Laserfiche WebLink
LFR Inc. <br /> space data. If necessary, the well will be backfilled with bentonite pellets until the <br /> desired depth is achieved. <br /> Approximately 15-foot-long screen will be installed at each injection well, and the <br /> annular space between the well screen and the formation will be filled with No. 2/12 <br /> Monterey sand to a depth of approximately 1 foot above the screened interval. <br /> Approximately 2 feet of bentonite pellets will be placed above the sand pack and <br /> hydrated to form a coherent seal. The remaining annular space above the bentonite seal <br /> will be filled with cement grout. A locking well cap will be placed on top of the well <br /> casing, and the well will be completed using a traffic-rated Christy box. The grout <br /> around the new wells will be allowed to cure for a minimum of 24 hours, after which <br /> the new wells will be developed by bailing, swabbing, or pumping. The development <br /> will remove any sediment left in the well during construction and will enhance the <br /> hydraulic communication between the well and surrounding sediments. Observations <br /> concerning the quantity and clarity of water withdrawn will be recorded during this <br /> process. Indicator parameters (pH, temperature, and specific conductance) will be <br /> recorded during well development. Approximately 3 to 10 well casing volumes will be <br /> removed from each well during the development process. This process will continue <br /> until the indicator parameters stabilize. <br /> 4.2.3 Groundwater Monitoring Well Installation <br /> Two clusters of three groundwater monitoring wells will be installed hydraulically <br /> downgradient from the ERD injection area. Each cluster will be comprised of three <br /> wells; each well will be screened in the upper A zone (proposed wells MW-121A and <br /> MW-122A), lower A zone (proposed wells MW-123A and MW-124A), and B zone <br /> (proposed wells MW-214B and MW-215B). The first cluster will be located <br /> approximately 50 feet east of the existing well cluster comprised of wells MW-108A, <br /> MW-205B, and MW-301C. The second well cluster will be located approximately 250 <br /> feet east of the ERD barrier, adjacent to historical location MIP-19. The purpose of the <br /> first cluster is to monitor the placement and immediate effects of the edible oil substrate <br /> placement. The purpose of the second well cluster is to monitor the long-term effects of <br /> the ERD remedy and the natural attenuation of contaminants in the deeper B-zone <br /> sediments. Only the deepest well of each cluster will be continuously logged and cored. <br /> A California-licensed land surveyor will measure the top-of-casing elevations and <br /> location for each new well to the nearest 0.01 foot. The well elevations will be used to <br /> measure groundwater elevations in each well relative to mean sea level to determine the <br /> direction of groundwater flow. <br /> 4.2.4 ERD Mixing and Injection Equipment <br /> ERD mixing and injection equipment will include the following components: <br /> • One or two 500- to 1,200-gallon high-density polyethylene (HDPE) tanks (poly <br /> tank), or similar; <br /> wp-PhV_1PASep07-Final-06750.dw:Ifr Page 23 <br />