ASTM_D_4104_-_D_4104M_-_20.pdf

Designation:D4104/D4104M20Standard Practice for(Analytical Procedures)Determining Transmissivity ofNonleaky Confined Aquifers by Overdamped Well Responseto Instantaneous Change in Head(Slug Tests)1This standard is issued under the fixed designation D4104/D4104M;the number immediately following the designation indicates theyear of original adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of lastreapproval.A superscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope*1.1 This practice covers the determination of transmissivityfrom the measurement of force-free(overdamped)response ofa well-aquifer system to a sudden change of water level in awell.Force-free response of water level in a well to a suddenchange in water level is characterized by recovery to initialwater level in an approximate exponential manner with negli-gible inertial effects.1.2 The analytical procedure in this practice is used inconjunction with the field procedure in Test Method D4044/D4044M for collection of test data.1.3 LimitationsSlug tests are considered to provide anestimate of transmissivity.Although the assumptions of thispractice prescribe a fully penetrating well(a well open throughthe full thickness of the aquifer),the slug test is commonlyconducted using a partially penetrating well.Such a practicemay be acceptable for application under conditions in whichthe aquifer is stratified and horizontal hydraulic conductivity ismuch greater than vertical hydraulic conductivity.In such acase the test would be considered to be representative of theaverage hydraulic conductivity of the portion of the aquiferadjacent to the open interval of the well.1.4 All observed and calculated values shall conform to theguidelines for significant digits and rounding established inPractice D6026.1.4.1 The procedures used to specify how data are collected/recorded and calculated in the standard are regarded as theindustry standard.In addition,they are representative of thesignificant digits that generally should be retained.The proce-dures used do not consider material variation,purpose forobtaining the data,special purpose studies,or any consider-ations for the users objectives;and it is common practice toincrease or reduce significant digits of reported data to becommensurate with these considerations.It is beyond the scopeof this practice to consider significant digits used in analysismethods for engineering data.1.5 UnitsThe values stated in either SI units or inch-pound units are to be regarded separately as standard.Thevalues stated in each system may not be exact equivalents;therefore,each system shall be used independently of the other.Combining values from the two systems may result in noncon-formance with the standard.Reporting of results in units otherthan SI shall not be regarded as nonconformance with thisstandard.1.6 This practice offers a set of instructions for performingone or more specific operations.This document cannot replaceeducation or experience and should be used in conjunction withprofessional judgment.Not all aspects of the practice may beapplicable in all circumstances.This ASTM standard is notintended to represent or replace the standard of care by whichthe adequacy of a given professional service must be judged,nor should this document be applied without the considerationof a projects many unique aspects.The word“Standard”in thetitle of this document means only that the document has beenapproved through the ASTM consensus process.1.7 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,health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.8 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade(TBT)Committee.1This practice is under the jurisdiction of ASTM Committee D18 on Soil andRock and is the direct responsibility of Subcommittee D18.21 on Groundwater andVadose Zone Investigations.Current edition approved June 1,2020.Published June 2020.Originallyapproved in 1991.Last previous edition approved in 2017 as D4104 17.DOI:10.1520/D4104_D4104M-20.*A Summary of Changes section appears at the end of this standardCopyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade(