ASTM_D_6642_-_01_2006.pdf

Designation:D664201(Reapproved2006)Standard Guide forComparison of Techniques to Quantify the Soil-Water(Moisture)Flux1This standard is issued under the fixed designation D6642;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 guide describes techniques that may be used toquantify the soil-water(or soil-moisture)flux,the soil-watermovement rate,and/or the recharge rate within the vadosezone.This guide is not intended to be all-inclusive with regardto available methods.However,the techniques described dorepresent the most widely used methods currently available.1.2 This guide was written to detail the techniques availablefor quantifying soil-moisture flux in the vadose zone.Thesedata are commonly required in studies of contaminant move-ment and in estimating the amount of water replenishing arenewable groundwater resource,that is,an aquifer.State andfederal regulatory guidelines typically require this informationin defining contaminant travel times,in performanceassessment,and in risk assessment.Both unsaturated andsaturated flow modelers benefit from these data in establishingboundary conditions and for use in calibrations of theircomputer simulations.1.3 This guide is one of a series of standards on vadose zonecharacterization methods.Other standards have been preparedon vadose zone characterization techniques.1.4 This guide offers an organized collection of informationor a series of options and does not recommend a specificcourse of action.This document cannot replace education orexperience and should be used in conjunction with professionaljudgment.Not all aspects of this guide may be applicable in allcircumstances.This ASTM standard is not intended to repre-sent or replace the standard of care by which the adequacy ofa given professional service must be judged,nor should thisdocument be applied without consideration of a projects manyunique aspects.The word“Standard”in the title of thisdocument means only that the document has been approvedthrough the ASTM consensus process.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 requirements prior to use.2.Referenced Documents2.1 ASTM Standards:2D653 Terminology Relating to Soil,Rock,and ContainedFluidsD1452 Practice for Soil Exploration and Sampling by AugerBoringsD2216 Test Methods for Laboratory Determination of Water(Moisture)Content of Soil and Rock by MassD3404 Guide for Measuring Matric Potential in VadoseZone Using TensiometersD4643 Test Method for Determination of Water(Moisture)Content of Soil by Microwave Oven HeatingD4696 Guide for Pore-Liquid Sampling from the VadoseZoneD4700 Guide for Soil Sampling from the Vadose ZoneD4944 Test Method for Field Determination of Water(Mois-ture)Content of Soil by the Calcium Carbide Gas PressureTesterD5126 Guide for Comparison of Field Methods for Deter-mining Hydraulic Conductivity in Vadose ZoneD5220 Test Method for Water Mass per Unit Volume of Soiland Rock In-Place by the Neutron Depth Probe Method3.Terminology3.1 Definitions:3.1.1 chlorine-36,36Cla radioactive isotope of chlorine,containing one extra neutron in the nucleus,and a decayhalf-life of 300,000 years.3.1.2 deuterium,2Ha stable isotope of hydrogen,contain-ing one extra neutron in the nucleus.3.1.3 oxygen-18,18Oa stable isotope of oxygen,contain-ing two extra neutrons in the nucleus.1This guide is under the jurisdiction ofASTM Committee D18 on Soil and Rockand is the direct responsibility of Subcommittee D18.21 on Groundwater andVadose Zone Investigations.Current edition approved July 1,2006.Published July 2006.Originally approvedin 2001.Last previous edition approved in 2001 as D6642 01.DOI:10.1520/D6642-01R06.2For 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 StatesNOTICE:This standard has either been superseded and replaced by a new version or withdrawn.Contact ASTM International(www.astm.org)for the latest information13.1.4 recharge flux,(LT1)the soil-moisture flux of watermoving through the vadose zone,beneath the zone of evapo-transpirative uptake,which eventually replenishes water to anunderlying aquifer.3.1.5 soil-moisture flux,(LT1)synonymous with specificdischarge.3.1.6 specific discharge,(LT1)the rate of flow of waterthrough a porous medium per unit area measured at a rightangle to the direction of flo