Iowa Administrative Code › Agency 567 - Environmental Protection Commission › Title II - Air Quality › Division A › Chapter 39 - Requirements for Properly Plugging Abandoned Wells › Rule 567-39.8 - Abandoned Well Plugging Procedures

Current through Register Vol. 47, No. 3, July 24, 2024
(1)
Freedom from
				  obstructions.
Abandoned wells must be checked before they are plugged
				  in order to ensure there are no obstructions that may interfere with plugging
				  operations. Drop pipes, check valves, pumps, and other obstructions shall be
				  removed if practical.
(2)
Class 1 wells.
These wells may be plugged by pouring filling
				  and sealing materials from the top of the well or by using tremie pipes, except
				  for sand cement grout or concrete placed below the static water level, which
				  must be placed by tremie pipe or dump bailer.
Filling materials of sand, gravel, crushed stone, rock, pea
					 gravel or agricultural lime shall be placed up to 1 foot below the static water
					 level; soils are not permitted below the static water level due to naturally
					 occurring bacteriological, organic and inorganic contaminants. A minimum of 1
					 foot of bentonite pellets, graded bentonite or neat cement shall be placed on
					 top of the filling material up to the static water level as a seal. Sand cement
					 grout or concrete applied with a tremie pipe or dump bailer also may be used on
					 top of the filling material up to the static water level and in standing water
					 above the static water level to act as a seal. Filling material may then be
					 added up to 4 feet below the ground surface.
It is preferable that the filling materials be omitted and
					 that sealing materials be used to fill the entire well up to 4 feet below the
					 ground surface. Sand cement grout or concrete shall be placed with a tremie
					 pipe or dump bailer when used below the static water level.
The casing pipe and any curbing, frost pipe or pump house
					 structure shall be removed to a depth of 4 feet below the ground surface and
					 shall be capped by a minimum of 1 foot of bentonite pellets, graded bentonite,
					 neat cement, sand cement grout or concrete. The cap shall extend 6 or more
					 inches beyond the outside diameter of the top of the remaining well casing and
					 shall terminate 3 feet below the ground surface. The remaining 3 feet (below
					 the ground surface) shall then be backfilled with soil and graded so that
					 surface water is directed away from the abandoned well location.
(3)
Class 2 wells other
				  than bedrock wells.
If the details of well construction are unknown or
				  obstructions that may interfere with well plugging cannot be removed, the well
				  shall be trended full of neat cement or bentonite grout up to 4 feet below the
				  ground surface. If bentonite grout is used from the static water level to the
				  top of the well, it should be capped by neat cement, sand cement grout or
				  concrete terminating 4 feet below the ground surface.
Filling material consisting of sand, gravel, crushed stone,
					 pea gravel or agricultural lime shall be placed in the bottom of the well up to
					 4 feet below the static water level. A minimum of 4 feet of sealing materials
					 consisting of any bentonite products or neat cement shall be added above the
					 filling material up to the original static water level. If bentonite grout or
					 neat cement is used, it shall be placed by tremie pipe. If graded bentonite or
					 bentonite pellets are used, they may be added by pouring in place and agitating
					 to avoid bridging. Sealing materials shall be added above the static water
					 level up to 4 feet below the ground surface. If bentonite grout is used from
					 the static water level to the top of the well, it should be capped by neat
					 cement, sand cement grout or concrete terminating 4 feet below the ground
					 surface.
It is preferable that the filling materials be omitted and
					 that sealing materials be used to fill the entire well up to 4 feet below the
					 ground surface.
Casing pipe and any curbing, frost pit or pump house
					 structure shall be removed to a depth of 4 feet below the ground surface. The
					 remaining 4 feet shall then be backfilled with soil and graded so that surface
					 water is directed away from the abandoned well location.
(4)
Class 2 bedrock wells.
