Chapter NR 141

N = porosity of filter pack

D1 = inside diameter of well casing

D2 = outside diameter of well casing

D3 = diameter of borehole

H1 = height of water column

H2 = length of sand used in filter pack and fine sand filter pack seal or the height of the water column in water table observation wells.

NR 141.21 Note Note: There are 7.48 gallons per cubic foot.

H1 = height of water column

H2 = length of filter pack or the height of the water column in water table observation wells.

NR 141.21(2) (2) Wells that can be purged dry. All permanent groundwater monitoring wells that can be purged dry shall be developed in a manner which limits agitation by slowly purging the well dry. Wells which can be purged dry may not be surged and no water may be added to the well.

NR 141.21 History History: Cr. Register, January, 1990, No. 409, eff. 2-1-90; am. (intro.), (1) (a) and (b) and (2), Register, June, 1991, No. 426, eff. 7-1-91.

NR 141.23 NR 141.23 Well and borehole construction documentation.

NR 141.23(1) (1) All permanent groundwater monitoring well construction shall be reported to the department, using forms and instructions provided by the department, within 60 days after the well has been installed. The completed report shall include the following information:

NR 141.23(1)(a) (a) Well location,

NR 141.23(1)(b) (b) Well casing material and installation procedures,

NR 141.23(1)(c) (c) Well screen materials and installation procedures,

NR 141.23(1)(d) (d) Filter pack materials and installation procedures,

NR 141.23(1)(e) (e) Sealing materials and installation procedures,

NR 141.23(1)(f) (f) Drilling methods and fluids used for installation,

NR 141.23(1)(g) (g) Borehole diameter,

NR 141.23(1)(h) (h) Well development procedures,

NR 141.23(1)(i) (i) Sieve analysis, and

NR 141.23(1)(j) (j) Any other information deemed necessary by the department.

NR 141.23(2) (2) All permanent groundwater monitoring wells installed after February 1, 1990 shall be labeled with labels supplied by the department.

NR 141.23(3) (3) All borehole construction data shall be reported to the department using forms and instructions supplied by the department within 60 days after construction. The completed report shall include the following data: the results of any soil tests done and a description of the soil structure, soil color, mottling, moisture content, layering, jointing, lenses, fractures, organic matter and voids and any other information deemed necessary by the department. The constructor shall report any decontamination procedures used between borehole installations.

NR 141.23 History History: Cr. Register, January, 1990, No. 409, eff. 2-1-90; am. (1) (h), renum. (1) (i) to (j), cr. (1) (i), Register, June, 1991, No. 426, eff. 7-1-91.

NR 141.25 NR 141.25 Abandonment requirements. The following requirements apply to the abandonment of all boreholes greater than 10 feet deep or which intersect a water table and all groundwater monitoring wells. The department may require, by order or other appropriate means, that any borehole or monitoring well be abandoned. The department shall consider the following factors in determining whether a borehole or monitoring well should be abandoned: purpose, location, groundwater quality, age and condition of the well or borehole potential for groundwater contamination and well or borehole construction.

NR 141.25(1) (1) Timelines for abandonment.

NR 141.25(1)(a) (a) A borehole shall be abandoned within 3 working days after its use has been discontinued.

NR 141.25(1)(b) (b) Any permanent groundwater monitoring well no longer being used to gather information on geologic or groundwater properties shall be abandoned within 60 days after its use has been discontinued.

NR 141.25(1)(c) (c) Any groundwater monitoring well found by the department to be acting as a conduit for groundwater contamination shall be abandoned within 15 working days after written notification by the department.

NR 141.25(1)(d) (d) Any groundwater monitoring well constructed after February 1, 1990 not meeting the requirements of this chapter shall be abandoned and replaced with a monitoring well meeting the requirements of this chapter or any department approval granted under this chapter within 60 days after installation of the noncomplying well or 15 days after written notification by the department that the well is noncomplying.

NR 141.25(2) (2) Abandonment procedures.

NR 141.25(2)(a) (a) Boreholes. Any borehole intersecting the water table or greater than 10 feet deep, whose use has been discontinued, shall be abandoned according to the requirements of par. (d).

NR 141.25(2)(b) (b) Monitoring wells — impermeable annular space seals. A permanent groundwater monitoring well known to be constructed with an impermeable annular space seal shall be abandoned according to the requirements of par. (d) after the protective cover pipe and ground surface seal have been removed and the well casing cut off at least 30 inches below the ground surface. The well casing may be completely removed during abandonment by pulling the well casing, overdrilling around the casing and then pulling the well casing out of the ground or by drilling out the well casing completely. If the well casing is to be removed, the well shall be sealed as the casing is removed.

