Water Resource Management Support
Watershed Screening Models for Water Quality Assessment
Using several different approaches to evaluating phosphorous loading including Export
Coefficient Modeling (ECM), Variable Source Area Hydrology (VSA), and calculating
variable width Riparian Buffers (RBDE), IAGT worked to develop methodologies to
quantitatively and descriptively evaluate factors such as the cost of implementation
of various model approaches, technical capacity required for implementation of those
models, and the overall value of the model results for aiding in targeted decision
making at the local government level. The intended value of the models on assessing
water quality is to assist in evaluating land use programs and water quality improvement
projects.
The results of this body of work were presented at the Federally sponsored
Interagency Conference on Research in the Watersheds Conference (ICRW3) in Estes
Park, CO, and again
at the New York State GIS Conference in Liverpool, NY.
Variable Source Area Hydrology
IAGT purchased sensors and deployed them in the field to validate topographic
index based predictions of soils saturation and runoff potential. Topographic indices
were calculated across the watershed as a predictor of areas prone to saturation
overflow, and hence primary risk areas for runoff and as source areas for nutrient
and pollutant load contributions.
Export Coefficient Modeling
This relatively complex
model was adapted using ESRI model builder and implemented using both federally
available and locally available data. The results allow for a spatial distribution
of pollutant loading across a contributing watershed while preserving the modeled
total load at the outlet. This has important implications for identifying source
areas of pollution based on standardized watershed characteristics and conditions
that can be represented in GIS data.
Riparian Buffer Delineation Equation
This effort
involved using GIS datasets as numerical inputs for solving an equation that evaluates
the effectiveness of riparian zones across a watershed. The results show a relative
ranking of riparian areas based on their risks of contributing sediment (erosion
potential) and pollutants (nutrient runoff potential) to a receiving stream. The
work was presented at the AWRA Specialty Conference on Wetlands Ecosystems in Norfolk,
VA.