CHAPTER SIX

MONITORING WELL DESIGN AND CONSTRUCTION

The following sections provide a basic summary of monitoring well design and

construction techniques. Pursuant to  264.97(c)(1), owners and operators must document in

the operating record the design, installation, development, and decommission of any

monitoring wells, piezometers, and other measurement, sampling, and analytical devices. A

comprehensive guide to choosing appropriate drilling techniques is presented by Aller et al.

(1989). Although much of the guidance presented in this Chapter may be applied to the

design and installation of piezometers, this section is geared to the design and construction of

monitoring wells that will be used to meet the requirements of 40 CFR  264.97.

Furthermore, many of the techniques presented in the following sections are described more

completely in other references and generally will not be discussed in detail in this Chapter.

6.1

Monitoring Well Drilling Methods

The method chosen for drilling a monitoring well depends largely on the following

factors described by Aller et al. (1989):

Versatility of the drilling method;

Relative drilling cost;

Sample reliability (ground water, soil, unconsolidated material, or rock

samples);

Availability of drilling equipment;

Accessibility of drilling site;

Relative time required for well installation and development;

Ability of the drilling technology to preserve natural conditions;

Ability to install well of desired diameter and depth; and

Relative ease of well completion and development, including ability to install

well in the given hydrogeologic setting.

In addition to these factors, Aller et al. (1989) have developed matrices to assist in

selecting an appropriate drilling method. These matrices list the most commonly used drilling

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