Significance and Use

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.

A properly designed and installed groundwater monitoring well provides essential information on one or more of the following subjects:

Formation geologic and hydraulic properties;

Potentiometric surface of a particular hydrologic unit(s);

Water quality with respect to various indicator parameters; and

Water chemistry with respect to a contaminant release.

1. Scope

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 (i.e., 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 (i.e., silty fine sands with some clay). Formations finer than this (i.e., silts, clays, silty clays, clayey silts) should not be monitored using conventional monitoring wells, as representative groundwater samples, free of artifactual turbidity, cannot be assured using currently available technology. Alternative monitoring technologies (not described in this practice) should be used in these 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, in combination with proper well development ( D5521 ), proper groundwater sampling procedures (D4448), and proper well maintenance and rehabilitation ( D5978 ), 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 (up to 50 % passing a #200 sieve), it is generally necessary to use low-flow purging and sampling techniques ( D6771 ) in combination with proper well design to collect turbidity-free samples.

1.4 This practice applies primarily to well design and installation methods used in drilled boreholes. Other Standards, including Guide D6724 and Practice D6725 , cover installation of monitoring wells using direct-push methods.

1.5 The values stated in inch-pound units are to be regarded as standard, except as noted below. The values given in parentheses are mathematical conversions to SI units, which are provided for information only and are not considered standard.

1.5.1 The gravitational system of inch-pound units is used when dealing with inch-pound units. In this system, the pound (lbf) represents a unit of force (weight), while the unit for mass is slugs.

1.6 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 and health practices and determine the applicability of regulatory limitations prior to use.

1.7 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.

2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.

ASTM Standards

C150 Specification for Portland Cement

C294 Descriptive Nomenclature for Constituents of Concrete Aggregates

D421 Practice for Dry Preparation of Soil Samples for Particle-Size Analysis and Determination of Soil Constants

D422 Test Method for Particle-Size Analysis of Soils

D653 Terminology Relating to Soil, Rock, and Contained Fluids

D1452 Practice for Soil Exploration and Sampling by Auger Borings

D1586 Test Method for Penetration Test (SPT) and Split-Barrel Sampling of Soils

D1587 Practice for Thin-Walled Tube Sampling of Soils for Geotechnical Purposes

D2113 Practice for Rock Core Drilling and Sampling of Rock for Site Investigation

D2217 Practice for Wet Preparation of Soil Samples for Particle-Size Analysis and Determination of Soil Constants

D2487 Practice for Classification of Soils for Engineering Purposes (Unified Soil Classification System)

D2488 Practice for Description and Identification of Soils (Visual-Manual Procedure)

D3282 Practice for Classification of Soils and Soil-Aggregate Mixtures for Highway Construction Purposes

D3441 Test Method for Mechanical Cone Penetration Tests of Soil

D3550 Practice for Thick Wall, Ring-Lined, Split Barrel, Drive Sampling of Soils

D4220 Practices for Preserving and Transporting Soil Samples

D4700 Guide for Soil Sampling from the Vadose Zone

D4750 Test Method for Determining Subsurface Liquid Levels in a Borehole or Monitoring Well (Observation Well)

D5079 Practices for Preserving and Transporting Rock Core Samples

D5088 Practice for Decontamination of Field Equipment Used at Waste Sites

D5254 Practice for Minimum Set of Data Elements to Identify a Ground-Water Site

D5299 Guide for Decommissioning of Groundwater Wells, Vadose Zone Monitoring Devices, Boreholes, and Other Devices for Environmental Activities

D5434 Guide for Field Logging of Subsurface Explorations of Soil and Rock

D5518 Guide for Acquisition of File Aerial Photography and Imagery for Establishing Historic Site-Use and Surficial Conditions

D5521 Guide for Development of Ground-Water Monitoring Wells in Granular Aquifers

D5608 Practices for Decontamination of Field Equipment Used at Low Level Radioactive Waste Sites

D5730 Guide for Site Characterization for Environmental Purposes With Emphasis on Soil, Rock, the Vadose Zone and Ground Water

