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Monitoring Well Installation Workplan Page 4 of 6 Our Project Number: LES080548 July 10, 2008 The drill rig and all down-hole tools will be cleaned using a high-pressure, hot water wash prior to drilling. The rig will similarly be cleaned between borehole and prior to leaving the site. Soil sampling tools will be cleaned with a non-phosphate detergent (e.g., Liqui-Nox) after each use. 2.2.2 Monitoring Well Installation All materials used during well construction will be new and will be kept in original packaging away from potential sources of contamination, until ready to use. Monitoring wells is anticipated to be installed to a depth of 30 feet below ground surface with filter pack #3 sand being placed from 30 feet to 13 feet below ground surface. The monitoring well casing will rest on this filter pack. All monitoring wells will be constructed of 2-inch diameter, flush-thread PVC well casing with 15 feet of 20-slot well screen and 18 feet of solid surface casing. The base of the monitoring well will include a flush-thread solid end cap. The annulus between the monitoring well screen and borehole wall will be back-filled with approximately 17 feet of #3 sand. The #3 sand will extend two feet above the screen interval. Prior to placement of the transition seal the sand pack will be surged with a surge block to ensure that the sand pack does not contained any bridged material. Once the sand is surged, the sand pack will be measured to ensure that it remains two feet above the well screen. After the sanding is completed, the transition seal will be placed. The transition seal will consist of approximately two (2) feet of non-coated bentonite chip seal. The bentonite will be hydrated prior to filling the remaining annulus with a cement grout. The cement grout will consist of a thoroughly mixed combination of seven (7) gallons of water for each 94 lbs. bag of Portland cement. The grout shall be tremied in placed in order to avoid disturbing the hydrated bentonite seal. The combination of 2-inch diameter well casing and 8-inch nominal diameter well borehole will assure a minimum of a 2-inch annual seal between the well pipe and the well borehole. After placement of the grout column, a 2-foot by 2-foot by 4 inch concrete surface seal will be installed, and will include a 6 inch monument type well head enclosure. The concrete surface seal will be sloped to prevent water build up on the well lid. A reference mark will be placed on top of the well casing. The well head on the well will be secured with a water tight well head cap and a padlock. Four crash posts will be installed to protect the monitoring well. The proposed monitoring well design is presented on the Monitoring Well Construction Detail (see Plate 3). The on-site geologist will create a well completion and boring log for each well. The log will document the as-built well construction features and the subsurface conditions encountered during drilling. A 902 Industrial Way • Lodi, CA 95240 • 209.367.3701 • Fax 209.369.4228 ©2008 Neil 0. Anderson & Associates, Inc