1.1 本规程描述了一种设计和安装常规（筛选和过滤填充）地下水监测井的方法，适用于从松散含水层（即砂和砾石）到粒度分布为50%通过200号筛网和20%粘土粒径材料（即含一些粘土的粉质细砂）的地层。可以监测比这更细的地层（即粉土、粘土、粉质粘土、粘土质粉土），但该井可能无法产生足够的采样所需的水，并且细滤包和滤网的安装困难且成本高昂。 在精细地层中使用较粗的过滤器/滤网将导致井的过滤器组不稳定，相关的样品浊度升高，这可能会对样品准确性和数据质量目标产生不利影响。这种做法不适用于裂隙或岩溶岩石条件，但可能适用于其他多孔岩层。 1.2 本实践中提出的推荐监测井设计和安装程序基于这样一种假设，即该计划的目标是从现场特征确定的地下目标感兴趣区域获得代表性地下水样本和其他代表性地下水数据。 1.3 这种做法适用于粗粒砂和砾石含水层，并结合适当的井开发( D5521/D5521M )，适当的地下水取样程序( D4448 )以及适当的油井维护和修复( D5978/D5978米 )，将允许采集没有人为浊度的地下水样本，消除采样事件之间的井淤积，并允许从井筛选的区域采集准确的地下水位和水力传导率测试数据。对于精细安装的井- 粒状地层材料，通常需要使用更精细的预填充井筛( 6.3.3.2 )和/或采用使筛网入口流速和井柱的扰动（包括井中沉降固体的悬浮）最小化的采样方法。使用低流量吹扫和取样技术( D6771 )或无源采样设备( D7929 )是使与浊度相关的潜在样品偏差最小化的两种手段。 1.4 本规程主要适用于钻孔中使用的井设计和安装方法。 其他标准，包括指南 D6724/D6724米 和实践 D6725/D6725米 ，采用直接推压法对监测井进行覆盖安装。 1.5 单位-- 以英寸磅单位或国际单位制（括号内）表示的数值应单独视为标准。每个系统中规定的值可能不是完全相等的；因此，每个系统应独立使用。将两个系统的值合并可能导致不符合标准。括号中给出的等效值显示了配合比设计和筛网尺寸。 1.5.1 筛网名称（规范 E11 )使用“替代”系统进行识别，例如#40、#200筛网等，标称开口尺寸以英寸为单位，颗粒尺寸以毫米为单位。参见规范 E11 标准公制筛网尺寸。 1.5.2 井筛槽以英寸表示，术语部分给出了公制等效值，必要时在标准中给出（参见 3.3.6 ). 1.6 所有观测值和计算值应符合实践中制定的有效数字和四舍五入指南 D6026 ，除非被本标准取代。 1.7 本标准并不旨在解决与其使用相关的所有安全问题（如有）。本标准的使用者有责任在使用前制定适当的安全、健康和环境实践，并确定监管限制的适用性。 1.8 此实践提供了一套用于执行一个或多个特定操作的说明。本文件不能取代教育或经验，应与专业判断结合使用。 Nat本规程的所有方面可能适用于所有情况。本ASTM标准并不代表或取代必须判断给定专业服务是否充分的护理标准，也不应在不考虑项目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共识程序批准。 1.9 本国际标准是根据世界贸易组织技术性贸易壁垒委员会发布的《关于制定国际标准、指南和建议的原则的决定》中确立的国际公认的标准化原则制定的。 ====意义和用途====== 4.1 这种设计和安装地下水监测井的做法将促进 1. 高效有效的现场水文地质特征； 2. 耐用可靠的井结构；和 3. 从监测井中采集具有代表性的地下水质量样本、地下水位和水力传导率测试数据。此处确立的实践受政府法规以及特定地点的地质、水文地质、气候、地形和地下地球化学条件的影响。 为了应对这些地质环境挑战，这种做法促进了在监测井设计和安装之前开发概念水文地质模型。 注1: 该实践提供了一种在大多数地层中有效的监测井设计。此做法通常符合其他国家和州关于井施工的指导文件（ANSI/NGWA-01-14( 1. ) 4. 和加利福尼亚州环保局( 2. 然而国家、州或地方设计法规可以控制设计和安装。 4.2 设计和安装得当的地下水监测井可提供以下一个或多个主题的基本信息: 4.2.1 地层地质和水力特性； 4.2.2 特定水文单元的电位面； 4.2.3 与各种指标参数有关的水质；和 4.2.4 与污染物释放有关的水化学。 注2: 本标准产生的结果的质量取决于执行该标准的人员的能力以及所用设备和设施的适用性。 符合实践标准的机构 D3740 通常被认为能够胜任和客观的测试/取样/检查。可靠的结果取决于许多因素；实践 D3740 提供了一种评估其中一些但不是全部因素的方法。 实践 D3740 是为从事土壤和岩石实验室测试和/或检查的机构开发的。因此，它并不完全适用于执行这种做法的机构。然而，该实践的使用者应认识到，实践的框架 D3740 适用于评估执行此做法的机构的质量。目前还没有已知的合格的国家当局来检查执行这种做法的机构。建议使用经认证的水井钻机。有国家和州机构对水井钻探商进行认证。

1.1 This practice describes a methodology for designing and installing conventional (screened and filter-packed) groundwater monitoring wells suitable for formations ranging from unconsolidated aquifers (that is, sands and gravels) to granular materials having grain-size distributions with up to 50 % passing a #200 sieve and as much as 20 % clay-sized material (that is, silty fine sands with some clay). Formations finer than this (that is, silts, clays, silty clays, clayey silts) can be monitored but the well may not yield sufficient water required for sampling, and fine filter pack and screen requirements are difficult and costly to install. Use of coarser filter/screens in fine formations will result in wells with unstable filter packs and associated elevated sample turbidity that may adversely affect sample accuracy and data quality objectives. This practice is not applicable in fractured or karst rock conditions, but may be applicable for other porous rock formations. 1.2 The recommended monitoring well design and installation procedures presented in this practice are based on the assumption that the objectives of the program are to obtain representative groundwater samples and other representative groundwater data from a targeted zone of interest in the subsurface defined by site characterization. 1.3 This practice when used on coarse grained sand and gravel aquifers, in combination with proper well development ( D5521/D5521M ), proper groundwater sampling procedures ( D4448 ), and proper well maintenance and rehabilitation ( D5978/D5978M ), will permit acquisition of groundwater samples free of artifactual turbidity, eliminate siltation of wells between sampling events, and permit acquisition of accurate groundwater levels and hydraulic conductivity test data from the zone screened by the well. For wells installed in fine-grained formation materials, it is generally necessary to use much finer pre-packed well screens ( 6.3.3.2 ) and/or employ sampling methods that minimize screen intake flow velocity, and disturbance of the well column including suspension of settled solids in the well. Using low-flow purging and sampling techniques ( D6771 ) or passive sampling devices ( D7929 ) are two means to minimize the potential sample bias associated with turbidity. 