the
help of new technology and research completed at Land Grant Universities
and with NIFA funding. These models can be incorporated into tools that
predict watershed responses to various types of land use, human impacts,
and management practices. Once developed, these new tools can often be made
accessible to their target audiences on the Internet. This provides decision
makers with a wealth of research-based information to help them manage watersheds
and improve water quality.
Evaluation of Watershed Assessment Models:
A regional effort
in the NIFA Southern Region is developing
and evaluating TMDL planning and assessment tools and processes .
The goals of the project are to: develop, improve and evaluate watershed models
and other approaches for TMDL development and implementation; assess potential
economic benefits and costs and equity issues associated with TMDL implementation
at the watershed and individual landowner scale; and assess the potential ecological
benefits and implications of TMDL implementation at the watershed level.
Evaluating Pollution Risks of Different Land Uses:
MANAGE is
a watershed assessment tool, developed by the University
of Rhode Island NEMO ,
that uses computer-generated maps to evaluate pollution
risks of land use and landscape features. MANAGE evaluates the cumulative
effects of current land use, future development and pollution management practices
on water resources.
MANAGE has been tested and successfully applied in several Rhode Island communities.
In these communities, MANAGE results have led to actions that protect local
water resources, such as strengthening groundwater protection regulations,
managing on-site wastewater systems, controlling land disturbance and expanding
public education on resource protection.
University of Arkansas
researchers are developing models that predict
the vulnerability of ground water to nitrate and pesticides 
from
agricultural
runoff in the Mississippi Delta region. The models are based on Neural Networks,
Fuzzy Logic, Neuro-fuzzy and Geostatistics, and GIS will be used to generate
vulnerability maps from the models. The results of the research will be shared
via the Internet with various stakeholders including policy makers and partners
at local, state and federal agencies.
A watershed-scale
model for
the entire Connecticut River is being developed at the University of Massachusetts
using GIS analysis and
the
Soil and Water Assessment Tool (SWAT). The objective of the model is to evaluate
the effects of land use and development practices and policies on water quality
and ecological integrity. Model development is still in progress, though
preliminary results of the analysis can be used to identify sensitive areas
of the Connecticut
River Watershed that impact water quality, helping to identify vulnerable areas
in need of protection.
Researchers at the
University of Puerto Rico are compiling a database
to predict soil erosion in
the Rio Grand de Arecibo Watershed. Data will be gathered using the Revised
Universal Soil Loss Equation
(RUSLE), and a management plan will be developed to minimize soil loss and
subsequent siltation of the Dos Bocas reservoir. Through better-informed watershed
management decisions, the project is expected to improve water quality in this
reservoir, which provides drinking water to over 1.5 million people.
Researchers at the
University of Arkansas are developing a decision support system that will link
seasonal algal growth thresholds with land use practices in
the watersheds of the Eucha Basin. The system integrates environmental and
resource management elements to develop
a risk-based strategy for water quality management in the Eucha Basin in Oklahoma
and Arkansas.
Estimating Watershed Pollutant Loads:
A project at the
University of Florida aims to estimate
nitrogen distribution in
the Santa Fe River Watershed, using a GIS-based geo-modeling approach. Site-specific
measurements of nitrate will be upscaled to the entire Santa Fe River Watershed.
A long-term goal of the project is to develop recommendations
for potential BMP implementation in the Santa Fe Watershed to reduce
nitrogen loads leaving the drainage basin.
Researchers at the
University of Vermont are developing a watershed
phosphorus model .
The project combines Water Ecosystem
Nutrient Dynamics (WEND) modeling with GIS knowledge to create a framework
for estimating phosphorus losses in a watershed that can help regional planning
and watershed management. The long-term goal of the project is to reduce phosphorus
deposits in Lake Champlain.
Kansas State University
has cooperated with the Cheney Lake Watershed organization to develop an Annualized
Agricultural Non-Point Source (AnnANGPS)
model
to estimate expected soil
and nutrient losses from an actual rainstorm as well
as predict losses for the coming year in specific parts of the watershed. The
model is intended to help the Watershed board direct their efforts and funding
to the most vulnerable parts of the watershed.
A decision support
tool, developed at Tufts University, addresses the issue
of nutrient management in watersheds .
The model integrates models of watershed nutrient loads and receiving water
quality into a decision-oriented optimization framework. This will allow stakeholders
to define and prioritize nutrient management objectives.
Evaluating Watershed Sinks
Riparian zones, transition zones between uplands and surface water, are important
locations for groundwater nitrate removal, as well as the removal of other
pollutants and sediments. Research at the Land Grant Universities and with
NIFA funding is examining the roles these riparian zones and artificial or
constructed wetlands on water quality functions at the watershed level.
Accomplishments and Examples:
Researchers at the
University of Rhode Island (URI) Watershed
Hydrology Laboratory determined
landscape controls of
riparian
zone groundwater nitrate removal .
These insights were translated into methods that can be adapted to available
spatial databases and enhance our ability
to target high value riparian zones for protection and restoration to improve
or maintain water quality. The URI
NEMO Program
has incorporated these results into their programming with municipal officials
and modeling efforts. Additional research at the Watershed Hydrology Laboratory
is examining the effect
watershed land use practices on the hydrology, soils, and groundwater
nitrate removal function of
riparian zones.
Iowa State University
researchers have demonstrated that riparian buffers
re-established
on previously
cropped or pastured land have tremendous potential to remediate
nonpoint source pollution in agricultural watersheds .
Insights from this study are being used to improve buffer performance and placement
within watersheds.
Highlighting Partner Activities
Partners of NIFA have been instrumental in watershed assessment and modeling
research. These models have been widely used in watershed management and have
been incorporated into many different decision support systems and management
tools.
Accomplishments and Examples:
Developed by the
U.S. Geological Survey, SPARROW 
is
a method for regional
interpretation of water-quality monitoring data. It
relates in-stream water quality measurements to spatially referenced characteristics
of watersheds, including contaminant sources and factors influencing terrestrial
and stream support. The model estimates the origin and fate of pollutants in
streams and quantifies the uncertainty related to these estimates.
Agricultural
Non-Point Source (AGNPS) is
a distributed parameter model developed by USDA Agricultural Research Service
scientists and engineers. It predicts soil erosion and
nutrient transport and loadings from agricultural watersheds for real
or hypothetical storm events.
The TMDL
Assessment Report issued
by the National Research Council (NRC) assesses the
scientific basis of
the
TMDL program. The report was requested by Congress following the issuance
of updated TMDL regulations by the EPA in 2000. It represents the consensus
opinion
of the eight-member NRC committee involved in the TMDL assessment and supports
a return to ambient-based water quality management while focusing on TMDL program
goals.
Indicates
work supported by the USDA-NIFA National
Research Initiative Competitive Grants Program .
The intent of this page is not to catalogue all activities but rather to indicate the types of research in the NIFA Watershed Management theme across the U.S.
