ASTM D6025 - 96(2008) Standard Guide for Developing and Evaluating Groundwater Modeling Codes (Withdrawn 2017).pdf

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1、Designation: D6025 96 (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 la

2、st 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

3、 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

4、 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 formul

5、ation 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

6、 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 t

7、estmethods. 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 phas

8、e, 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 ma

9、intenance 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

10、 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

11、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 inval

12、idity 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

13、 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 fieldtec

14、hniques 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 conjunctio

15、n 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 considera

16、tion 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. Publ

17、ished 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 StatesNOTICE: This standard has either been superseded and re

18、placed by a new version or withdrawn.Contact ASTM International (www.astm.org) for the latest information1document 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 ContainedFluidsD

19、5447 Guide for Application of a Groundwater Flow Modelto 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 Groundwater

20、Flow ModelingD5611 Guide for Conducting a Sensitivity Analysis for aGroundwater 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:

21、3.1.1 code verification, n in groundwater modeling, theprocess of demonstrating the consistency, completeness,correctness, and accuracy of a groundwater modeling codewith respect to its design criteria by evaluating the functional-ity and operational characteristics of the code and testingembedded a

22、lgorithms and internal data transfers through ex-ecution of problems for which independent benchmarks areavailable (1).43.1.1.1 DiscussionIn software engineering, verification isthe process of demonstrating consistency, completeness, andcorrectness of the software (2). Practice E978 defines verifica

23、-tion as “.the examination of the numerical technique in thecomputer code to ascertain that it truly represents the concep-tual model and that there are no inherent problems withobtaining a solution.” In this guide, the term code verificationis used. The objective of the code verification process is

24、threefold: (1) to check the correctness of the program logic andthe computational accuracy of the algorithms used to solve thegoverning equations; (2) to ensure that the computer code isfully operational (no programming errors); and (3) to evaluatethe performance of the code with respect to all of i

25、ts designedand inherent functions (1).A code can be considered “verified” when all its functionsand operational characteristics have been tested and havemet specific performance criteria, established at the begin-ning of the verification procedure. Considering a codeverified does not imply that a gr

26、oundwater model applicationconstructed with the code is verified.NOTE 1In groundwater modeling, the term “validation” is sometimesused to describe the process of determining how well a groundwatermodeling codes theoretical foundation and computer implementationdescribe actual system behavior in term

27、s of the degree of correlationbetween calculated and independently observed cause-and-effect re-sponses of the reference groundwater system for which the code has beendeveloped (1,3). This process is also referred to as field demonstration,field comparison, or extended verification (4).NOTE 2Validat

28、ion as described in Note 1 is by nature a subjective andopen-ended process. As there is no practical way to determine that agroundwater modeling code correctly represents the reference system, thecode can never be considered “validated.” Therefore, this guide does notendorse the use of the term vali

29、dation in the context of groundwatermodeling (1,3,4).3.1.2 computer code (computer program), n the assemblyof numerical techniques, bookkeeping, and control languagethat represents a model from acceptance of input data andinstructions to delivery of output.3.1.3 functionality, n of a groundwater mod

30、eling code, theset of functions and features the code offers the user in terms ofmodel framework geometry, simulated processes, boundaryconditions, and analytical and operational capabilities.3.1.4 groundwater model application, n a nonunique,simplified mathematical description of one or more subsur

31、facecomponents of a local or regional hydrologic system, coded ina computer programing language, together with a quantifica-tion of the simulated system in the form of frameworkgeometry, boundary conditions, system and processparameters, and system stresses.3.1.4.1 DiscussionAs defined in 3.1.4, a g

32、roundwatermodel application is a representation of an actual hydrologicsystem; it should not be confused with the generic computercode used in formulating the groundwater model. This guideconcerns only the development, testing, and documentation ofgeneric simulation computer codes, not groundwater m

33、odelapplications.3.1.5 groundwater modeling, nthe process of developinggroundwater models.3.1.6 groundwater modeling code, nthe nonparametrizedcomputer code used in groundwater modeling to represent anonunique, simplified mathematical description of the physicalframework, geometry, active processes,

