ASTM_D_5850_-_95_2012.pdf

Designation:D585095(Reapproved 2012)Standard Test Method for(Analytical Procedure)Determining Transmissivity,Storage Coefficient,andAnisotropy Ratio from a Network of Partially PenetratingWells1This standard is issued under the fixed designation D5850;the number immediately following the designation indicates the year oforiginal 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.1.Scope1.1 This test method covers an analytical procedure fordetermining the transmissivity,storage coefficient,and ratio ofvertical to horizontal hydraulic conductivity of a confinedaquifer using observation well drawdown measurements froma constant-rate pumping test.This test method uses data froma minimum of four partially penetrating,properly positionedobservation wells around a partially penetrating control well.1.2 The analytical procedure is used in conjunction with thefield procedure in Test Method D4050.1.3 LimitationsThe limitations of the technique for deter-mination of the horizontal and vertical hydraulic conductivityof aquifers are primarily related to the correspondence betweenthe field situation and the simplifying assumption of this testmethod.1.4 The values stated in inch-pound units are to be regardedas the standard.The SI units given in parentheses are forinformation only.1.5 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 ContainedFluidsD4050 Test Method for(Field Procedure)for Withdrawaland Injection Well Testing for Determining HydraulicProperties of Aquifer SystemsD5473 Test Method for(Analytical Procedure for)Analyz-ing the Effects of Partial Penetration of Control Well andDetermining the Horizontal and Vertical Hydraulic Con-ductivity in a Nonleaky Confined Aquifer3.Terminology3.1 Definitions:3.1.1 aquifer,confinedan aquifer bounded above and be-low by confining beds and in which the static head is above thetop of the aquifer.3.1.2 confining beda hydrogeologic unit of less permeablematerial bounding one or more aquifers.3.1.3 control wellwell by which the head and flow in theaquifer is changed,for example,by pumping,injection,orimposing a constant change of head.3.1.4 drawdownvertical distance the static head is low-ered due to the removal of water.3.1.5 hydraulic conductivity(field aquifer test)the volumeof water at the existing kinematic viscosity that will move in aunit time under a unit hydraulic gradient through a unit areameasured at right angles to the direction of flow.3.1.6 observation wella well open to all or part of anaquifer.3.1.7 piezometera device so constructed and sealed as tomeasure hydraulic head at a point in the subsurface.3.1.8 storage coeffcientthe volume of water an aquiferreleases from or takes into storage per unit surface area of theaquifer per unit change in head.3.1.9 transmissivitythe volume of water at the existingkinematic viscosity that will move in a unit time under a unithydraulic gradient through a unit width of the aquifer.3.1.10 For definitions of other terms used in this testmethod,see Terminology D653.3.2 Symbols and Dimensions:3.2.1 AKz/Kr,anisotropy ratio nd.3.2.2 bthickness of aquifer L.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 May 1,2012.Published December 2012.Originallyapproved in 1995.Last previous edition approved in 2006 as D5850 95(2006).DOI:10.1520/D5850-95R12.2For 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.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 3.2.3 Cfdrawdown correction factor,equal to the ratio ofthe drawdown for a fully penetrating well network to thedrawdown for a partially penetrating well network(W(u)/(W(u)+fs).3.2.4 ddistance from top of aquifer to top of screenedinterval of control well L.3.2.5 ddistance from top of aquifer to top of screenedinterval of observation well L.3.2.6 fsincremental dimensionless drawdown componentresulting from partial penetration nd.3.2.7 Khydraulic conductivity LT1.3.2.7.1 DiscussionThe use of symbol K for the termhydraulic conductivity is the predominant usage in groundwa-ter literature by hydrogeologists,whereas the symbol k iscommonly used for this term in the rock and soil mechanicsliterature.3.2.8 Komodified Bessel function of the