1、Designation: D5980 96 (Reapproved 2010)1Standard Guide forSelection and Documentation of Existing Wells for Use inEnvironmental Site Characterization and Monitoring1This standard is issued under the fixed designation D5980; the number immediately following the designation indicates the year oforigin
2、al adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1NOTEThe units statement in 1.5 was revised editorially in August 2010.1. Sco
3、pe1.1 This guide covers the use of existing wells for environ-mental site characterization and monitoring. It covers thefollowing major topics: criteria for determining the suitabilityof existing wells for hydrogeologic characterization andground-water quality monitoring, types of data required todo
4、cument the suitability of an existing well, and the relativeadvantages and disadvantages of existing large- and small-capacity wells.1.2 This guide should be used in conjunction with GuideD5730, that provides a general approach for environmental siteinvestigations.1.3 This guide does not specificall
5、y address design andconstruction of new monitoring or supply wells. Refer toPractices D5092 and D5787.1.4 This guide does not specifically address ground-watersampling procedures. Refer to Guide D5903.1.5 The values stated in SI units are to be regarded asstandard. No other units of measurement are
6、included in thisstandard.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 health practices and determine the applica-bility of regulatory limitations pri
7、or 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 guide cannot replace education orexperience and should be used in conjunction with professionaljudgment. Not all aspects of this guide may be applicabl
8、e in allcircumstances. This guide is not intended to represent orreplace the standard of care by which the adequacy of a givenprofessional service must be judged, nor should this guide beapplied without consideration of a projects many uniqueaspects. The word “Standard” in the title of this document
9、means only that the document has been approved through theASTM consensus process.2. Referenced Documents2.1 Pertinent guides addressing specific information neces-sary to utilize existing wells for hydrologic and water-qualitydata for environmental site characterization. A comprehensivelist of guide
10、s, standards, methods, practices, and terminology iscontained in Guide D5730. Other guidance documents cover-ing procedures for environmental site investigations withspecific objectives or in particular geographic settings may beavailable from federal, state, and other agencies or organiza-tions. Th
11、e appropriate agency or organization should becontacted to determine the availability and most current editionof such documents.2.2 ASTM Standards:2D653 Terminology Relating to Soil, Rock, and ContainedFluidsD4750 Test Method for Determining Subsurface LiquidLevels in a Borehole or Monitoring Well (
12、ObservationWell)3D5092 Practice for Design and Installation of Ground WaterMonitoring WellsD5254 Practice for Minimum Set of Data Elements toIdentify a Ground-Water SiteD5408 Guide for Set of Data Elements to Describe aGround-Water Site; Part OneAdditional IdentificationDescriptorsD5409 Guide for Se
13、t of Data Elements to Describe aGround-Water Site; Part TwoPhysical DescriptorsD5410 Guide for Set of Data Elements to Describe aGround-Water Site;Part ThreeUsage DescriptorsD5474 Guide for Selection of Data Elements for Ground-Water Investigations1This guide is under the jurisdiction ofASTM Committ
14、ee D18 on Soil and Rockand is the direct responsibility of Subcommittee D18.21 on Ground Water andVadose Zone Investigations.Current edition approved Aug. 1, 2010. Published September 2010. Originallyapproved in 1996. Last previous edition approved in 2004 as D598096(2004).DOI: 10.1520/D5980-96R10E0
15、1.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Withdrawn. The last approved version of this historical st
16、andard is referencedon www.astm.org.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.D5521 Guide for Development of Ground-Water Monitor-ing Wells in Granular AquifersD5730 Guide for Site Characterization for EnvironmentalPurposes Wit
17、h Emphasis on Soil, Rock, the Vadose Zoneand Ground WaterD5753 Guide for Planning and Conducting Borehole Geo-physical LoggingD5787 Practice for Monitoring Well ProtectionD5903 Guide for Planning and Preparing for a GroundwaterSampling EventD5978 Guide for Maintenance and Rehabilitation ofGround-Wat
18、er Monitoring WellsD5979 Guide for Conceptualization and Characterization ofGround-Water Systems3. Terminology3.1 DefinitionsExcept as noted below, all definitions arein accordance with Terminology D653:3.1.1 aquifer, na geologic formation, group of forma-tions, or part of a formation that is satura
