ASTM_D_6025_-_96_2008.pdf

Designation:D602596(Reapproved 2008)Standard Guide forDeveloping and Evaluating Groundwater Modeling Codes1This standard is issued under the fixed designation D6025;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 a systematic approach to thedevelopment,testing,evaluation,and documentation ofgroundwater modeling codes.The procedures presented con-stitute the quality assurance framework for a groundwatermodeling code.They include code review,testing,and evalu-ation using quantitative and qualitative measures.This guideapplies to both the initial development and the subsequentmaintenance and updating of groundwater modeling codes.1.2 When the development of a groundwater modeling codeis initiated,procedures are formulated to ensure that the finalproduct conforms with the design objectives and specificationsand that it correctly performs the incorporated functions.Theseprocedures cover the formulation and evaluation of the codestheoretical foundation and code design criteria,the applicationof coding standards and practices,and the establishment of thecodes credentials through review and systematic testing of itsfunctional design and through evaluation of its performancecharacteristics.1.3 The codes functionality needs to be defined in sufficientdetail for potential users to assess the codes utility as well asto enable the code developers to design a meaningful codetesting strategy.Comprehensive testing of a codes function-ality and performance is accomplished through a variety of testmethods.Determining the importance of the tested functionsand the ratio of tested versus non-tested functions provides anindication of the completeness of the testing.1.4 Groundwater modeling codes are subject to the softwarelife cycle concept that consists of a design phase,a develop-ment phase,and an operational phase.During the operationalphase the software is maintained,evaluated regularly,andchanged as additional requirements are identified.Therefore,quality assurance procedures should not only be established forsoftware design,programming,testing,and use,but also forcode maintenance and updating.1.5 Quality assurance in the development of groundwatermodeling codes cannot guarantee acceptable quality of thecode or a groundwater modeling study in which the code hasbeen used.However,adequate quality assurance can providesafeguards against the use in a modeling study of faulty codesor incorrect theoretical considerations and assumptions.Furthermore,there is no way to guarantee that modeling-basedadvice is entirely correct,nor that the groundwater model usedin the preparation of the advice(or any scientific model ortheory,for that matter)can ever be proven to be entirelycorrect.Rather,a model can only be invalidated by disagree-ment of its predictions with independently derived observa-tions of the studied system because of incorrect application ofthe selected code,the selection of an inappropriate code,theuse of an inadequately tested code,or invalidity of or errors inthe underlying theoretical framework.1.6 This guide is one of a series of guides on groundwatermodeling codes and their applications,such as Guides D5447,D5490,D5611,D5609,D5610,and D5718.Other standardshave been prepared on environmental modeling,such asPractice E978.1.7 Complete adherence to this guide may not always befeasible.If this guide is not integrally followed,the elements ofnoncompliance should be clearly identified and the reasons forthe partial compliance should be given.For example,partialcompliance might result from inadequacy of existing fieldtechniques for measuring relevant model parameters,specifi-cally in complex systems.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 this1This 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 1996 as D6025 96(2002).DOI:10.1520/D6025-96R08.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 document means only that the do