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September 29, 2014 Monitoring Well Abandonment and <br /> Installation Workplan <br /> Table <br /> Construction Information for Percolation Pond Monitoring Wells. <br /> Diameter Depth Screened <br /> Well ID Status (inches) (feet bis) Interval Objective <br /> (feet bls) <br /> KMW-4 Existing 4 25 Unknown Compliance <br /> KMW-6 Existing 4 27.80a Unknown Compliance <br /> KMW-8 Proposed 4 31 15-30 Compliance <br /> M-9 <br /> Proposed 4 31 15-30 Upgradient well <br /> MBRMW-4 Existing 4 31 15-30 Compliance <br /> a:Well depth from top of casing,measured on 4/28/2014. <br /> 2. Drilling Details <br /> 2.1. Drilling Equipment and Techniques <br /> A C-57 licensed well driller will employ an approved mechanical means (i.e.,auger,rotary, <br /> or cable tool methods)to bore the holes and construct the well to a maximum depth of <br /> about 1 foot below the bottom of the designed well screen depth.The borehole diameter <br /> will be selected so there is a minimum 2-inch radial thickness of sealing material between <br /> the well casing and borehole wall.For the prevailing subsurface conditions encountered in <br /> the Lathrop area (i.e.,unconsolidated sediment),a hollow-stem auger has successfully been <br /> used to drill monitoring well boreholes. <br /> 2.2. Decontamination Procedures <br /> On the basis of historic and current land use and existing groundwater monitoring data,no <br /> hazardous constituents are expected at the drilling locations.The following steps therefore <br /> represent the minimum decontamination procedures to be employed. <br /> • All equipment used for constructing the well must be free of contamination and <br /> cleaned to prevent potential cross contamination.Equipment,tools,materials,etc. <br /> will be decontaminated prior to the beginning of the work and prior to the well <br /> installation.For example,all screens and casings used for monitoring wells should <br /> be in a sterile and contaminant-free condition when placed in the ground. <br /> • Some form of steam cleaning or high-pressure water-spraying technique combined <br /> with a low-suds non-phosphate detergent will be employed followed by rinsing with <br /> potable water.The rinseate and drill cuttings will be spread on the ground at the <br /> adjacent land application area.Discharge to stormwater drains or surface water <br /> features is not acceptable. <br /> HydroFocus, Inc. 6 <br />