Title: | Evaluating Nonpoint-Source Critical Source Area Contributions at the Watershed Scale |
Authors: | White, M.J., D.E. Storm, P.R. Busteed, S.H. Stoodley, and S.J. Phillips |
Year: | 2009 |
Journal: | Journal of Environmental Quality |
Volume (Issue): | 38 |
Pages: | 1654-1663 |
Article ID: | |
DOI: | 10.2134/jeq2008.0375 |
URL (non-DOI journals): | |
Model: | SWAT |
Broad Application Category: | pollutant only |
Primary Application Category: | critical source area assessment |
Secondary Application Category: | pollutant cycling/loss and transport |
Watershed Description: | Six watersheds in different Oklahoma regions ranging from 230 to 1970 km^2 in size (see Tables 1 and 2) |
Calibration Summary: | |
Validation Summary: | |
General Comments: | |
Abstract: | critical source areas [CSAs]) have been widely recognized as
priority areas for the control of nonpoint-source pollution. Th e
identifi cation and evaluation of CSAs at the watershed scale
allows state and federal programs to implement soil and water
conservation measures where they are needed most. Despite
many potential advantages, many state and federal conservation
programs do not actively target CSAs. Th ere is a lack of
research identifying the total CSA pollutant contribution at
the watershed scale, and there is no quantitative assessment
of program eff ectiveness if CSAs are actively targeted. Th e
purpose of this research was to identify and quantify sediment
and total phosphorus loads originating from CSAs at the
watershed scale using the Soil and Water Assessment Tool. Th is
research is a synthesis of CSA targeting studies performed in
six Oklahoma priority watersheds from 2001 to 2007 to aid
the Oklahoma Conservation Commission in the prioritized
placement of subsidized conservation measures. Within these
six watersheds, 5% of the land area yielded 50% of sediment
and 34% of the phosphorus load. In watersheds dominated by
agriculture, the worst 5% of agricultural land contributed, on
average, 22% of the total agricultural pollutant load. Pollutant
loads from these agricultural CSAs were more than four times
greater than the average load from agricultural areas within the
watershed. Conservation practices implemented in these areas
can be more eff ective because they have the opportunity to
treat more pollutant. Th e evaluation of CSAs and prioritized
implementation of conservation measures at the watershed
scale has the potential to signifi cantly improve the eff ectiveness
of state and federally sponsored water quality programs. |
Language: | English |
Keywords: | |