ASTM_D_5785_-_D_5785M_-_15.pdf

Designation:D5785/D5785M15Standard Test Method for(Analytical Procedure)for Determining Transmissivity ofConfined Nonleaky Aquifers by Underdamped WellResponse to Instantaneous Change in Head(Slug Test)1This standard is issued under the fixed designation D5785/D5785M;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 determination of transmissivityfrom the measurement of the damped oscillation about theequilibrium water level of a well-aquifer system to a suddenchange of water level in a well.Underdamped response ofwater level in a well to a sudden change in water level ischaracterized by oscillatory fluctuation about the static waterlevel with a decrease in the magnitude of fluctuation andrecovery to initial water level.Underdamped response mayoccur in wells tapping highly transmissive confined aquifersand in deep wells having long water columns.1.2 This analytical procedure is used in conjunction with thefield procedure Test Method D4044 for collection of test data.1.3 LimitationsSlug tests are considered to provide anestimate of transmissivity of a confined aquifer.This testmethod requires that the storage coefficient be known.As-sumptions of this test method prescribe a fully penetrating well(a well open through the full thickness of the aquifer),but theslug test method is commonly conducted using a partiallypenetrating well.Such a practice may be acceptable forapplication under conditions in which the aquifer is stratifiedand horizontal hydraulic conductivity is much greater thanvertical hydraulic conductivity.In such a case the test would beconsidered to be representative of the average hydraulicconductivity of the portion of the aquifer adjacent to the openinterval of the well.The method assumes laminar flow and isapplicable for a slug test in which the initial water-leveldisplacement is less than 0.1 or 0.2 of the length of the staticwater column.1.4 This test method of analysis presented here is derived byvan der Kamp(1)2based on an approximation of the under-damped response to that of an exponentially damped sinusoid.A more rigorous analysis of the response of wells to a suddenchange in water level by Kipp(2)indicates that the methodpresented by van der Kamp(1)matches the solution of Kipp(2)when the damping parameter values are less than about 0.2and time greater than that of the first peak of the oscillation(2).1.5 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.1.6 All observed and calculated values shall conform to theguidelines for significant digits and rounding established inPractice D6026.1.7 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 and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:3D653 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 TechniquesD4044 Test Method for(Field Procedure)for InstantaneousChange in Head(Slug)Tests for Determining HydraulicProperties of AquifersD6026 Practice for Using Significant Digits in GeotechnicalData1This 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 November 2015.Originallyapproved in 1995.Last previous edition approved in 2013 as D5785 95(2013).DOI:10.1520/D5785_D5785M-15.2The boldface numbers given in parentheses refer to a list of references at theend of the text.3For 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.Terminology3.1 DefinitionsFor definitions of other terms used in thistest method,see Terminology D653.3.1.1 observati