A monitoring well must terminate at least 12 inches above the established ground surface unless the commissioner determines that no location exists for such a well to provide monitoring information equivalent to an at-grade well.
A monitoring well casing may terminate at-grade only on a roadway, sidewalk, driveway, or a parking area. The location of the well identified by unique well number must be marked on a scaled map with angles and directions from surveyed property corners, a permanent benchmark, or the corners of a permanent structure. The map must be submitted to the commissioner with the well record.
An at-grade monitoring well must be constructed as specified in this subpart.
At-grade well casing must terminate no lower than the established ground surface.
The well must be contained in a protective manhole cover or vault. The top of the manhole cover or vault must be no less than two inches above the established ground surface.
The established ground surface must be sloped to divert surface water or spills away from the well and to allow for traffic movement and snow plowing.
The manhole cover or vault must be installed in a concrete pad at least four inches in thickness and four feet square or four feet in diameter and of sufficient load-bearing capacity to support vehicular traffic.
The manhole cover or vault must be labeled with the words "Monitoring Well" cast or stamped in letters at least one centimeter or one-half inch in height.
All materials used to construct the manhole cover or vault must be resistant and impervious to water, petroleum products, and chemicals likely to be present.
The manhole cover or vault must have a watertight, impervious compression O-ring or gasket.
The manhole cover or vault must meet AASHTO Standards H20-44 and M306-04.
The well casing must be secured with a locking cap or cover according to part 4725.2250, subpart 17. The manhole cover or vault must be secured with a lock or tamper-resistant bolts.
The well label must be placed on the well casing, manhole cover, or vault, or the unique well number may be stamped on the vault.
September 2, 2008
Copyright © 2008 by the Revisor of Statutes, State of Minnesota. All rights reserved.