This guide describes a general approach for the use of existing wells in environmental investigations with a primary focus on the subsurface and major factors affecting the surface and subsurface environment.

Existing wells represent a valuable source of information for subsurface environmental investigations. Specific uses of existing wells include:

Well driller logs provide information on subsurface lithology and major water-bearing units in an area. Existing wells can also offer access for downhole geophysical logging for stratigraphic and aquifer interpretations. Examples include natural gamma logs in cased wells and an entire suite of methods in uncased bedrock wells (see Guide D5753). This information can assist in developing the preliminary conceptual model of the site.

Well tests using existing wells may provide information on the hydrologic characteristics of an aquifer.

Monitoring of water levels in existing wells, provided that they are cased in the aquifer of interest, allow development of potentiometric maps and interpretations of groundwater flow directions.

Existing wells are the primary means by which regional drinking water quality is evaluated and monitored.

Existing wells may assist in the mapping of contaminant plumes, and in ongoing monitoring of groundwater quality changes at the site-specific level.

Data from existing wells should only be used when characteristics of the well have been sufficiently documented to determine that they satisfy criteria for the purpose for which the data are to be used.

1. Scope

1.1 This guide covers the use of existing wells for environmental site characterization and monitoring. It covers the following major topics: criteria for determining the suitability of existing wells for hydrogeologic characterization and groundwater quality monitoring, types of data required to document the suitability of an existing well, and the relative advantages and disadvantages of existing large- and small-capacity wells.

1.2 This guide should be used in conjunction with Guide D5730, that provides a general approach for environmental site investigations.

1.3 This guide does not specifically address design and construction of new monitoring or supply wells. Refer to Practices D5092 and D5787.

1.4 This guide does not specifically address groundwater sampling procedures. Refer to Guide D5903.

1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

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 guide offers an organized collection of information or a series of options and does not recommend a specific course of action. This guide 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 guide 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 guide 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

D653 Terminology Relating to Soil, Rock, and Contained Fluids

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

D5092 Practice for Design and Installation of Ground Water Monitoring Wells

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

D5408 Guide for Set of Data Elements to Describe a Groundwater Site; Part One--Additional Identification Descriptors

D5409 Guide for Set of Data Elements to Describe a Ground-Water Site; Part Two--Physical Descriptors

D5410 Guide for Set of Data Elements to Describe a Ground-Water Site;Part Three--Usage Descriptors

D5474 Guide for Selection of Data Elements for Groundwater Investigations

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

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

D5787 Practice for Monitoring Well Protection

D5903 Guide for Planning and Preparing for a Groundwater Sampling Event

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

D5979 Guide for Conceptualization and Characterization of Groundwater Systems

Keywords

environmental site characterization; field investigations; groundwater; hydrologic investigations; monitoring wells; sampling; site characterization; site investigations; subsurface investigations: Documents/documentation--water applications; Environmental site assessment (ESA)--water; Ground-water monitoring/sampling; Wells;

ICS Code

ICS Number Code 13.020.10 (Environmental management)

Citing ASTM Standards

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