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Setting Priorities for Research on Pollution Reduction Functions of Agricultural Buffers 总被引:4,自引:0,他引:4
Dosskey MG 《Environmental management》2002,30(5):0641-0650
The success of buffer installation initiatives and programs to reduce nonpoint source pollution of streams on agricultural
lands will depend the ability of local planners to locate and design buffers for specific circumstances with substantial and
predictable results. Current predictive capabilities are inadequate, and major sources of uncertainty remain. An assessment
of these uncertainties cautions that there is greater risk of overestimating buffer impact than underestimating it.
Priorities for future research are proposed that will lead more quickly to major advances in predictive capabilities. Highest
priority is given for work on the surface runoff filtration function, which is almost universally important to the amount
of pollution reduction expected from buffer installation and for which there remain major sources of uncertainty for predicting
level of impact. Foremost uncertainties surround the extent and consequences of runoff flow concentration and pollutant accumulation.
Other buffer functions, including filtration of groundwater nitrate and stabilization of channel erosion sources of sediments,
may be important in some regions. However, uncertainty surrounds our ability to identify and quantify the extent of site conditions
where buffer installation can substantially reduce stream pollution in these ways.
Deficiencies in predictive models reflect gaps in experimental information as well as technology to account for spatial heterogeneity
of pollutant sources, pathways, and buffer capabilities across watersheds. Since completion of a comprehensive watershed-scale
buffer model is probably far off, immediate needs call for simpler techniques to gage the probable impacts of buffer installation
at local scales. 相似文献
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Toward quantifying water pollution abatement in response to installing buffers on crop land 总被引:7,自引:0,他引:7
Dosskey MG 《Environmental management》2001,28(5):577-598
The scientific research literature is reviewed (i) for evidence of how much reduction in nonpoint source pollution can be
achieved by installing buffers on crop land, (ii) to summarize important factors that can affect this response, and (iii)
to identify remaining major information gaps that limit our ability to make probable estimates. This review is intended to
clarify the current scientific foundation of the USDA and similar buffer programs designed in part for water pollution abatement
and to highlight important research needs.
At this time, research reports are lacking that quantify a change in pollutant amounts (concentration and/or load) in streams
or lakes in response to converting portions of cropped land to buffers. Most evidence that such a change should occur is indirect,
coming from site-scale studies of individual functions of buffers that act to retain pollutants from runoff: (1) reduce surface
runoff from fields, (2) filter surface runoff from fields, (3) filter groundwater runoff from fields, (4) reduce bank erosion,
and (5) filter stream water. The term filter is used here to encompass the range of specific processes that act to reduce pollutant amounts in runoff flow.
A consensus of experimental research on functions of buffers clearly shows that they can substantially limit sediment runoff
from fields, retain sediment and sediment-bound pollutants from surface runoff, and remove nitrate N from groundwater runoff.
Less certain is the magnitude of these functions compared to the cultivated crop condition that buffers would replace within
the context of buffer installation programs. Other evidence suggests that buffer installation can substantially reduce bank
erosion sources of sediment under certain circumstances. Studies have yet to address the degree to which buffer installation
can enhance channel processes that remove pollutants from stream flow.
Mathematical models offer an alternative way to develop estimates for water quality changes in response to buffer installation.
Numerous site conditions and buffer design factors have been identified that can determine the magnitude of each buffer function.
Accurate models must be able to account for and integrate these functions and factors over whole watersheds. At this time,
only pollutant runoff and surface filtration functions have been modeled to this extent. Capability is increasing as research
data is produced, models become more comprehensive, and new techniques provide means to describe variable conditions across
watersheds.
A great deal of professional judgment is still required to extrapolate current knowledge of buffer functions into broadly
accurate estimates of water pollution abatement in response to buffer installation on crop land. Much important research remains
to be done to improve this capability. The greatest need is to produce direct quantitative evidence of this response. Such
data would confirm the hypothesis and enable direct testing of watershed-scale prediction models as they become available.
Further study of individual pollution control functions is also needed, particularly to generate comparative evidence for
how much they can be manipulated through buffer installation and management. 相似文献
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