Section 178-12-007 - GROUND WATER MONITORING AND RECOVERY WELLSmust be constructed in the following manner.
12-007.01Well Screens: The top of the screen aperture may extend to within 2 feet of the land surface. The gravel pack thickness may be reduced so as to not compromise the surface seal.12-007.02Watertight Well Casing12-007.02A Casing must be composed of nontoxic durable material compatible with water quality encountered.12-007.02B Wells must be cased with watertight casing through required areas of grout. The watertight casing must extend at least 12 inches above ground level except for construction in sidewalks, roadways, driveways, parking lots, other heavily trafficked areas, or wherever else the situation requires flush mounted installation with watertight caps. 12.007.02C Casing must be chemically resistant to all contaminants which are expected to be encountered.12.007.02D Casing must be equipped with a watertight cap or plug in conjunction with both flush mount and above-ground protectors.12-007.03Grouting the Annular Space: A non-slurry bentonite seal with a minimum thickness of 5 feet must be placed on top of the gravel pack immediately above the screen. All wells must be grouted from immediately above the non-slurry bentonite seal/fine sand to the surface in accordance with 178 NAC 12-003.07.12-007.04Above Ground Protection: Non-steel cased wells completed above ground must be enclosed with a steel casing embedded in the concrete pad and covered with an overlapping, vandal-resistant secured metal cap.12-007.05Pad: Ground water monitoring and recovery wells must have a concrete pad extending a minimum of 1 foot past the walls of the original borehole and must be a minimum of 8 inches thick. The concrete must contact the entire circumference of the casing.12-007.06Well Logs: The location of each well must be shown on a site diagram in addition to the driller's log, to be provided in accordance with 178 NAC 12-003.12A.12-007.07 Nested Well Design: Wells constructed for ground water investigations may use a nested design. (See Figure 10)12-007.07A Individual casings must be separated vertically by a minimum of 2 feet of non-slurry bentonite grout between casings of different lengths within the borehole. A 1-foot minimum non-slurry bentonite grout must be placed on top of each gravel pack interval. The annular space must be grouted as per 178 NAC 12.003.06 and 12-003.07 between non-slurry bentonite grout and the next gravel pack interval.12-007.07B Individual casings must be separated horizontally by a 2 inch annular space, including 2 inches between the outermost casing and the borehole wall.12-007.08Temporary Well Installation: A pre-notification document must be submitted to the Department 30 days before constructing a temporary well to be in use longer than 10 days (does not apply to temporary dewatering wells). The notification must indicate what type of surface seal will be provided. Temporary wells must be decommissioned within 90 days of installation and cannot be used as a monitoring, recovery, or test well on a permanent basis unless the construction complies with the provisions of Title 178 NAC 12-003.04B, or the well is granted a Declaratory Order in accordance with 178 NAC 12013 before it is constructed.178 Neb. Admin. Code, ch. 12, § 007