NR 141.25(2)(c) (c) Monitoring wells — permeable annular space seals and wells in waste areas. A groundwater monitoring well not known to be constructed with an impermeable annular space seal or located in an existing or planned future waste disposal or treatment area shall be abandoned by removing the protective cover pipe and the ground surface seal and then completely removing the well casing. The well casing shall be pulled out of the ground as the well is filled according to the requirements of par. (d).

NR 141.25(2)(d) (d) Sealing requirements. Boreholes and groundwater monitoring wells shall be abandoned by complete filling with neat cement grout, bentonite-cement grout, sand-cement grout, concrete or bentonite-sand slurry. When a tremie pipe is used to place the sealing material, the procedures of s. NR 141.10 (2) shall be followed. A tremie pipe shall be used to abandon groundwater wells and boreholes greater than 30 feet in depth or with standing water. Groundwater monitoring wells and boreholes greater than 100 feet in depth shall be sealed with a tremie pipe-pumped method. Bentonite may be used as a sealing material without the use of a tremie pipe under the following conditions:

NR 141.25(2)(d)1. 1. Bentonite granules may be used for abandonment of boreholes and groundwater monitoring wells less than 25 feet deep and when there is no standing water above the filter pack seal.

NR 141.25(2)(d)2. 2. Bentonite chips no greater than 3/8 inch in diameter or bentonite pellets may be used for abandonment of boreholes and groundwater monitoring wells less than 50 feet deep and the depth of standing water is less than 30 feet.

NR 141.25(2)(d)3. 3. Bentonite chips no greater than 3/8 inch in diameter or bentonite pellets may be used for abandonment of boreholes and groundwater monitoring wells which are greater than 4 inches in diameter and less than 250 feet deep and the depth of standing water is less than 150 feet.

NR 141.25(3) (3) Sealant settlement. Any settling of the sealant material shall be topped off. Sealing material may be terminated 30 inches below the ground surface in agricultural areas to avoid interference with agricultural activities. A native soil plug shall be placed on top of the settled sealing material in such cases.

NR 141.25(4) (4) Abandonment documentation. All borehole and permanent groundwater monitoring well abandonments shall be reported to the department within 60 days of the abandonment on forms supplied by the department. In addition to the information required on the form, the person performing the abandonment shall report any decontamination procedures used between borehole and well abandonments.

NR 141.25 History History: Cr. Register, January, 1990, No. 409, eff. 2-1-90; am. (2) (b), (2) (d) 1. to 3. and (3), Register, June, 1991, No. 426, eff. 7-1-91.

NR 141.27 NR 141.27 Driven point wells. Driven point wells with galvanized steel drive pipes and contaminant compatible well screens may be used as permanent groundwater monitoring wells if prior department approval is obtained. Written documentation shall be supplied to the department prior to installation indicating:

NR 141.27(1) (1) That the well is to be used only for water table elevation measurements or to monitor for parameters for which the well casing and screen material will not interfere with the analytical results;

NR 141.27(2) (2) That the well will not provide a conduit for contaminants to enter the groundwater; and

NR 141.27(3) (3) That information on subsurface stratigraphy is not needed. In situations where subsurface geologic information is needed, a separate borehole shall be constructed to collect the required data.

NR 141.27 History History: Cr. Register, January, 1990, No. 409, eff. 2-1-90.

NR 141.29 NR 141.29 Temporary groundwater monitoring wells. Temporary groundwater monitoring wells may be installed according to less stringent standards than specified for permanent groundwater monitoring wells. Any temporary monitoring well construction shall be approved by the department prior to its installation. All temporary monitoring wells shall be abandoned in accordance with s. NR 141.25 within 120 days after their installation.

NR 141.29 History History: Cr. Register, January, 1990, No. 409, eff. 2-1-90.

NR 141.31 NR 141.31 Special circumstances and exceptions.

NR 141.31(1) (1) The department may require or approve more restrictive or alternative well material, assembly, installation, development or abandonment if the contaminant concentrations or geologic setting require alternative construction. Prior written approval is required before any alternative materials are used in monitoring well installation.

NR 141.31(2) (2) Exceptions to the requirements of this chapter may be approved by the department prior to installation or abandonment. An exception request shall state the reasons why compliance with the rule requirements is infeasible. The department may conditionally approve an exception by requiring materials or procedures which safeguard against contamination and result in groundwater monitoring well construction which is substantially equivalent to the requirements of this chapter. Failure to comply with the conditions of an exception voids the department’s approval of the exception.

NR 141.31 History History: Cr. Register, January, 1990, No. 409, eff. 2-1-90.