1、Designation: D 5718 95 (Reapproved 2006)Standard Guide forDocumenting a Ground-Water Flow Model Application1This standard is issued under the fixed designation D 5718; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of las
2、t revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This guide covers suggested components to be includedin documenting and archival of numerical ground-water flowmodel app
3、lications. Model documentation includes a writtenand graphical presentation of model assumptions and objec-tives, the conceptual model, code description, model construc-tion, model calibration, predictive simulations, and conclu-sions. Model archival refers to a file or set of files (in bothwritten
4、and digital format) that contains logs of significantmodel simulations (that is, calibration, sensitivity and predic-tion simulations), supplemental calculations, model documen-tation, a copy of the model source code(s) or executable file(s)used, or both, and input and output data sets for significa
5、ntmodel simulations.1.2 This guide presents the major steps in preparing thedocumentation and archival for a ground-water flow modelapplication. Additional information on ground-water modeldocumentation can be found in EPA-500-B-92-006.21.3 This guide is specifically written for saturated, isother-m
6、al, ground-water flow model applications. The elementspresented for documentation and archival are relevant andapplicable to a wide range of modeled processes (in and out ofthe realm of ground-water flow) and can be tailored for thoseapplications.1.4 This guide is not intended to be all inclusive. E
7、achmodel application is unique and may require supplementarydocumentation and archival.1.5 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
8、and determine the applica-bility of regulatory limitations prior to use.1.6 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 pro
9、fessionaljudgment. 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
10、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:3D 653 Terminology Relating to Soil, Rock, and ContainedFluidsD 5447 Guide for Application of a Gro
11、und-Water FlowModel to a Site-Specific ProblemD 5490 Guide for Comparing Ground-Water Flow ModelSimulations to Site-Specific InformationD 5609 Guide for Defining Boundary Conditions inGround-Water Flow ModelingD 5610 Guide for Defining Initial Conditions in Ground-Water Flow ModelingD 5611 Guide for
12、 Conducting a Sensitivity Analysis for aGround-Water Flow Model ApplicationE 978 Practice for Evaluating Mathematical Models for theEnvironmental Fate of Chemicals43. Terminology3.1 Definitions:3.1.1 application verificationusing a set of parametervalues and boundary conditions from a calibrated mod
13、el 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 to analytical solutions, and comparison1This guide is under the ju
14、risdiction ofASTM Committee D18 on Soil and Rockand is the direct responsibility of Subcommittee D18.21 on Ground Water andVadose Zone Investigations.Current edition approved July 1, 2006. Published August 2006. Originallyapproved in 1995. Last previous edition approved in 2000 as D 5718 95 (2000).2
15、Ground-Water Modeling Compendium, USEPA, Office of Solid Waste andEmergency Response, EPA-500-B-92-006, NTIS No. PB93207504. Available fromthe Superintendent of Documents, U.S. Government Printing Office, Washington,DC, 20402.3For referenced ASTM standards, visit the ASTM website, www.astm.org, orco
16、ntact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.4Withdrawn.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.with othe
17、r similar codes to demonstrate that the code representsits mathematical foundation.3.1.2 boundary conditiona mathematical expression of astate of the physical system which constrains the equations ofthe mathematical model.3.1.3 calibration (model application)the process of refin-ing the model repres
18、entation of the hydrogeologic framework,hydraulic properties, and boundary conditions to achieve adesired degree of correspondence between the model simula-tion and observations of the ground-water flow system.3.1.4 calibration targetsmeasured, observed calculated orestimated hydraulic head or groun
19、d-water flow rates which themodel must reproduce, at least approximately, to be consideredcalibrated.3.1.5 conceptual modelan interpretation or working de-scription of the characteristics and dynamics of the physicalsystem.3.1.6 computer code (computer program)the assembly ofnumerical techniques, bo