D5753 Guide for Planning and Conducting Borehole Geophysical Logging

D5777 Guide for Using the Seismic Refraction Method for Subsurface Investigation

D5781 Guide for Use of Dual-Wall Reverse-Circulation Drilling for Geoenvironmental Exploration and the Installation of Subsurface Water-Quality Monitoring Devices

D5782 Guide for Use of Direct Air-Rotary Drilling for Geoenvironmental Exploration and the Installation of Subsurface Water-Quality Monitoring Devices

D5783 Guide for Use of Direct Rotary Drilling with Water-Based Drilling Fluid for Geoenvironmental Exploration and the Installation of Subsurface Water-Quality Monitoring Devices

D5784 Guide for Use of Hollow-Stem Augers for Geoenvironmental Exploration and the Installation of Subsurface Water-Quality Monitoring Devices

D5787 Practice for Monitoring Well Protection

D5872 Guide for Use of Casing Advancement Drilling Methods for Geoenvironmental Exploration and Installation of Subsurface Water-Quality Monitoring Devices

D5875 Guide for Use of Cable-Tool Drilling and Sampling Methods for Geoenvironmental Exploration and Installation of Subsurface Water-Quality Monitoring Devices

D5876 Guide for Use of Direct Rotary Wireline Casing Advancement Drilling Methods for Geoenvironmental Exploration and Installation of Subsurface Water-Quality Monitoring Devices

D5978 Guide for Maintenance and Rehabilitation of Ground-Water Monitoring Wells

D5979 Guide for Conceptualization and Characterization of Groundwater Systems

D6001 Guide for Direct-Push Ground Water Sampling for Environmental Site Characterization

D6067 Practice for Using the Electronic Piezocone Penetrometer Tests for Environmental Site Characterization

D6167 Guide for Conducting Borehole Geophysical Logging: Mechanical Caliper

D6169 Guide for Selection of Soil and Rock Sampling Devices Used With Drill Rigs for Environmental Investigations

D6235 Practice for Expedited Site Characterization of Vadose Zone and Groundwater Contamination at Hazardous Waste Contaminated Sites

D6274 Guide for Conducting Borehole Geophysical Logging - Gamma

D6282 Guide for Direct Push Soil Sampling for Environmental Site Characterizations

D6286 Guide for Selection of Drilling Methods for Environmental Site Characterization

D6429 Guide for Selecting Surface Geophysical Methods

D6430 Guide for Using the Gravity Method for Subsurface Investigation

D6431 Guide for Using the Direct Current Resistivity Method for Subsurface Investigation

D6432 Guide for Using the Surface Ground Penetrating Radar Method for Subsurface Investigation

D6519 Practice for Sampling of Soil Using the Hydraulically Operated Stationary Piston Sampler

D6639 Guide for Using the Frequency Domain Electromagnetic Method for Subsurface Investigations

D6640 Practice for Collection and Handling of Soils Obtained in Core Barrel Samplers for Environmental Investigations

D6724 Guide for Installation of Direct Push Groundwater Monitoring Wells

D6725 Practice for Direct Push Installation of Prepacked Screen Monitoring Wells in Unconsolidated Aquifers

D6771 Practice for Low-Flow Purging and Sampling for Wells and Devices Used for Ground-Water Quality Investigations

F480 Specification for Thermoplastic Well Casing Pipe and Couplings Made in Standard Dimension Ratios (SDR), SCH 40 and SCH 80

Keywords

aquifer; borehole drilling; geophysical exploration; groundwater; monitoring well; site investigation; Aquifers; Borehole drilling; Design--ground-water systems; Field testing--ground water/aquifers; Geophysical investigations/geophysics; Ground-water monitoring/sampling; Hydrogeologic models/investigations; Installation--ground water/subsurface devices/applications; Rock materials/properties/analysis; Site identification/investigation/selection;

ICS Code

ICS Number Code 13.060.10 (Water of natural resources)

DOI: 10.1520/D5092-04R10E01

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ASTM D5092