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Work Plan Addendum to Install Compliance Groundwater Monitoring <br /> Wells Musco Family Olive Company Tracy California <br /> Piezometer PZ-2 will be installed to complete the triangulation necessary to assess the groundwater <br /> gradient and flow direction. If the water bearing zone detected at MW-35R is consistent with the water <br /> bearing zone detected at MW-34,then the additional piezometers are not necessary and will not be <br /> installed. <br /> If determined to be necessary,the Piezometers will be constructed with 2-inch,schedule 80 PVC <br /> material,as specified in the Well Installation Work Plan. Water levels will be recorded at these <br /> piezometers and assessed in conjunction with the water levels monitored at MW-35R to establish a <br /> gradient and flow direction for groundwater within that water bearing zone. <br /> The piezometers will be installed using a hollow stem auger drill rig.The soil borings will be advanced to <br /> a depth of within 25 feet of the screen interval constructed at MW-35R.When that depth is <br /> encountered,soil sampling will be initiated in five foot intervals to the first water bearing zone or a <br /> depth of approximately ten feet deeper than the depth of MW-35R.The soil borings for the piezometers <br /> will be completed at each location(augers will be left in place in one boring while the soil boring for the <br /> other piezometer is advanced),to verify that the water bearing zone detected at MW-35R is present at <br /> each piezometer location. If the water bearing zone is detected at each piezometer location, a 2-inch <br /> piezometer will be constructed with schedule 80 PVC material and a twenty foot long well screen in <br /> accordance with the procedures described in the Well Installation Work Plan. <br /> If groundwater is not initially encountered at a piezometer during drilling,the soil boring will be <br /> advanced to a depth approximately 10 feet deeper than the depth of MW-35R.The soil boring will be <br /> left overnight and the water level will be checked the following day. If a significant quantity of water is <br /> detected within both of the piezometer soil borings the following day,a piezometer will be installed <br /> with a 20 foot screen interval, in accordance with the procedures described in the Well Installation Work <br /> Plan. If water is not encountered in the soil boring the next day,the soil borings will be abandoned by <br /> tremie grouting neat cement through the augers from the bottom of the soil boring to the top. <br /> Well/Piezometer Development <br /> The newly installed monitoring wells/piezometers will be developed to remove sediment from around <br /> the screen and to enhance hydraulic communication with the surrounding water bearing formation.The <br /> grout installed within the annular seal for the monitoring wells will be allowed to cure for a minimum of <br /> 72 hours before initiating well development activities.The wells will be developed using a combination <br /> of surging and pumping techniques.Observations of indicator parameters,including pH,temperature, <br /> specific conductance,quantity,and clarity,will be recorded onto water-quality data sheets after each <br /> well volume is purged. In the event that a well recovers slowly,the well will be purged dry and then <br /> allowed to recover to approximately 80 percent of its static water level before being purged dry again. <br /> The wells will be developed until relatively sediment-free water is produced,or indicator parameters <br /> stabilize in accordance with the following criteria: <br /> Parameter pH Conductivity ORP Turbidity <br /> Stabilization ±0.1 units ±3% ±10 5 NTU or lowest <br /> Criterion mV technically <br /> feasible <br /> Terraphase Engineering Inc. Page 4 of 6 <br />