ASTM_D_5609_-_94_2015e1.pdf

Designation:D560994(Reapproved 2015)1Standard Guide forDefining Boundary Conditions in Groundwater FlowModeling1This standard is issued under the fixed designation D5609;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.1NOTEReapproved with editorial changes in September 2015.1.Scope*1.1 This guide covers the specification of appropriateboundary conditions that are to be considered part of concep-tualizing and modeling groundwater systems.This guide de-scribes techniques that can be used in defining boundaryconditions and their appropriate application for modelingsaturated groundwater flow model simulations.1.2 This guide is one of a series of standards on groundwa-ter flow model applications.Defining boundary conditions is astep in the design and construction of a model that is treatedgenerally in Guide D5447.1.3 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.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.2.Referenced Documents2.1 ASTM Standards:2D653 Terminology Relating to Soil,Rock,and ContainedFluidsD5447 Guide for Application of a Groundwater Flow Modelto a Site-Specific Problem3.Terminology3.1 For common definitions of terms in this standard,referto Terminology D653.3.2 Definitions of Terms Specific to This Standard:3.2.1 aquifer,confinedan aquifer bounded above and be-low by confining beds and in which the static head is above thetop of the aquifer.3.2.2 boundarygeometrical configuration of the surfaceenclosing the model domain.3.2.3 boundary conditiona mathematical expression ofthe state of the physical system that constrains the equations ofthe mathematical model.3.2.4 conceptual modela simplified representation of thehydrogeologic setting and the response of the flow system tostress.3.2.5 fluxthe volume of fluid crossing a unit cross-sectional surface area per unit time.3.2.6 groundwater flow modelan application of a math-ematical model to the solution of a groundwater flow problem.3.2.7 hydraulic conductivity(field aquifer tests),the vol-ume of water at the existing kinematic viscosity that will movein a unit time under unit hydraulic gradient through a unit areameasured at right angles to the direction of flow.3.2.8 hydrologic conditiona set of groundwater inflows oroutflows,boundary conditions,and hydraulic properties thatcause potentiometric heads to adopt a distinct pattern.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 Sept.15,2008.Published October 2015.Originallyapproved in 1994.Last previous edition approved in 2008 as D5609 94(2008).DOI:10.1520/D5609-94R15E01.2For 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 3.2.9 simulationone complete execution of the computerprogram,including input and output.3.2.10 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.3.2.11 unconfined aquiferan aquifer that has a water table.4.Significance and Use4.1 Accurate definition of boundary conditions is an impor-tant part of conceptualizing and modeling groundwater flowsystems.This guide describes the properties of the mostcommon boundary conditions encountered in groundwatersystems and discusses major aspects of their definition andapplication in groundwater models.It also discusses thesignificance and specification of boundary conditions for somefield situations and some common errors in specifying bound-a