Minn. R. agency 144, ch. 4725, DEWATERING WELLS, pt. 4725.6150

Current through Register Vol. 49, No. 24, December 9, 2024

Part 4725.6150 - DEWATERING WELL

Subpart 1.Scope.

This part applies to a dewatering well as defined in Minnesota Statutes, section 103I.005, subdivision 4a. A dewatering well must be constructed, repaired, maintained, and sealed in accordance with the general standards in parts 4725.2010 to 4725.3875, and the requirements of this part. A dewatering well must not be used for a purpose other than dewatering. A dewatering well is exempt from the provisions in parts 4725.4050 to 4725.6050.

Subp. 2.General construction requirements.

A discharge from a dewatering system must not connect to a potable water system.

Subp. 3.At-grade dewatering wells.

A dewatering well cased and completed at-grade must conform to part 4725.6850.

Subp. 4.Loss of potable supply.

A licensee who installs a dewatering well that causes the loss of an adequate private potable water supply must provide the private well owner with a temporary supply of potable water during the operation of the dewatering well. The supply must be adequate for drinking, cooking, and other household uses. The commissioner may require the private well to be tested to determine if a health risk exists before the licensee discontinues an alternate water supply. The licensee must assure that the required testing is completed and reported to the commissioner.

Subp. 5.Sealing.

A dewatering well that is not in use must be sealed according to this chapter.

Subp. 6.Exceptions.

A dewatering well in an unconsolidated formation installed for less than 18 months and less than 50 feet in depth may be constructed and sealed according to the conditions and exemptions in items A to E.

A. Casing is not required to meet the standards of parts 4725.2350 to 4725.2650, if the casing is water tight, free of oil or other contaminants, and withstands the forces exerted on it during installation and removal.

B. The upper termination of the casing must be covered with a tamper-resistant overlapping cover on the casing as specified in part 4725.2250, subpart 17. The casing is not required to terminate at least 12 inches above the established ground surface if the casing extends at least 12 inches above the working grade. The working grade is the temporary elevation of the ground surface during a construction project.

C. The gravel pack must not extend more than ten feet above the static water level.

D. The annular space is not required to be grouted to a depth of 50 feet according to part 4725.3050, subpart 3, if the annular space is filled with cuttings taken from the bore hole.

E. At 18 months after construction or sooner, the well must be sealed according to this chapter. A dewatering well installed for 18 months or less, not encountering a confining layer, less than 50 feet in depth, completed in an unconsolidated formation, and that is not flowing, may be sealed according to part 4725.7450, subpart 4.

Subp. 7.Special construction areas.

The commissioner may require additional construction standards in special well and boring construction areas as described in part 4725.3650.

Minn. R. agency 144, ch. 4725, DEWATERING WELLS, pt. 4725.6150

17 SR 2773; 18 SR 1222; 33 SR 211

Statutory Authority: MS s 103I.101; 103I.111; 103I.205; 103I.221; 103I.301; 103I.401; 103I.451; 103I.501; 103I.525; 103I.531; 103I.535; 103I.541; 103I.621; 144.05; 144.12; 144.122; 144.383; 157.04; 157.08; 157.09; 157.13