Tuesday, May 28, 2013

Construction Update for Water Awareness Month!

May is Water Awareness Month! So we're taking the opportunity to explain how we’re improving the way “raw water” from our Peninsula watershed flows through the Crystal Springs Reservoir System to the Harry Tracy Water Treatment Plant (HTWTP), where it is treated before being sent to customers’ taps.

Old outlet structures, such as the one on the left,
are being modified and cut below water level.

Water in the reservoirs is called “raw water,” a generic term used for water resources from nature, e.g. from a local watershed, before purification at a treatment plant.  Local raw water that collects in the Crystal Springs Reservoir, which is comingled with a surplus of Sierra Nevada snowmelt, is pumped through a transmission system into the San Andreas Reservoir. From this reservoir the water is drawn into the HTWTP, which is located nearby.

A crane delivers a steel beam for underwater
construction at Crystal Springs Reservoir

Pipe for new Crystal Springs
Pump Station

San Andreas Rises to Meet Your Needs

Visitors to San Andreas Trail with an astute eye may observe water levels in San Andreas Reservoir rising late this spring as our new Crystal Springs Pump Station is tested during its final stages of construction. Located near Crystal Springs Dam, the new pump station will be able to transport water from Crystal Springs Reservoir to San Andreas Reservoir with 1/3 more capacity and using less power than the old pump station, which was last substantially upgraded in the 1920s. During the testing period this spring, San Andreas Reservoir is expected to rise approximately six feet.

Work at Highway 92 Crossing, Where South to North is Upper to Lower
You’ll also notice construction activities at the south end of Lower Crystal Springs Reservoir just north of the Hwy 92 crossing. This includes seismic improvements to the Upper Crystal Springs Dam Lower Culvert (small bypass tunnel) which conveys water north from the Upper Crystal Springs Reservoir to the Lower Crystal Springs Reservoir. A durable, flexible high density polyethylene (HDPE) liner will be installed within the culvert, which crosses the San Andreas Fault, and a vertical portal will be connected to the culvert upstream of the fault.

Welding at HTWTP

Harry Tracy Water Treatment Plant Upgrades 50% Complete
 Like the Crystal Springs-San Andreas Transmission System, the regional water treatment plant is also undergoing major seismic and capacity upgrades as part of the Water System Improvement Program (WSIP). The Contractor has completed pouring the base for the new 11-million gallon treated water reservoir. Crews continue to work on the addition of new filters, seismic retrofits of critical processing units, and upgrades to electrical and other systems.

We can genuinely say the Hetch Hetchy Water System is more seismically reliable today than it was a year ago. Upon completion of construction, the HTWTP will be able to sustain a capacity of 140 million gallons per day (MGD), for up to 60 days, within 24 hours following a major earthquake on the San Andreas Fault.

Concrete Pour for 11 million gallon Treated Water Reservoir at HTWTP


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