19、ted and is capable ofproviding a significant quantity of water (see Practice D5092).3.1.2 monitoring well (observation well), na special welldrilled in a selected location for observing parameters such asliquid level or pressure changes or for collecting liquidsamples. The well may be cased or uncas
20、ed, but if cased, thecasing should have openings to allow flow of borehole liquidinto or out of the casing.3.1.3 observation well, nfor the purposes of this guide, anexisting well constructed for other purposes that is also used tomeasure water levels and to collect ground-water qualitysamples. Obse
21、rvation well may be referred to as “well” in thisguide.3.1.4 supply (production) well, nwell primarily installedfor public supply, irrigation, and industrial use. Supply wellsmay be used as an observation well.4. Significance and Use4.1 This guide describes a general approach for the use ofexisting
22、wells in environmental investigations with a primaryfocus on the subsurface and major factors affecting the surfaceand subsurface environment.4.2 Existing wells represent a valuable source of informa-tion for subsurface environmental investigations. Specific usesof existing wells include:4.2.1 Well
23、driller logs provide information on subsurfacelithology and major water-bearing units in an area. Existingwells can also offer access for downhole geophysical loggingfor stratigraphic and aquifer interpretations. Examples includenatural gamma logs in cased wells and an entire suite ofmethods in unca
24、sed bedrock wells (see Guide D5753). Thisinformation can assist in developing the preliminary concep-tual model of the site.4.2.2 Well tests using existing wells may provide informa-tion on the hydrologic characteristics of an aquifer.4.2.3 Monitoring of water levels in existing wells, providedthat
25、they are cased in the aquifer of interest, allow developmentof potentiometric maps and interpretations of ground-waterflow directions.4.2.4 Existing wells are the primary means by which re-gional drinking water quality is evaluated and monitored.4.2.5 Existing wells may assist in the mapping of cont
26、ami-nant plumes, and in ongoing monitoring of ground-waterquality changes at the site-specific level.4.3 Data from existing wells should only be used whencharacteristics of the well have been sufficiently documented todetermine that they satisfy criteria for the purpose for whichthe data are to be u
27、sed.5. General Considerations in Selection and Use ofExisting Wells5.1 Selection and use of existing wells should take place inthe context of a conceptual framework consisting of a descrip-tion of the system, including, as necessary, physical andcultural characteristics, such as climate, hydrology,
28、ecology,physiography, population, water use and land use, and hypoth-eses about processes of interest that occur within that system.A step-wise approach for conceptualization and characteriza-tion is a direct approach to develop the framework forHydrologic Systems as described in Kolm (1)4, (see Gui
29、deD5979). Conceptualization of hydrologic and regional ground-water quality systems can be formulated using the methodsoutlined in Alley (2). The framework is reviewed and refinedby an iterative process of data collection and analysis, testinghypotheses with data collected, and identifying data need
30、s tofurther revise the framework. Refinement must be made withinthe limits established by the accuracy, precision, and complete-ness of the data. Methods for data collection are selected thatwill provide data appropriate for testing hypotheses whichevaluate the conceptual framework.5.2 Well design a
31、nd installation can critically affect thequality of water level measurements and ground-watersamples. Such effects apply both to existing wells and to wellsspecifically installed for a purpose. The effects of well designand installation, therefore, need to be considered regardless ofwhether existing
32、 wells are selected or if wells are specificallyinstalled for a specific purpose. The most common feature of anexisting well that may render it unsuitable for water levelmeasurement or water-quality monitoring is that multiplehydrogeologic units are connected causing water levels andwater-quality pa
33、rameters to reflect a mixing of multiple hydro-geologic units. Such data cannot be reliably compared withdata from wells completed in the individual hydrogeologicunits.5.3 Major steps in the selection of existing wells forenvironmental investigations include: developing specific cri-teria for evalua
34、ting the suitability of existing wells in relationto the objectives of the investigations (see Section 6), conduct-ing an inventory of existing wells in the area of interest (see8.1), documenting the characteristics of the wells identified inthe inventory that are relevant to the selection criteria
