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Chinquapin Water System Expansion

Yosemite National Park » Chinquapin Water System Expansion » Document List

The existing Chinquapin water system currently uses one well as a water source to provide water service to the Chinquapin Restroom, the Chinquapin Residence, and the Nature Bridge Campus and Henness Ridge. The existing well has seen a substantial decrease in productivity; the initial capacity test in 2006 indicated the well-produced water at a rate of 27-29 gallons per minute while the most recent capacity test performed in July of 2017 indicated that the well production has decreased to about 4.5 gallons per minute. This current rate is insufficient for the system's water demand needs. This project will seek to find another well water source in the general vicinity of the water system and will make improvements to connect to the existing system.

This scope of this project includes drilling two 8.25" diameter hard rock wells 1,300 deep at each of two well locations. An air-lift flow test followed by a 10-day capacity test will be performed for each well. If it becomes apparent that the first well has enough flow capacity to meet system demands the subsequent well drillings will be canceled. Access to each location shall be made possible by the contractor via tree falling, brushing, and grading.

The determination of the well location will be based upon the well capacity results. Improvements to the selected location will include new well casing, well seal, well level transducer, well pad, well cover, water piping, secondary power lines, 4-20mA signal wiring, and an 8'x10' treatment building. The treatment building will house a chart recorder (charting date, flow, and well depth), flow meter, a sodium hypochlorite crock, backup chemical containment, chemical feed pump, and a programmable logical controller with human interface display. A gravel access road to the treatment building and well shall be designed to allow passage and turnaround of a 4x4 vehicle.

This compliance covers all four well locations with the intent to implement improvements on only one well location of which its selection will be based upon the flow capacity results from the drilled wells.