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Mr. Gerald D j uth October 23, 2003 Page 2 Installation Specifications The monitoring well design and installation will follow California Environmental Protection Agency (Cal EPA) guidance (Cal EPA 1995a). The monitoring well will be constructed using 2-inch ID Schedule 40 flush-threaded PVC casing. The length of the screened interval will be 10 feet. Screens will be constructed with 0.020-inch factory machined slots. A threaded PVC bottom cap shall be installed at the bottom of the well. Organic solvents and glues will not be used. Filter sand will be emplaced from the base of the borehole to approximately 2-feet above the top of the screened interval by pouring it through the inside of the hollow-stem augers. The augers will be lifted from the bottom of the interval at the same rate that the filter sand is emplaced by gravity and the top of the sand will be tagged periodically with a sounding line to confirm the fill depth. The sand gradation will be Lonestar #2/12 Monterey or equivalent. A minimum 3-foot thick bentonite seal consisting of 1/4-inch to 3/8-inch sodium bentonite pellets that are free of additives will be emplaced above the filter pack. The granular bentonite will be located above the water table and will be emplaced by slowly pouring the pellets through the hollow-stem augers. After emplacement, sufficient water will be added and the bentonite will be allowed to hydrate. The grout seal will extend from the top of the bentonite seal to 6-12 inches below the surface. The grout will be mixed in the following proportions or as otherwise specified by the SJC/EHD: • Neat Type I Portland Cement: 94 pounds (1 sack) (or API Class A) • Pure Sodium Bentonite Powder: 3 to 5 pounds (approx. 1/10 sack) • Potable Water: 5 gallons Grout will be emplaced from the bottom up using a grout pipe. Grouting will be inspected and approved by the SJC/EHD. The well surface completion will consist of a lockable, stovepipe well box mounted in a concrete monument with dimensions 4-ft by 4-ft by 4-inches thick. Well Development The monitoring well will be developed per Cal EPA guidance (Cal EPA 1995a) by pumping, surging, and bailing until, to the extent possible, sediments in the bottom of the well are removed, the extracted water becomes clear, and all indicator parameters become stable. As development proceeds, the quantity of water will be monitored and water quality parameters (pH, temperature, and electrical conductivity) will be measured at least once per well volume and recorded on a well development form. Well development will be considered complete when: