OAR 690-240-0540: Direct Push Monitoring Wells and Piezometers

(1) Monitoring wells and piezometers that are installed using direct push technology shall comply with the applicable standards in these rules. (2) Monitoring wells and piezometers that are installed using direct push technology shall also comply with the following standards: (a) Only prepacked screens shall be used; and (b) The outside diameter of the borehole shall be a minimum of two inches greater than the outside diameter of the well casing; and (c) Granular bentonite shall not be used in the casing seal interval below the static water level; and, (d) Monitoring wells and piezometers shall not be constructed through more than one water bearing formation and shall not be greater than 50 feet in depth; and (e) Monitoring wells and piezometers that extend deeper than 30 feet shall be equipped with centering guides to insure proper centering of casing. Guides shall be spaced at minimum ten foot intervals and attached to the casing. (3) Monitoring wells and piezometers larger than two inches in diameter shall not be installed using direct push technology without prior Department approval.