34、 and boundary condi-tions present in a reference subsurface hydrologic system.3.1.6.1 DiscussionThe term “nonparameterized computercode” refers to a generalized computer program in whichvalues of parameters can be specified by the user.3.1.7 quality assurance (QA), nin the development of agroundwate

35、r modeling code, the procedural and operationalframework put in place by the organization managing the codedevelopment project, to ensure technically and scientificallyadequate execution of all project tasks, and to ensure that theresulting software product is functional and reliable.3.2 For definit

36、ions of other terms used in this guide, seeTerminology D653.2For 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.3

37、The last approved version of this historical standard is referenced onwww.astm.org.4The boldface numbers in parentheses refer to a list of references at the end ofthis standard.D6025 96 (2008)24. Significance and Use4.1 Groundwater modeling has become an important meth-odology in support of the plan

38、ning and decision-makingprocesses involved in groundwater management. Groundwatermodels provide an analytical framework for obtaining anunderstanding of the mechanisms and controls of groundwatersystems and the processes that influence their quality, espe-cially those caused by human intervention in

39、 such systems.Increasingly, models are an integral part of water resourcesassessment, protection, and restoration studies and provideessential and cost-effective support for planning and screeningof alternative policies, regulations, and engineering designsaffecting groundwater. It is therefore impo

40、rtant that beforegroundwater modeling codes are used as planning anddecision-making tools, their credentials are established andtheir suitability determined through systematic evaluation oftheir correctness, performance characteristics, and applicabil-ity. This becomes even more important because of

41、 the increas-ing complexity of the hydrologic systems for which newmodeling codes are being developed.4.2 Quality assurance in groundwater modeling provides themechanisms and framework to ensure that the analytic toolsused in preparing decisions are based on the best availabletechniques and methods.

42、 A well-executed quality assuranceprogram in groundwater modeling provides the informationnecessary to evaluate the reliability of the performed analysisand the level to which the resulting advice may be incorporatedin decision-making regarding the management of groundwaterresources.4.3 This guide i

43、s intended to encourage consistency andcompleteness in the development and evaluation of existingand new groundwater modeling codes by describing appropri-ate code development and quality assurance procedures andtechniques.4.4 In the past, some groundwater modeling codes havebeen developed that have

44、 turned out to be quite useful withouthaving been subject to all of the procedures described in thisguide. Nonetheless, the procedures described in this guide willgive greater assurances that a code does what its developersintended it to do and that a rational basis is available to judgecode adequac

45、y and limitations.5. Code Development Process5.1 In groundwater modeling, code development consists ofthe following:5.1.1 Definition of design criteria and determining appli-cable software standards and practices,5.1.2 Development of algorithms and program structure,5.1.3 Computer programming,5.1.4

46、Preparation of documentation,5.1.5 Code testing, and5.1.6 Independent review of scientific principles, math-ematical framework, software, and documentation.5.2 Code design criteria should address the following:5.2.1 The physical system to be modeled in terms ofgeometry, physical processes and proper

47、ties, and stresses,5.2.2 Assumptions made in deriving the mathematicalframework,5.2.3 Dimensionality, and spatial and temporaldiscretization,5.2.4 Type and form of computed entities,5.2.5 Type and form of code operation control,5.2.6 Code structure, and programming language,5.2.7 Input/output struct

48、ure and applicable data exchangeformats,5.2.8 User interface,5.2.9 Computer platforms for implementation, and5.2.10 Type, contents, structure, and level of detail ofdocumentation.5.3 The development of a specific groundwater modelingcode may be part of a research or development project, basedon an e

49、xisting mathematical model, or derived from an existingset of modeling codes.5.3.1 Code development in groundwater modeling is oftenpart of research aimed at acquiring new, quantitative knowl-edge about nature through observation, hypothesizing, andverifying deduced relationships, leading to the establishment ofa credible theoretical framework for the observed phenomena.The resulting research model represents a fundamental under-standing of the studied groundwater system.5.3.2 The object for model research in groundwater is asubset of the hydrologic sy