1.4 This practice applies primarily to well design and installation methods used in drilled boreholes. Other standards, including Guide D6724/D6724M and Practice D6725/D6725M , cover installation of monitoring wells using direct-push methods. 1.5 Units— The values stated in either inch-pound units or SI units [presented in brackets] are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard. Equivalent values given in parentheses are shown for mix designs and sieves sizes. 1.5.1 Sieve Designations (Specification E11 ) are identified using the “alternate” system, for example, #40, #200 sieve etc. with nominal opening size in inches and particle sizes in mm. See Specification E11 for standard metric sieve sizes. 1.5.2 Well screen slots are expressed in inches and the metric equivalent is given in the terminology section and when necessary in the standard (see 3.3.6 ). 1.6 All observed and calculated values shall conform to the guidelines for significant digits and rounding established in Practice D6026 , unless superseded by this standard. 1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. 1.8 This practice offers a set of instructions for performing one or more specific operations. This document cannot replace education or experience and should be used in conjunction with professional judgment. Nat all aspects of this practice 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. 1.9 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee. ====== Significance And Use ====== 4.1 This practice for the design and installation of groundwater monitoring wells will promote (1) efficient and effective site hydrogeological characterization; (2) durable and reliable well construction; and (3) acquisition of representative groundwater quality samples, groundwater levels, and hydraulic conductivity testing data from monitoring wells. The practices established herein are affected by governmental regulations and by site-specific geological, hydrogeological, climatological, topographical, and subsurface geochemical conditions. To meet these geoenvironmental challenges, this practice promotes the development of a conceptual hydrogeologic model prior to monitoring well design and installation. Note 1: This practice presents a design for monitoring wells that will be effective in the majority of formations. This practice is in general accordance with other national and state guidance documents on well construction (ANSI/NGWA-01-14 ( 1 ) 4 and California EPA ( 2 )) however; national, state, or local design regulations may control design and installation. 4.2 A properly designed and installed groundwater monitoring well provides essential information on one or more of the following subjects: 4.2.1 Formation geologic and hydraulic properties; 4.2.2 Potentiometric surface of a particular hydrologic unit(s); 4.2.3 Water quality with respect to various indicator parameters; and 4.2.4 Water chemistry with respect to a contaminant release. Note 2: The quality of the result produced by this standard is dependent on the competence of the personnel performing it and the suitability of the equipment and facility used. Agencies that meet the criteria of Practice D3740 are generally considered capable of competent and objective testing/sampling/inspection. Reliable results depend on many factors; Practice D3740 provides a means of evaluating some, but not all, of those factors. Practice D3740 was developed for agencies engaged in the laboratory testing and/or inspection of soils and rock. As such, it is not totally applicable to agencies performing this practice. However, user of this practice should recognize that the framework of Practice D3740 is appropriate for evaluating the quality of an agency performing this practice. Currently there is no known qualifying national authority that inspects agencies that perform this practice. Use of certified water well drillers are recommended. There are national and state agencies that certify water well drillers.