WORK PLANS - Laserfiche WebLink

Home Browse Search

boring. Blank casing will be installed from the top of the screened sections to ground surface. A threaded cap will be placed at the bottom of the well screen prior to installation. After the casing is installed, a filter pack of No. 2112 Monterey sand will be placed in the well annulus. The filter pack will extend from the bottom of the boreholes to approximately. 2 feet above the top of the screened section. Prior to annular seal emplacement, a surge block will be two repeatedly pushed through the water in the well to ensure that there is no bridging of filter pack material within the well annulus. After the filter pack is set, the remaining annular space will be filled with bentonite chips to a depth of approximately 1 foot. The bentonite chips will be hydrated with water as they are emplaced. A traffic-rated, Emco-Wheaton well box, with a removable lid, will be placed within a concrete encasement to protect the top of the well casing. The lid will be secured to the well box. An .LO expandable Morrison test well plug, with a Master lock, or similar well plug will be used to secure the top of the well casing. Well Development At least 72 hours after well completion, the well will be developed by surging and bailing. A surge block will be used to draw fine-grained material into the well where it will be removed. After a period of surging, water and suspended fines will be removed using a PVC bailer. This process will be repeated until the removed water contains less than 10 NTUs of suspended solids or a baseline level of turbidity is established. Groundwater depths before and after development, well depth, well development times and dates, volumes of water removed, and turbidity levels will be recorded on a well development log. To prevent cross-contamination, the surge block and LM bailer will be washed with non-phosphate soap and double rinsed in de-ionized water prior to each measurement. Monitoring Well Groundwater Gauging Procedures W Prior to purging, each well will be measured for total depth, depth to groundwater, and separate- phase hydrocarbon thickness, if present,using an electronic interface probe. The electronic interface probe sounds an intermittent alarm when in contact with water, and a continuous alarm when in contact with petroleum hydrocarbons. A measuring tape, graduated to hundredths of a foot, will be attached to the electronic interface probe and adjusted for length of the probe. The electronic interface probe will be lowered into the well and stopped when an alarm sounds. The depth to L, groundwater will be determined by recording the length of the extended measuring tape referenced to the top of the well casing, usually a mark on the top of the casing on the northern side of the well. Separate readings for the depth to separate-phase hydrocarbon and groundwater will be recorded, if L necessary. Measurement accuracy is within approximately 0.01 foot. To prevent cross-contamination, the electronic interface probe will be washed with non- LO phosphate soap and double-rinsed in de-ionized water prior to each measurement. Additionally,