Ground Water Vulnerability Assessment Predicting Relative Contamination Potential Under Conditions of Uncertainty (1993) / Chapter Skim
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6 Conclusions and Recommendations
6 Conclusions and Recommendations
Pages 170-180
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From page 170... ...
The chapter includes advice to policy makers and managers seeking to apply vulnerability assessments in ground water protection programs and a research agenda that suggests promising directions for improved understanding of the process of ground water contamination and the prediction of vulnerability to contamination. First Law of Ground Water Vulnerability: All ground water is vulnerable.
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From page 171... ...
This report distinguishes between two types of ground water vulnerability: intrinsic vulnerability, which reflects properties that are a function of the natural setting and does not consider the attributes and behavior of particular contaminants, and specific vulnerability, which reflects factors that relate to the properties of the specific constituents of concern, and possibly specific circumstances of land and chemical use (Chapter 1~. Using vulnerability assessments currently available, it is fairly easy to delineate many areas of high vulnerability, difficult to say for certain that an area has very low vulnerability, and not possible to make fine gradations in between.
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From page 172... ...
In the context of differential management of ground water with its goal of efficient use of resources policy makers, resource managers, and land users, would use vulnerability assessments as a tool in adjusting regulatory requirements and management practices for different areas and allocating program resources. For example, regulatory requirements and man
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From page 173... ...
None of these methods, even process-based models, can be validated in the usual scientific sense for vulnerability assessments because of spatial and temporal variability. This uncertainty in the ability to estimate the likelihood of future contamination will persist in the absence of noninvasive techniques for characterizing soil and ground water systems in three dimensions with respect to the parameters that affect contaminant movement through soil and the vadose zone.
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From page 174... ...
Standard national databases of good quality and understandable content are essential to ground water resource assessment and protection. The other major constraint on assessment of ground water vulnerability is the lack of digital spatial databases, particularly at the county, watershed, and field levels.
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From page 175... ...
software in recent years, digital information arising from vulnerability assessments can be easily displayed on a very sophisticated map without displaying the actual quality of the assessment. Innovation by the user and GIS industry, associated with improved assessment methodologies and uncertainty analyses, will prove most useful for depicting uncertainties associated with the vulnerability assessments portrayed on these same maps.
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From page 176... ...
At present, soil surveys contain large amounts of information that can be used in vulnerability assessments, but very few data exist on the hydrologic, geochemical, and microbial properties of the intermediate vadose zone (the unsaturated zone below the root zone)
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From page 177... ...
Establish reliable transfer functions for estimating in situ hydraulic properties, using available soil attribute data (e.g., bulk densities, particle-size distributions, etch. Develop ways to determine the additional uncertainty arising from the use of transfer functions in ground water vulnerability assessments.
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From page 178... ...
To determine ground water vulnerability accurately, the dominant processes at a given scale need to be identified and methods developed for characterizing them that can be used in modeling approaches. Obtain more information on the uncertainty associated with vulnerability assessments and develop ways to display this uncertainty.
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From page 179... ...
Likewise, some low-permeability materials overlying aquifers may transmit contaminants more easily than commonly perceived because of interconnected fracture systems. These counterintuitive situations typically would not be explicitly characterized in vulnerability assessments, generally because of the simplicity of current methods.
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