ASTM_D_5981_-_96_2008.pdf

Designation:D598196(Reapproved 2008)Standard Guide forCalibrating a Groundwater Flow Model Application1This standard is issued under the fixed designation D5981;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 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 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.1.7 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 forApplication of a Groundwater Flow Modelto a Site-Specific ProblemD5490 Guide for Comparing Ground-Water 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 aGround-Water Flow Model ApplicationD5718 Guide for Documenting a Groundwater Flow ModelApplicationE978 Practice for Evaluating Mathematical Models for theEnvironmental Fate of Chemicals(Withdrawn 2002)33.Terminology3.1 Definitions:3.1.1 application verificationusing the set of parametervalues and boundary conditions from a calibrated model toapproximate acceptably a second set of field data measuredunder similar hydrologic conditions.3.1.1.1 DiscussionApplication verification is to be distin-guished from code verification,which refers to softwaretesting,comparison with analytical solutions,and comparison1This 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 November 2008.Originallyapproved in 1996.Last previous edition approved in 2002 as D5981 96(2002).DOI:10.1520/D5981-96R08.2For 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.3The last approved version of this historical standard is referenced onwww.astm.org.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 with other similar codes to demonstrate that the code representsits mathematical foundations.3.1.2 calibrated modela model that has achieved a desireddegree of correspondence between the model simulations andobservations of the physical hydrogeologic system.3.1.3 calibration(model application)the process of refin-ing the model representation of the h