El Portal Well System Rehabilitation

Yosemite National Park » El Portal Well System Rehabilitation » Document List

The El Portal water distribution network obtains water through a system of wells that serve Rancheria Flat, Old El Portal, the Trailer Court, and the El Portal Maintenance Complex. The existing water systems including the associated buildings, and mechanical and electrical systems are worn and obsolete and require a high amount of maintenance consisting of both preventative and reactive measures. The wells range in age from 25 to 40 years old. All well systems are considered at or beyond their service life.

There is a high risk of failure at any of these well system components. A single well failure will place excessive strain on the remaining wells to maintain system demand. Simultaneous well failure of multiple well systems will render the system unable to meet community water demands for domestic consumption and fire flow.

The purpose of this project is to provide the following corrective measures to the existing well system (wells 2, 3, 4, 5, 6, 7):
• Construction of 6' x 6' well pad and security enclosure for Wells #2, 3, 4, 5, 6, and 7. There will be 6" maximum of soil disturbance for subgrade compaction.
• Rehabilitation of Well House 4 and 5 (reroofing, interior renovation, exterior painting).
• Demolition of existing Tank #3 control building and installation of a new control building. New control building will be a 10.5' x 12' precast concrete unit and painted Wosky Brown. This work includes 6" of soil disturbance for subgrade compaction.
• Improve well system equipment including radio survey, SCADA, transmitter, RTU, and Tank 3 level sensor.
• Drill three test wells, in two locations in the El Portal Rancheria area to gauge availability of groundwater to supply an additional well (preliminary fact gathering for a potential future project). A 6' x 6' concrete well pad will be installed for each test well. Soil disturbance will be kept at a maximum depth of 6" for soil compaction.