1、Designation: D5718 95 (Reapproved 2012)Standard Guide forDocumenting a Groundwater Flow Model Application1This standard is issued under the fixed designation D5718; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last r
2、evision. 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 suggested components to be includedin documenting and archival of numerical groundwater flowmodel applicat
3、ions. Model documentation includes a writtenand graphical presentation of model assumptions andobjectives, the conceptual model, code description, modelconstruction, model calibration, predictive simulations, andconclusions. Model archival refers to a file or set of files (inboth written and digital
4、 format) that contains logs of significantmodel simulations (that is, calibration, sensitivity and predic-tion simulations), supplemental calculations, modeldocumentation, a copy of the model source code(s) or execut-able file(s) used, or both, and input and output data sets forsignificant model sim
5、ulations.1.2 This guide presents the major steps in preparing thedocumentation and archival for a groundwater flow modelapplication. Additional information on groundwater modeldocumentation can be found in EPA-500-B-92-006.21.3 This guide is specifically written for saturated,isothermal, groundwater
6、 flow model applications. The ele-ments presented for documentation and archival are relevantand applicable to a wide range of modeled processes (in andout of the realm of groundwater flow) and can be tailored forthose applications.1.4 This guide is not intended to be all inclusive. Eachmodel applic
7、ation 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 and determine t
8、he 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 professionaljudgme
9、nt. 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 manyun
10、ique 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:3D653 Terminology Relating to Soil, Rock, and ContainedFluidsD5447 Guide for Application of a Groundwater Flow Mod
11、elto 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 Sensitivi
12、ty Analysis for aGround-Water Flow Model ApplicationE978 Practice for Evaluating Mathematical Models for theEnvironmental Fate of Chemicals (Withdrawn 2002)43. Terminology3.1 Definitions:3.1.1 application verificationusing a set of parametervalues and boundary conditions from a calibrated model toap
13、proximate 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 software1This guide is under the jurisdiction ofASTM Committee D18 on Soil and Rockand is the direct
14、responsibility of Subcommittee D18.21 on Groundwater andVadose Zone Investigations.Current edition approved May 1, 2012. Published December 2012. Originallyapproved in 1995. Last previous edition approved in 2006 as D5718 95 (2006).DOI: 10.1520/D5718-95R12.2Ground-Water Modeling Compendium, USEPA, O
15、ffice 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, orcontact ASTM Customer Service at serviceastm
16、.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.4The 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
17、-2959. United States1testing, comparison to analytical solutions, and comparisonwith other 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 mathemat
18、ical model.3.1.3 calibration (model application)the process of refin-ing the model representation of the hydrogeologic framework,hydraulic properties, and boundary conditions to achieve adesired degree of correspondence between the model simula-tion and observations of the groundwater flow system.3.
19、1.4 calibration targetsmeasured, observed calculated orestimated hydraulic head or groundwater 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 physi
20、calsystem.3.1.6 computer code (computer program)the assembly ofnumerical techniques, bookkeeping, and control language thatrepresents the model from acceptance of input data andinstructions to delivery of output.3.1.7 groundwater flow modelapplication of a mathemati-cal model to represent a site-spe
21、cific groundwater flow system.3.1.8 mathematical model( a) mathematical equationsexpressing the physical system and including simplifyingassumptions; (b) the representation of a physical system bymathematical expressions from which the behavior of thesystem can be deduced with known accuracy.3.1.9 s
22、imulation loga log used to document (in terms ofinput data, code used, simulation purpose and results) ofindividual model simulations. (See Appendix X1.)3.2 For definitions of other terms used in this guide, seeTerminology D653.4. Significance and Use4.1 Groundwater flow models are tools frequently
23、appliedfor the analysis of hydrogeologic systems. Due to the signifi-cance of many 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 ag
24、encies have developed poli-cies regarding model documentation. This guide providesconsistency 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 objectiv
25、es, the con-ceptual model, code description, model construction, modelcalibration, 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
26、-ing effort and their roles.5.2.1 Modeling ObjectivesClearly state the modelingobjectives, the purpose and goals of the study, and theapplicability of the model as part of the study. Discuss whattypes of predictions are to be made with the model.5.2.2 Model FunctionDescribe how the model was usedto
27、satisfy the purpose and goals of the study.5.2.3 General SettingInclude a general 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
28、-specific interpretation (based on collected data) of thecharacteristics and 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 levelo
29、f detail in this interpretation should be consistent with theavailable data. 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.Wher
30、e appropriate, present hydrogeologic cross-sections andstructural contour and 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 hydr
31、aulic prop-erties of the aquifer system, such as hydraulic conductivity,transmissivity, 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 o
32、f thesource(s) or sink(s). If the source or sink is areal in extent,present information as to the variability or distribution.5.3.5 Water BudgetPresent a water budget (either qualita-tive or quantitative, depending on the study objectives) thatinterprets how water is entering the aquifer system, how
33、 itmoves through the aquifer system, and how it exits the aquifersystem.5.4 Computer 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 test
34、ed.Present the simplifying assumptions inherent to the code, thelimitations to 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 Limitatio
35、nsDescribe the limitations to the code, andthe adequacy of its use based on study objectives and theconceptual model interpretation.5.4.3 Solution TechniquesDescribe the solution tech-nique(s) used by the code.D5718 95 (2012)25.4.4 Effects on ModelDescribe how the assumptions andlimitations of the c
36、ode affect model construction, and theirimpact (positive or negative) on model results.5.5 Model ConstructionDefine the model domain. Defineinitial conditions, boundary conditions, and hydraulicconditions, and the validity of their selection. Discuss anysimplifying assumptions made to the conceptual
37、 model. Dis-cussion should reference how the conceptual model is compat-ible with the modeling objectives and function. See GuideD5610.5.5.1 Model DomainPresent the model domain as anoverlay on a topographic map of appropriate scale. Model gridspacing or element size should be discussed and justifie
38、d basedon model objectives and the conceptual model. Preprocessingand postprocessing of model data must be thoroughlydocumented, including any computer codes used. If the modelconstruction is three-dimensional, describe how the layering isconstructed into the model, and justify the layering based on
39、the conceptual model.5.5.2 Hydraulic ParametersPresent hydraulic parametersassigned 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
40、rates, and how they are incorporated in themodel.5.5.4 Boundary ConditionsPresent in map form boundaryconditions constructed into the model. Describe the types ofboundaries, and justify their use based on the conceptualmodel. See Guide D5609.5.5.5 Selection of Calibration Targets and GoalsPresentthe
41、 calibration targets and the goals of the calibration andjustify them based 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
42、, seed factor).5.6 CalibrationPresent and discuss model calibration pro-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 tec
43、hniques (see GuideD5490). Discuss sensitivity analyses and the model verifica-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. Documen
44、t any pre-processing or post-processing algorithms, and any parametersthese 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 D5490.5.6.2 Sensitivity AnalysisPresent
45、the goals of the sensitiv-ity analysis. Document the procedures used 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 accurac
46、y of the data. Provide the resultsof the sensitivity analysis in tabular or graphic form. See GuideD5611.5.6.3 Model Application VerificationModel applicationverification goals should be presented and discussed. Results ofthe verification should be presented in map form. Residualsshould be presented
47、 and their significance discussed. Discussand present the simulations 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 pr
48、edictions. Present results of any predictivesimulations in graphical 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 ReferencesProv
49、ide references for data, computercodes, and modeling procedures used 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
