- (1) The bore hole containing the vibrating wire piezometers shall have a minimum diameter at least four inches larger than the diameter of the instrument.
- (2) When sealing with a grout or slurry, the bore hole shall be grouted from the bottom up via a tremie tube. The tremie tube may be left within the bore hole provided: It meets casing standards, is filled completely with grout and the annular requirements of this section are met.
- (3) Ungrouted tubing, piping, liner, or casings shall not be left in the bore hole upon completion.
- (4) Individual transducers may be sand packed provided that the sand pack is not more than five feet in thickness.
- (5) Sealing between sand packed transducers shall be designed and constructed to prohibit flow between monitored zones. At no time shall a vibrating wire piezometer bore hole connect aquifers.
[Statutory Authority: Chapter 18.104 RCW. WSR 09-01-125 (Order 08-10), § 173-160-457, filed 12/19/08, effective 1/19/09.]