17 CAR § 11-509 – Plugging or abandonment of wells

(a) General.
1. (1) To restore geologic and hydrogeologic conditions existing prior to a well’s construction, any person who abandons an abandoned well, as defined in 17 CAR § 11-104(1), must use methods and materials that will protect the ground water from surface contamination and prohibit cross-contamination (co-mingling) of aquifers.
2. (2) Clay, cement, or bentonite will be allowed to plug wells with certain restrictions applied when using bentonite.
(b) Dry holes. If no water is encountered and the landowner does not wish to abandon the well in the event that he or she might plan further development of the well at a later date, the contractor shall complete the well according to the rules, including casing, sealing, and capping the well.
(c) File well abandonment form. All wells plugged in the state should be reported by the water well contractor to the Arkansas Natural Resources Commission on a well abandonment form to be approved by the commission within ninety (90) days of abandonment.
(d) Consolidated formations.
1. (1) When information has been obtained about a well completed in a single consolidated aquifer from a water well construction report, geophysical data, or usage of a down-hole camera, the well shall be plugged with cement, clay, or bentonite to a depth of fifty feet (50’) below the bottom of the surface casing, with a minimum depth of one hundred feet (100’) of depth below land surface.
2. (2) The remaining depth of the well may be filled with clean sand or pea gravel.
3. (3) Wells completed in more than one (1) major aquifer must have a minimum fifty-foot clay, cement, or bentonite seal emplaced:
  1. (A) In the borehole within each confining unit between the aquifers; and
  2. (B) Between any aquifer and the surface overburden.
(e) No information. If no information on well construction is available, the well must be filled from bottom to within two feet (2’) of land surface with clay, cement, or bentonite in a manner that will protect the groundwater flow system.
(f) Unconsolidated formations. All wells in unconsolidated formations will be filled with sand or natural material to twelve feet (12’) of ground surface, from twelve feet (12’) to two feet (2’) with bentonite or cement.
(g) Usage of packers. Packers should be emplaced in wells overlying flowing artesian aquifers, or aquifers with more than seventy-five feet (75’) hydrostatic head to curtail flow prior to plugging and prevent intercommunication of aquifers.
(h) Usage of bentonite.
1. (1) Chips. Bentonite chips may only be used to plug a well if the:
  1. (A) Well’s diameter is four inches (4”) or more;
  2. (B) Well’s depth is less than six hundred feet (600’) below land surface; and
  3. (C) Well contains less than five hundred feet (500’) of standing water.
2. (2) Slurries. Bentonite slurries are not allowed for well abandonment in the unsaturated zone (above water level).
3. (3) Prohibited use of bentonite under certain conditions. Bentonite should only be used in accordance with package label recommendations.
(i) Caves. A driller should contact the commission’s staff for specific abandonment procedures if he or she encounters caves while drilling.