20、okkeeping, and control language thatrepresents the model from acceptance of input data andinstructions to delivery of output.3.1.7 ground-water flow modelapplication of a math-ematical model to represent a site-specific ground-water flowsystem.3.1.8 mathematical model(a) mathematical equations ex-pr
21、essing the physical system and including simplifying as-sumptions; (b) the representation of a physical system bymathematical expressions from which the behavior of thesystem can be deduced with known accuracy.3.1.9 simulation loga log used to document (in terms ofinput data, code used, simulation p
22、urpose and results) ofindividual model simulations. (See Appendix X1.)3.2 For definitions of other terms used in this guide, seeTerminology D 653.4. Significance and Use4.1 Ground-water flow models are tools frequently appliedfor the analysis of hydrogeologic systems. Due to the signifi-cance of man
23、y decisions based upon modeling results, qualityassurance measures need to be applied to model applications.Complete model documentation is a mechanism to ensure thequality of the effort.4.2 Several federal and state agencies have developed poli-cies regarding model documentation. This guide provide
24、sconsistency amongst current policies, and should be used as aframework for model documentation.5. Model Documentation5.1 Model documentation includes written and graphicalpresentations of model assumptions and objectives, the con-ceptual model, code description, model construction, modelcalibration
25、, predictive simulations, and conclusions.5.2 IntroductionPresent the modeling objectives, thefunction the model will serve, and a brief general setting of themodel area. Identify the individuals involved with the model-ing effort and their roles.5.2.1 Modeling ObjectivesClearly state the modeling o
26、b-jectives, the purpose and goals of the study, and the applica-bility of the model as part of the study. Discuss what types ofpredictions are to be made with the model.5.2.2 Model FunctionDescribe how the model was usedto satisfy the purpose and goals of the study.5.2.3 General SettingInclude a gen
27、eral setting of relevantinformation on the regional characteristics of topography,geology, hydrology, and land use. Present a regional map withthe study area defined.5.3 Conceptual ModelPresent the conceptual model as asite-specific interpretation (based on collected data) of thecharacteristics and
28、dynamics of the physical system beingstudied. Include discussion on the aquifer system (both geo-logic and hydrologic aspects), hydrologic boundaries, hydrau-lic properties, sources and sinks, and a water budget. The levelof detail in this interpretation should be consistent with theavailable data.
29、Present and discuss data set origins, strengths,deficiencies and their effects on the conceptual model.5.3.1 Aquifer SystemPresent an interpretation of the geo-logic and hydrologic characteristics of the aquifer system.Where appropriate, present hydrogeologic cross-sections andstructural contour and
30、 potentiometric surface maps to illustratedata and interpretations.5.3.2 Hydrologic BoundariesDiscuss the hydrologicboundaries that exist and their type(s) for the aquifer system.5.3.3 Hydraulic PropertiesPresent known hydraulic prop-erties of the aquifer system, such as hydraulic conductivity,trans
31、missivity, storativity, and porosity. If these parametersvary spatially, present the interpretation in map form.5.3.4 Sources and SinksPresent details on the location (ifa point source or sink), and the relative magnitude of thesource(s) or sink(s). If the source or sink is areal in extent,present i
32、nformation as to the variability or distribution.5.3.5 Water BudgetPresent a water budget (either quali-tative or quantitative, depending on the study objectives) thatinterprets how water is entering the aquifer system, how itmoves through the aquifer system, and how it exits the aquifersystem.5.4 C
33、omputer Code DescriptionPresent a description ofthe code used and discuss the selection criteria for the code. Ifa custom or altered code is used, list the vendor name, anyenhancements to the code, and how the code was tested.Present the simplifying assumptions inherent to the code, thelimitations t
34、o the code, and the governing equations that thecode solves.5.4.1 AssumptionsDescribe the assumptions built into thecode, and justify the use of the code based on the studyobjectives and the conceptual model.5.4.2 LimitationsDescribe the limitations to the code, andthe adequacy of its use based on s
35、tudy objectives and theconceptual model interpretation.5.4.3 Solution TechniquesDescribe the solution tech-nique(s) used by the code.5.4.4 Effects on ModelDescribe how the assumptions andlimitations of the code affect model construction, and theirimpact (positive or negative) on model results.D 5718