35、(see 8.2),and identification of wells that satisfy the selection criteria (seeSection 9).4The boldface numbers in parentheses refer to the list of references at the end ofthis standard.D5980 96 (2010)126. Well-Selection Criteria6.1 Assessing the suitability of existing wells for hydrologi-cal and gr
36、ound-water quality studies requires development ofspecific well-selection criteria. The criteria are based onconsiderations of project objectives by defining the problem tobe solved, the conceptual framework, and data-collectionrequirements.6.2 Specific Well-Selection CriteriaSpecific criteria willd
37、epend on the objectives of the investigation. The followinggeneral criteria will apply to most situations:6.2.1 The well is suitably located for use in relation to theconceptual framework.6.2.2 The well must be completed in the targeted hydrogeo-logic unit or units.6.2.3 Well design and construction
38、 must not bias water levelmeasurements or water-quality sampling results (see Note 1).Section 7 provides information on the general characteristics ofmajor types of existing wells.NOTE 1Gillham et al. (3), provides information on the suitability ofmaterials coming in contact with water samples and t
39、hat table providesinformation on the compatibility of well casing materials with differentorganic contaminants.6.2.4 The well is accessible for measurements and sam-pling.6.2.5 The wells maintenance condition may not compro-mise it as a sampling point; however, there are examples thatmay compromise
40、it as a sampling point, that is, a crackedcasing allowing non-screened water into the well.6.3 Examples of Well Selection CriteriaThe following areillustrative examples of criteria for specific investigation ob-jectives (see Note 2).NOTE 2These are illustrative examples and should not be construedas
41、 recommended criteria.6.3.1 A project to determine the quality of potable groundwater might require the following selection criteria: wellsselected must be used for public water supply, must begeographically distributed over the entire aquifer of interest,and must be able to be sampled prior to any
42、water treatment.6.3.2 All wells or a subset of wells down-gradient from ahazardous-waste site would be unsuitable to include in anetwork designed for a study to determine non-point sourceground-water quality.6.3.3 Choosing a well located down-gradient of a complexmix of land uses would be inappropri
43、ate in a study designed toassess the effects of specific land uses on ground-water quality.6.3.4 A supply well screened over a long interval would notbe appropriate for investigating small-scale vertical variationsin water quality down-gradient of a landfill, or for potentio-metric mapping.6.3.5 A w
44、ell constructed of PVC (polyvinylchloride) withglued joints would not be suitable for sampling if the volatile-organic compounds of interest in the ground water also arefound in the glue used to join the sections of well casing.Similarly, a well constructed of steel may not be suitable forthe sampli
45、ng of metals.6.3.6 Selecting an observation well in an area undergoingrapid development would be avoided in constructing a networkof wells for evaluating long-term trends in ground-waterquality because of the possibility of the well being destroyedby later development.7. General Characteristics of M
46、ajor Types of ExistingWells7.1 There are two general categories of existing wellsavailable for hydrologic and ground-water quality studies:large- and small-capacity supply or production wells installedfor drinking, irrigation, and industrial use (see 7.2 and 7.3); andwells specially designed and ins
47、talled to monitor hydrologic orwater-quality studies, or both (see 7.4). Each type of well hasits own general advantages and disadvantages.7.2 Large-Capacity Supply WellsLarge-capacity supplywells are usually developed for drinking water systems thatsupply multiple households, and for irrigation and
48、 industrialpurposes.7.2.1 Advantages:7.2.1.1 Documentation of well construction commonly isgood.7.2.1.2 Large-capacity wells generally are well developedand fully purged.7.2.1.3 Long-term access may be possible, particularly formunicipal wells.7.2.1.4 Large-capacity wells generally provide a larger
49、ver-tical mix of water in an aquifer or aquifer system thansmall-capacity wells, and thus can provide a more integratedmeasure of regional ground-water quality than small-capacitywells.7.2.1.5 Much of the water produced for irrigation andmunicipal water is from large-capacity wells equipped withtaps which allow a direct sample of the pumped water.7.2.1.6 Long-term water-quality and quantity data may beavailable.7.2.2 Disadvantages:7.2.2.1 Large-capacity wells may not have flow-rate con-trols and a sampling point near the well head.7.2.2.2 High pumping rates may ent
