6.5

Surface Completion

The surface completion of monitoring wells is described in detail by Aller et al.

(1989). In general, completing a monitoring well will involve installing the following

components:

Surface seal;

Protective casing, utility vault, or meter box;

Ventilation hole(s);

Drain hole(s);

Cap;

Lock; and

Guard posts.

Monitoring wells are commonly completed at the surface in one of two ways: as

above ground completions or as flush to ground completions. The purpose of both types of

completion are to prevent infiltration of surface runoff into the well annulus and to prevent

accidental damage or vandalism of the well.

A monitoring well surface seal should be installed on top of the grout seal (Section

6.4) and extend vertically up the well annulus between the well casing and the borehole to the

land surface. Where appropriate, the lower end of the surface seal should extend at least one

foot below the frost line to prevent damage from frost heaving. The composition of the

surface seal should be neat cement or concrete. In above ground well completions, the

surface seal should form at least a two foot wide, four inch thick neat cement or concrete

apron at the land surface. The apron should be constructed with a slight slope to drain

surface water radially away from the well casing to prevent leakage down the outer casing

wall.

A locking protective casing should be installed around the well casing to prevent

damage or unauthorized entry. The protective casing should be anchored below the frost line

(where applicable) into the surface seal and extend at least 18 inches above the surface of the

ground. A 1/4 inch vent hole pipe is recommended to allow the escape of any potentially

explosive gases that may accumulate within the well. In addition, a drain hole should be

installed in the protective casing to prevent water from accumulating and, in freezing

climates, freezing around the well casing. The space between the protective casing and the

well casing may be filled with gravel to allow the retrieval of tools and to prevent small

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