1、Designation: D 6030 96 (Reapproved 2002)Standard Guide forSelection of Methods for Assessing Ground Water orAquifer Sensitivity and Vulnerability1This standard is issued under the fixed designation D 6030; the number immediately following the designation indicates the year oforiginal adoption or, in
2、 the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This guide covers information needed to select one ormore methods for assessing th
3、e sensitivity of ground water oraquifers and the vulnerability of ground water or aquifers towater-quality degradation by specific contaminants.1.2 This guide may not be all-inclusive; it offers a series ofoptions and does not specify a course of action. It should not beused as the sole criterion or
4、 basis of comparison, and does notreplace professional judgment.1.3 This guide is to be used for evaluating sensitivity andvulnerability methods for purposes of land-use management,water-use management, ground-water protection, governmentregulation, and education. This guide incorporates description
5、sof general classes of methods and selected examples withinthese classes but does not advocate any particular method.1.4 LimitationsThe utility and reliability of the methodsdescribed in this guide depend on the availability, nature, andquality of the data used for the assessment; the skill, knowl-e
6、dge, and judgment of the individuals selecting the method; thesize of the site or region under investigation; and the intendedscale of resulting map products. Because these methods arebeing continually developed and modified, the results shouldbe used with caution. These techniques, whether or not t
7、heyprovide a specific numeric value, provide a relative rankingand assessment of sensitivity or vulnerability. However, arelatively low sensitivity or vulnerability for an area does notpreclude the possibility of contamination, nor does a highsensitivity or vulnerability necessarily mean that ground
8、 wateror an aquifer is contaminated.1.5 The values stated in SI units are to be regarded asstandard.1.6 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and heal
9、th practices and determine the applica-bility of regulatory limitations prior to use.1.7 This guide offers an organized collection of informationor a series of options and does not recommend a specificcourse of action. This document cannot replace education orexperience and should be used in conjunc
10、tion with professionaljudgment. Not all aspects of this guide may be applicable in allcircumstances. This ASTM standard is not intended to repre-sent or replace the standard of care by which the adequacy ofa given professional service must be judged, nor should thisdocument be applied without consid
11、eration of a projects manyunique aspects. The word “Standard” in the title of thisdocument means only that the document has been approvedthrough the ASTM consensus process.2. Referenced Documents2.1 ASTM Standards:D 653 Terminology Relating to Soil, Rock, and ContainedFluids2D 5447 Guide for Applica
12、tion of a Ground-Water FlowModel to a Site-Specific Problem2D 5490 Guide for Comparing Ground-Water Flow ModelSimulations to Site-Specific Information2D 5549 Guide for the Contents of Geostatistical Site Inves-tigation Report2D 5717 Guide for the Design of Ground-Water MonitoringSystems in Karst and
13、 Fractured-Rock Aquifers2D 5880 Guide for Subsurface Flow and Transport Model-ing33. Terminology3.1 DefinitionsMany of the terms discussed in this guideare contained in Terminology D 653. The reader should refer tothis guide for definitions of selected terms.3.1.1 ground-water region, nan extensive
14、area whererelatively uniform geology and hydrology controls groundwater movement.3.1.2 hydrogeologic setting, na composite description ofall the major geologic and hydrologic features which affect andcontrol ground-water movement into, through, and out of anarea (1).43.1.3 sensitivity, nin ground wa
15、ter, the potential forground water or an aquifer to become contaminated based on1This guide is under the jurisdiction of ASTM Committee D18 on Soil and Rockand is the direct responsibility of Subcommittee D18.21 on Ground Water andVadose Zone Investigations.Current edition approved Oct. 10, 1996. Pu
16、blished May 1997.2Annual Book of ASTM Standards, Vol 04.08.3Annual Book of ASTM Standards, Vol 04.09.4The boldface numbers in parentheses refer to a list of references at the end ofthis guide.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United
17、States.intrinsic hydrogeologic characteristics. Sensitivity is not de-pendent on land-use practices or contaminant characteristics.Sensitivity is equivalent to the term 88intrinsic ground-watervulnerability” (2).3.1.3.1 DiscussionHydrogeologic characteristics includethe natural properties of the soi
18、l zone, unsaturated zone, andsaturated zone.3.1.4 vulnerability, nin ground water, the relative easewith which a contaminant can migrate to ground water or anaquifer of interest under a given set of land-use practices,contaminant characteristics, and sensitivity conditions. Vulner-ability is equival
19、ent to 88specific ground-water vulnerability.”4. Significance and Use4.1 Sensitivity and vulnerability methods can be applied toa variety of hydrogeologic settings, whether or not they containspecifically identified aquifers. However, some methods arebest suited to assess ground water within aquifer