If the details of well construction are unknown or obstructions that may
				  interfere with well plugging cannot be removed, the well shall be trended full
				  of neat cement or bentonite grout up to 4 feet below the ground surface. If
				  bentonite grout is used from the static water level to the top of the well, it
				  should be capped by neat cement, sand cement grout or concrete terminating 4
				  feet below the ground surface.
The casing pipe and any curbing, frost pit or pump house
					 structure shall be removed to a depth of 4 feet below the ground surface. The
					 remaining 4 feet shall then be backfilled with soil and the surface shall then
					 be graded to divert water away from the abandoned well location.
a.
Bedrock wells completed in a
				  single confined aquifer.
Before proceeding to plug the well, a bridge
				  plug or packer shall be placed at or below the bottom of the casing to stop the
				  flow of water where the pressure in the confined aquifer causes the water to
				  flow from the well to the surface. In such cases, filling materials shall be
				  placed in the lower portion of the well before the bridge plug or packer is
				  set.
Filling material consisting of pea gravel, crushed stone,
					 gravel or agricultural lime shall be placed from the bottom of the well up to
					 10 feet below the bottom of the casing or confining layer, whichever is lower.
					 Sealing materials consisting of any bentonite products, sand cement grout or
					 neat cement shall be placed from the top of the filling material to at least 10
					 feet above the bottom of the casing or confining layer or to the static water
					 level, whichever is higher. If bentonite grout, neat cement or sand cement
					 grout is used, it shall be placed by tremie pipe. If graded bentonite or
					 bentonite pellets are used, they shall be added by pouring in place and
					 agitating to avoid bridging. The casing shall then be filled up to 4 feet below
					 the ground surface with sealing materials. If bentonite grout is used from the
					 static water level to the top of the well, it should be capped by neat cement,
					 sand cement grout or concrete terminating 4 feet below the ground
					 surface.
It is preferable that the filling materials be omitted and
					 that approved sealing materials be used to fill the entire well up to 4 feet
					 below the ground surface.
The casing pipe and any curbing, frost pit or pump house
					 structure shall be removed to a depth of 4 feet below the ground surface. The
					 remaining 4 feet shall then be backfilled with soil and graded so that surface
					 water is directed away from the abandoned well location.
b.
Bedrock wells completed in a
				  single unconfined aquifer.
The plugging procedure for these wells is
				  the same as for bedrock wells completed in a single confined aquifer except
				  that a bridge plug or packer is not required to stop the flow of water since
				  this problem will not exist in this type of well.
c.
Bedrock wells completed in
				  multiple aquifers.
For the lowest aquifer, filling material consisting
				  of pea gravel, crushed stone, gravel or agricultural lime shall be placed from
				  the bottom of the well up to 10 feet below the bottom of the casing or
				  confining layer, whichever is lower. Neat cement trended in place shall then be
				  placed as a sealing material on top of the fill and extend upward at least 20
				  feet. Sealing materials shall then be placed in at least the top 10 feet of
				  each subsequent aquifer and extend at least 10 feet into the confining layer or
				  casing above. The same type of filling materials and sealing procedures shall
				  apply for each subsequent aquifer. Filling material may be placed from the top
				  of the uppermost aquifer seal up to the static water level of the well. The
				  casing shall then be filled with approved sealing or filling materials to 4
				  feet below the ground surface. If bentonite grout is used from the static water
				  level to the top of the well, it should be capped by neat cement, sand cement
				  grout, or concrete terminating 4 feet below the ground surface.
It is preferable that the filling materials be omitted and
					 approved sealing materials be used to fill the entire well up to 4 feet below
					 the ground surface. Sand cement grout or concrete shall be applied with a
					 tremie pipe or dump bailer when applied below the static water level.
The casing pipe and any curbing, frost pit or pump house
					 structure shall be removed to a depth of 4 feet below the ground surface. The
					 remaining 4 feet shall then be backfilled with soil and graded so that surface
					 water is directed away from the abandoned well location.