ASTM_D_5981_-_D_5981M_-_18.pdf

Designation:D5981/D5981M18Standard Guide forCalibrating a Groundwater Flow Model Application1This standard is issued under the fixed designation D5981/D5981M;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 guide covers techniques that can be used tocalibrate a groundwater flow model.The calibration of a modelis the process of matching historical data,and is usually aprerequisite for making predictions with the model.1.2 Calibration is one of the stages of applying a ground-water modeling code to a site-specific problem(see GuideD5447).Calibration is the process of refining the modelrepresentation of the hydrogeologic framework,hydraulicproperties,and boundary conditions to achieve a desireddegree of correspondence between the model simulations andobservations of the groundwater flow system.1.3 Flow models are usually calibrated using either themanual(trial-and-error)method or an automated(inverse)method.This guide presents some techniques for calibrating aflow model using either method.1.4 This guide is written for calibrating saturated porousmedium(continuum)groundwater flow models.However,these techniques,suitably modified,could be applied to othertypes of related groundwater models,such as multi-phasemodels,non-continuum(karst or fracture flow)models,ormass transport models.1.5 Guide D5447 presents the steps to be taken in applyinga groundwater modeling code to a site-specific problem.Calibration is one of those steps.Other standards have beenprepared on environmental modeling,such as Guides D5490,D5609,D5610,D5611,D5718,and Practice E978.1.6 UnitsThe values stated in either SI units or inch-pound units(given in brackets)are to be regarded separately asstandard.The values stated in each system may not be exactequivalents;therefore,each system shall be independently ofthe other.Combining values from the two systems may resultin non-conformance with the standard.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,health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.8 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.1.9 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade(TBT)Committee.2.Referenced Documents2.1 ASTM Standards:2D653 Terminology Relating to Soil,Rock,and ContainedFluidsD5447 Guide for Application of a Numerical GroundwaterFlow Model to a Site-Specific ProblemD5490 Guide for Comparing Groundwater Flow ModelSimulations to Site-Specific InformationD5609 Guide for Defining Boundary Conditions in Ground-water Flow ModelingD5610 Guide for Defining Initial Conditions in GroundwaterFlow ModelingD5611 Guide for Conducting a Sensitivity Analysis for aGroundwater Flow Model ApplicationD5718 Guide for Documenting a Groundwater Flow ModelApplication1This 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 Jan.1,2018.Published February 2018.Originallyapproved in 1996.Last previous edition approved in 2002 as D5981 96(2008),which was withdrawn January 2017 and reinstated in January 2018.DOI:10.1520/D5981_D5981M-18.2For 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 StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Pr