20、s, while othersassess ground water above aquifers or ground water in areaswhere aquifers have not been identified.4.1.1 Intergranular media systems, including alluvium andterrace deposits, valley fill aquifers, glacial outwash, sand-stones, and unconsolidated coastal plain sediments are charac-teriz
21、ed by intergranular flow, and thus generally exhibit slowerand more predictable ground-water velocities and directionsthan in fractured media. Such settings are amenable to assess-ment by the methods described in this guide. Hydrologicsettings dominated by fracture flow or flow in solution open-ings
22、 are generally not amenable to such assessments, andapplication of these techniques to such settings may providemisleading or totally erroneous results.4.2 The methods discussed in this guide provide users withinformation for making land- and water-use managementdecisions based on the relative sensi
23、tivity or vulnerability ofunderlying ground water or aquifers to contamination. Mostsensitivity and vulnerability assessment methods are designedto evaluate broad regional areas for purposes of assistingfederal, state, and local officials to identify and prioritize areaswhere more detailed assessmen
24、ts are warranted, to design andlocate monitoring systems, and to help develop optimumground-water management, use and protection policies. How-ever, some of these methods are independent of the size of thearea evaluated and, therefore, can be used to evaluate theaquifer sensitivity and vulnerability
25、 of any specific area.4.3 Many methods for assessing ground-water sensitivityand vulnerability require information on soils, and for sometypes of potential ground-water contaminants, soil is the mostimportant factor affecting contaminant movement and attenu-ation from the land surface to ground wate
26、r. The relativelylarge surface area of the clay-size particles in most soils and thesoils content of organic matter provide sites for the retardationand degradation of contaminants. Unfortunately, there aresignificant differences in the definition of soil between thesciences of hydrogeology, enginee
27、ring, and agronomy. For thepurposes of this guide, soils are considered to be thoseunconsolidated organic materials and solid mineral particlesthat have been derived from weathering and are characterizedby significant biological activity. In the United States, thesetypically include unconsolidated m
28、aterials that occur to a depthof2to3mormore.4.3.1 In many areas, significant thicknesses of unconsoli-dated materials may occur below the soil. Retardation, degra-dation, and other chemical attenuation processes are typicallyless than in the upper soil horizons. These underlying materialsmay be the
29、result of depositional processes or may have formedin place by long-term weathering processes with only limitedbiological activity. Therefore, when compiling the data re-quired for assessing ground-water sensitivity and vulnerability,it is important to distinguish between the soil zone and theunderl
30、ying sediments and to recognize that the two zones havesignificantly different hydraulic and attenuation properties.5. Description of Methods5.1 Hydrogeologic Settings and Scoring MethodsThisgroup of methods includes those that involve geologic map-ping, evaluation, and scoring of hydrogeologic char
31、acteristicsto produce a composite sensitivity map or composite vulner-ability map, or both. The methods range from purely descrip-tive of hydrogeologic settings to methods incorporating nu-merical scoring. They can include descriptive information orquantitative information, or both, and the maps can
32、 be appliedas a “filter” to exclude specific hydrogeologic units fromfurther consideration or select sensitive areas for further study.5.1.1 The concept of assessing ground-water sensitivity andvulnerability is relatively recent and still developing. Thus, themethods presented differ because they ha
33、ve been developed fordifferent purposes by different researchers using various typesof data bases in several hydrogeologic settings. These methodshave been divided into three groups: assessments using hydro-geologic settings without scoring or rankings, assessments inwhich hydrogeologic setting info
34、rmation is combined withranking or scoring of hydrologic factors, and assessments usingscoring methods applied without reference to the hydrogeo-logic setting. The groups are not exclusive but overlap. Each ofthese methods produces relative, not absolute, results whetheror not it produces a numerica
35、l score. Sensitivity analyses canbe used as the basis for a vulnerability assessment by addingthe information on potential point and non-point contaminantsources.5.1.2 Hydrogeologic Settings, No Scoring or RankingHydrogeologic mapping has been widely used to provideaquifer sensitivity information. T
36、his subgroup of methodsincludes those that generally present information as compositehydrogeologic maps that can be used for multiple purposes.The maps can be used individually to make a variety ofland-use decisions or used as a basis for ground-water andaquifer sensitivity evaluations. Although der
37、ivative ground-water and aquifer sensitivity maps can be prepared, anygeologic or hydrogeologic map could potentially be used toassess sensitivity. In settings where quantitative data arelacking, hydrogeologic maps can allow the same conclusions,with the same level of confidence, as scoring methods.
38、 Hydro-geologic settings were mapped in detail without scoring orranking in the Denver Colorado, United States area by Hearneand others (3).5.1.2.1 Sensitivity assessments based on hydrogeologic set-tings with no scoring or ranking can be used to assessD 6030 96 (2002)2ground-water or aquifer vulner
39、ability by overlaying informa-tion on potential point or non-point contamination sources. Forexample, the sensitivity map included in Ref (3) has been usedin combination with a series of maps entitled “Land UsesWhich Affect Ground-Water Management” (4) to conductvulnerability assessments at specific
40、 sites within the greaterDenver area.5.1.3 Hydrogeologic Settings with Ranking or Scoring, orBothThis group of methods includes those which assessground-water or aquifer sensitivity within or among varioushydrogeologic settings using specific criteria to rank or scoreareas beneath which the ground w
41、ater or aquifers have differentpotentials for becoming contaminated. The assessment isusually based on two or more hydrogeologic criteria. Forexample, material texture and depth to aquifer are parametersthat are commonly used to establish criteria (5-10). Criteria,once defined, can then be ranked or
42、 scored, or both.5.1.3.1 Assessing vulnerability from point and non-pointsources of potential contamination (for example, leaking tanks,waste generators, landfills, and abandoned hazardous wastesites) is accomplished by mapping their location on a sensitiv-ity map (for example, numerous waste-genera
43、tion sites in anarea of low sensitivity would result in a relatively lowvulnerability rank, all other factors being equal). This mappingmethod is particularly useful for evaluating the vulnerability ofa large region. However, it can also be used to target smallerareas of particular concern where mor
44、e detailed investigationsmay be needed. For example, Shafer (11) mapped regionalaquifer vulnerability based on sensitivity analysis. Bhagwatand Berg (12) defined aquifer sensitivity according to depth toaquifers and the characteristics of the geologic materials. Thesensitivity map was combined with
45、information showing thedistribution of waste-source sites per zip code per square mile.Highly vulnerable areas have aquifers at or near the surface andcontain numerous point sources of potential contaminationwith mobile contaminants. Areas of low vulnerability havedeep ground water or no aquifers an
46、d contain few potentialcontaminant sources or relatively immobile contaminants. Thisvulnerability information was then used to establish ground-water protection planning regions.5.1.4 Scoring, Without Hydrogeologic SettingsThis cat-egory includes those methods that use qualitative ranking orquantita
47、tive scoring with hydrogeologic information, but with-out subdividing the area on the basis of hydrogeologic settings.Methods were developed to have universal application andwere intended to be used consistently to provide uniformresults regardless of location. The methods are useful forapplications
48、 that require a consistent approach over large areas,however, these methods can be complex and may require muchunnecessary data preparation. Furthermore, because criteriaselection and ranking are subjective, the final scores may bemisleading.5.1.4.1 These methods classify a site or region based on a
49、ranking or a numerical score derived from hydrogeologicalinformation irrespective of the different hydrogeologic settingsthat may be present within the mapped area. Scores arecalculated from equations based on criteria assumed to apply todifferent geographic areas and different hydrogeologic condi-tions (1,1314). For example, in South Dakota (15), drillinglogs and soil survey maps were used to prepare maps based onhydraulic conductivity which was inferred from the percentand thickness of surface organic matter. Attenuation potentialsof soil in selected Wisconsin counties (1
