ASTM_D_5855_-_D_5855M_-_15.pdf

Designation:D5855/D5855M15Standard Test Method for(Analytical Procedure)for Determining Transmissivity andStorage Coefficient of Confined Nonleaky or Leaky Aquiferby Constant Drawdown Method in Flowing Well1This standard is issued under the fixed designation D5855/D5855M;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 test method covers an analytical solution fordetermining transmissivity and storage coefficient of a leaky ornonleaky confined aquifer.It is used to analyze data on the flowrate from a control well while a constant head is maintained inthe well.1.2 This analytical procedure is used in conjunction with thefield procedure in Practice D5786.1.3 LimitationsThe limitations of this technique for thedetermination of hydraulic properties of aquifers are primarilyrelated to the correspondence between field situation and thesimplifying assumption of the solution.1.4 UnitsThe values stated in either SI units or inch-pound units are to be regarded separately as standard.Thevalues in each system may not be exact equivalents;thereforeeach system shall be used independently of the other.Combin-ing values from the two systems may result in non-conformance with the standard.Reporting of test results inunits other than SI shall not be regarded as nonconformancewith this test method.1.5 All observed and calculated values shall conform to theguidelines for significant digits and rounding established inPractice D6026.1.6 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 prior to use.2.Referenced Documents2.1 ASTM Standards:2D653 Terminology Relating to Soil,Rock,and ContainedFluidsD3740 Practice for Minimum Requirements for AgenciesEngaged in Testing and/or Inspection of Soil and Rock asUsed in Engineering Design and ConstructionD4043 Guide for Selection of Aquifer Test Method inDetermining Hydraulic Properties by Well TechniquesD5786 Practice for(Field Procedure)for Constant Draw-down Tests in Flowing Wells for Determining HydraulicProperties of Aquifer SystemsD6026 Practice for Using Significant Digits in GeotechnicalData3.Terminology3.1 Derfinitions:3.1.1 For definitions of terms used in this test method,seeTerminology D653.3.2 Symbols and Dimensions:3.2.1 Ttransmissivity L2T1.3.2.2 K1 modified Bessel function of the second kind,firstorder nd.3.2.3 K2 modified Bessel function of the second kind,zero order nd.3.2.4 J0 Bessel function of the first kind,zero order nd.3.2.5 Y0 Bessel function of the second kind,zero ordernd.3.2.6 W(u)w(well)function of u nd.3.2.7 uvariable of integration nd.1This test method is under the jurisdiction ofASTM Committee D18 on Soil andRock and is the direct responsibility of Subcommittee D18.21 on Groundwater andVadose Zone Investigations.Current edition approved Nov.1,2015.Published December 2015.Originallyapproved in 1995.Last previous edition approved in 2013 as D5855 95(2013).DOI:10.1520/D5855_D5855M-15.2For 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.*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 States1 3.2.8 telapsed time test T.3.2.9 Qdischarge rate L3T1.3.2.10 sWconstant drawdown in control well L.3.2.11 Sstorage coefficient nd.3.2.12 rWradius of control well.4.Summary of Test Method4.1 This test method describes the analytical procedure foranalyzing data collected during a constant drawdown aquifertest.This test method is usually performed on a flowing well.After the well has been shut-in for a period of time,the well isopened and the discharge rate is measured over a period of timeafter allowing the well to flow.The water level in the controlwell while the well is flowing is the elevation of the opening ofthe control well through which the water is allowed to flow.Data are analyzed by plotting the discharge rate versus time.NOTE1This test method involves the withdrawal of water from acontrol well that is fully screened through the confined aquifer.Thewithdrawal rate is varied to cause the water level within the well to remainconstant.The field procedure involved in conducting a constant drawdowntest is given in Practice D5786.Methods used to develop a conceptualmodel of the site and for initially selecting an analytical procedure aredescribed in Guide D4043.4.2 Leaky Aquifer SolutionThe solution is given by