1. The bore shall be backfilled using;
(a) grout which complies with Section 2.4 “Grout materials” of Schedule WQL4 Standards and Terms for the construction of bores and water infiltration galleries; or
(b) clean sand, coarse stone, clay; or
(c) drill cuttings; and
sealed at the surface to prevent any contaminants or surface water from entering the bore.

2. The materials used for backfilling or sealing a bore, as specified in Condition 1, shall be placed from the bottom of the bore upwards, using methods to avoid the segregation or the dilution of material.

3. The water infiltration gallery and excavation shall be backfilled with inert material and sealed at the surface, and the ground level restored to the natural level, and pipe work or any part of the structure shall not protrude above the ground surface after decommissioning.

4. Any bore or water infiltration gallery intercepting groundwater shall be sealed:
(a) to prevent the vertical movement of groundwater between aquifers or water bearing layers within an aquifer; and
(b) to permanently confine the groundwater to the aquifer or  water bearing layer within an aquifer, in which it originally occurred.

5. For a water infiltration gallery, or a bore that is more than five metres deep, tThe  following information shall be recorded at the time of decommissioning and forwarded to Environment Canterbury within ten working days of the completion of decommissioning of the bore or water infiltration gallery:
(a) the location of the bore or water infiltration gallery to within an accuracy of at least 10 metres at a scale of 1:50,000 or larger;
(b) the bore or water infiltration gallery number if known;
(c) the diameter and depth of the bore;
(d) size, type and depth of casing and screen, including information on any alteration made to the casing during decommissioning of the bore;
(e) the type and quantity of fill and sealing materials;
(f) the depth at which fill and sealing materials are placed; and
(g) when a bore is or was used to take groundwater, the static water level and flow rate at the time of decommissioning, where practicable.

• Water > Supply