1.1 本指南介绍了地下水建模中使用的计算机代码分类和描述的系统方法。由于地下流体流动以及生物和化学运输的复杂性，存在许多不同类型的地下水建模代码，每种代码都有特定的能力和局限性。为特定应用程序确定最合适的代码需要彻底分析手头的问题以及所需和可用的资源，并详细描述潜在适用代码的功能。 1.2 通常，地下水建模代码是对地下含水层选定成分之间的因果关系以及这些系统中发生的化学和生物过程的非参数化数学描述。其中许多代码侧重于在完全或部分饱和条件下，或在这些条件的组合下，水、溶解化学物质和生物群的存在和移动。 其他代码处理水和其他流体的联合运动，无论是作为气体还是非水相液体，或两者兼有，以及它们之间可能发生的复杂相转移。一些代码处理地下水（例如，地下水系统）与水文系统的其他成分或与环境的非水成分之间的相互作用。 1.3 分类协议基于对地下水建模代码中存在的主要功能组的分析。在确定代码的功能时，可以识别其他代码功能和特征。代码功能的描述包含理解地下水建模代码的功能和潜在用途所需的详细信息。表格中提供了所选代码类型的功能和功能组的解释和示例。一致使用分类协议中提供的描述和详细的功能分析构成了高效代码选择的基础。 1.4 虽然存在用于模拟许多不同地下水系统的地下水建模代码，但可能会遇到现有代码可用或适用的情况。在这些情况下，建模需求的系统描述可能基于本指南中提出的方法。 1.5 本指南是关于地下水建模代码及其应用的一系列指南之一，例如指南 D5447 , D5490 , D5609 , D5610 , D5611 和 D5718 . 1.6 完全遵守本指南可能不可行。例如，研究进展可能会产生本指南中尚未描述的新型代码。在这种情况下，代码文档应该包含一个部分，其中包含对代码功能、特性和能力的完整描述。 1.7 本指南提供了有组织的信息收集或一系列选项，并不推荐具体的行动方案。本文件不能取代教育或经验，应与专业判断一起使用。 并非本指南的所有方面都适用于所有情况。本ASTM标准不代表或取代必须根据其判断给定专业服务的充分性的谨慎标准，也不应在不考虑项目的许多独特方面的情况下应用本文件。本文件标题中的“标准”一词仅表示该文件已通过ASTM共识程序获得批准。 ====意义和用途====== 4.1 地下水建模是支持地下水管理中涉及的规划和决策过程的重要方法。地下水模型提供了一个分析框架，用于了解地下水系统的机制和控制以及影响其质量的过程，尤其是人为干预此类系统引起的过程。模型越来越多地成为水资源评估、保护和恢复研究的一个组成部分，并提供所需的资源和成本- 有效支持规划和筛选影响地下水的替代政策、法规和工程设计。 3. 4.2 有许多不同的地下水建模代码可用，每个代码都有自己的功能、操作特点和局限性。如果考虑为项目建模，重要的是确定特定代码是否适合该项目，或者是否存在可以执行项目所需模拟的代码。 4.3 在实践中，通常很难从文档中确定特定地下水建模代码的能力、操作特征和局限性，甚至在没有实际运行代码的情况下也不可能，因为代码的文档不完整、组织不善或不正确，需要为其选择代码。 4. 4.4 基于信息分类的代码特征的系统和全面描述为有效选择特定项目的地下水建模代码或确定不存在代码提供了必要的基础。 本指南旨在通过制定代码分类系统和代码描述指南，鼓励对现有地下水建模代码的功能、能力和限制进行正确、一致和完整的描述。

1.1 This guide presents a systematic approach to the classification and description of computer codes used in groundwater modeling. Due to the complex nature of fluid flow and biotic and chemical transport in the subsurface, many different types of groundwater modeling codes exist, each having specific capabilities and limitations. Determining the most appropriate code for a particular application requires a thorough analysis of the problem at hand and the required and available resources, as well as a detailed description of the functionality of potentially applicable codes. 1.2 Typically, groundwater modeling codes are non-parameterized mathematical descriptions of the causal relationships among selected components of the aqueous subsurface and the chemical and biological processes taking place in these systems. Many of these codes focus on the presence and movement of water, dissolved chemical species and biota, either under fully or partially saturated conditions, or a combination of these conditions. Other codes handle the joint movement of water and other fluids, either as a gas or a nonaqueous phase liquid, or both, and the complex phase transfers that might take place between them. Some codes handle interactions between the aqueous subsurface (for example, a groundwater system) and other components of the hydrologic system or with nonaqueous components of the environment. 1.3 The classification protocol is based on an analysis of the major function groups present in groundwater modeling codes. Additional code functions and features may be identified in determining the functionality of a code. A description of a code’s functionality contains the details necessary to understand the capabilities and potential use of a groundwater modeling code. Tables are provided with explanations and examples of functions and function groups for selected types of codes. Consistent use of the descriptions provided in the classification protocol and elaborate functionality analysis form the basis for efficient code selection. 1.4 Although groundwater modeling codes exist for simulation of many different groundwater systems, one may encounter situations where existing code is available or applicable. In those cases, the systematic description of modeling needs may be based on the methodology presented in this guide. 1.5 This guide is one of a series of guides on groundwater modeling codes and their applications, such as Guides D5447 , D5490 , D5609 , D5610 , D5611 , and D5718 . 1.6 Full adherence to this guide may not be feasible. For example, research developments may result in new types of codes not yet described in this guide. In those cases, code documentation should contain a section containing a full description of a code’s functions, features, and capabilities. 1.7 This guide offers an organized collection of information or a series of options and does not recommend a specific course of action. This document cannot replace education or experience and should be used in conjunction with professional judgment. Not all aspects of this guide may be applicable in all circumstances. This ASTM standard is not intended to represent or replace the standard of care by which the adequacy of a given professional service must be judged, nor should this document be applied without consideration of a project's many unique aspects. The word “Standard” in the title of this document means only that the document has been approved through the ASTM consensus process. ====== Significance And Use ====== 4.1 Groundwater modeling is an important methodology in support of the planning and decision-making processes involved in groundwater management. Groundwater models provide an analytical framework for obtaining an understanding of the mechanisms and controls of groundwater systems and the processes that influence their quality, especially those caused by human intervention in such systems. Increasingly, models are an integral part of water resources assessment, protection and restoration studies, and provide needed and cost-effective support for planning and screening of alternative policies, regulations, and engineering designs affecting groundwater. 3 4.2 There are many different groundwater modeling codes available, each with their own capabilities, operational characteristics, and limitations. If modeling is considered for a project, it is important to determine if a particular code is appropriate for that project, or if a code exists that can perform the simulations needed for the project. 4.3 In practice, it is often difficult to determine the capabilities, operational characteristics, and limitations of a particular groundwater modeling code from the documentation, or even impossible without actual running the code for situations relevant to the project for which a code is to be selected due to incompleteness, poor organization, or incorrectness of a code's documentation. 4 4.4 Systematic and comprehensive description of a code's features based on an informative classification provides the necessary basis for efficient selection of a groundwater modeling code for a particular project or for the determination that no code exists. This guide is intended to encourage correctness, consistency, and completeness in the description of the functions, capabilities, and limitations of an existing groundwater modeling code through the formulation of a code classification system and the presentation of code description guidelines.