36、 95 (2006)25.5 Model ConstructionDefine the model domain. Defineinitial conditions, boundary conditions, and hydraulic condi-tions, and the validity of their selection. Discuss any simpli-fying assumptions made to the conceptual model. Discussionshould reference how the conceptual model is compatibl
37、e withthe modeling objectives and function. See Guide D 5610.5.5.1 Model DomainPresent the model domain as anoverlay on a topographic map of appropriate scale. Model gridspacing or element size should be discussed and justified basedon model objectives and the conceptual model. Preprocessingand post
38、processing of model data must be thoroughly docu-mented, including any computer codes used. If the modelconstruction is three-dimensional, describe how the layering isconstructed into the model, and justify the layering based onthe conceptual model.5.5.2 Hydraulic ParametersPresent hydraulic paramet
39、ersassigned throughout the model area. If parameter values varyspatially in the model, present this distribution in map form.Refer to the conceptual model.5.5.3 Sources and SinksPresent sources and sinks, theirrespective stress rates, and how they are incorporated in themodel.5.5.4 Boundary Conditio
40、nsPresent in map form boundaryconditions constructed into the model. Describe the types ofboundaries, and justify their use based on the conceptualmodel. See Guide D 5609.5.5.5 Selection of Calibration Targets and GoalsPresentthe calibration targets and the goals of the calibration andjustify them b
41、ased on the accuracy of the data used to constructthe model and the study objectives.5.5.6 Numerical ParametersPresent selection of any nu-merical parameters used in the solution technique (that is,closure criterion, acceleration, seed factor).5.6 CalibrationPresent and discuss model calibration pro
42、-cedures. Present the results of the calibration simulation in mapform and compare to hydraulic head and flow data. Discusscomparison of calibration simulations to site-specific informa-tion using qualitative and quantitative techniques (see GuideD 5490). Discuss sensitivity analyses and the model v
43、erifica-tion. Discuss and present the simulations overall water budgetand mass balance. Discuss additional insight gained from thecalibration regarding the conceptual model. Justify anychanges made to the conceptual model. Document any pre-processing or post-processing algorithms, and any parameters
44、these algorithms use for processing.5.6.1 Qualitative/Quantitative AnalysisDescribe the typeof analyses used to compare calibration to site-specific data andpresent their results. See Guide D 5490.5.6.2 Sensitivity AnalysisPresent the goals of the sensitiv-ity analysis. Document the procedures used
45、and the results ofthe sensitivity analysis, and their effects on the model. Focusshould be made on those parameters least well defined andmost critical to the model. Justify the range of the sensitivityanalyses based on the accuracy of the data. Provide the resultsof the sensitivity analysis in tabu
46、lar or graphic form. See GuideD 5611.5.6.3 Model Application VerificationModel applicationverification goals should be presented and discussed. Results ofthe verification should be presented in map form. Residualsshould be presented and their significance discussed. Discussand present the simulation
47、s overall water budget and massbalance.5.7 Predictive SimulationsDescribe any predictive simu-lations and how they relate to the study objectives. Detail andjustify the changes made to permit the calibrated model tosimulate these predictions. Present results of any predictivesimulations in graphical
48、 form.5.8 Summary and ConclusionsSummarize the modelingeffort and draw conclusions related to the study objectives.Discuss uncertainties inherent to the model and their effects onconclusions derived from the model.5.9 ReferencesProvide references for data, computercodes, and modeling procedures used
49、 as part of the modelingeffort.6. Model Archive6.1 Maintain a model archive consisting of sufficient infor-mation generated during the modeling effort that a post-modeling audit could be adequately performed by a third partyand such that future reuse of the model is possible. Compo-nents of the archive include the copies of the original data usedto construct the model, simulation logs, a copy of computercodes used in the effort, a copy of the report documentation,and copies of model input and output (hard copy or digitalformat, or both, as ap
