Cement Plant to Provide Water for Shadow Cliffs
By Meera Pal, Contra Costa Times, Walnut Creek, Calif.
Sep. 13–Providing a much-needed backup source for replenishing the 80-acre lake at Shadow Cliffs Regional Recreation Area, the East Bay Regional Park District has announced a deal to receive additional water from a local cement plant.
A popular swimming, boating and fishing spot in Pleasanton, the Shadow Cliffs lake was created in an abandoned gravel quarry pit. Water is lost through seepage and evaporation, especially in the summer.
The park district usually siphons groundwater from the nearby Arroyo del Valle to fill up the lake. But that access is limited, as the arroyo also serves the Zone 7 Water Agency and its customers in Pleasanton, Livermore, Dublin and the Dougherty Valley.
Through a recent agreement, CEMEX — one of the largest cement and ready-mix companies in the country — will provide fresh water from its holding ponds to the park district.
"When we quarry, we keep our water on-site and we sometimes have some in reserve," said Syl LaMacchia, manager of the CEMEX Eliot Plant on Stanley Boulevard. "The water remains on site and is recycled on site."
The water is used to wash sand and gravel — the aggregates — and is available for other uses after it undergoes a several-stage settling process. CEMEX tests the water to meet state standards before releasing the water to streams.
"There is nothing that we do except wash sand and gravel with it," LaMacchia said.
In addition to CEMEX’s testing, park district officials will also monitor the water.
According to spokeswoman Shelly Lewis, the park district is currently adding the infrastructure needed to "pipe the water from the holding ponds to the lake."
LaMacchia estimated the distance between the lake and the ponds to be about 2,000 feet. The plant borders the east side of Shadow Cliffs in Alameda County.
Ultimately, this arrangement could save the park district and taxpayers thousands of dollars annually in potential water usage fees, and in construction costs for alternatives such as pumping water from other quarries.
The 266-acre Shadow Cliffs Recreation Area was donated to the park district by Kaiser Industries. A $250,000 matching grant from the U.S. Bureau of Outdoor Recreation was used to develop the park lands, lake and a four-flume waterslide, parking and picnic grounds.
The popular swim area is open on weekends in spring and fall and daily in the summer.
Quarry companies have long added water to the Arroyo del Valle, keeping its flow through Pleasanton going, usually even through the driest summers. In 2000, some of that water was diverted to Shadow Cliffs; that, along a deactivated quarry pump, resulted in the creek drying up through Pleasanton.
In summer 2006, Zone 7′s board adopted a stream management plan. A key component of the plan is the formation of the "chain of lakes."
These lakes — Shadow Cliffs among them — would form a crescent from northeast Pleasanton to southwest Livermore. It is outlined in the Livermore-Amador Valley Quarry Area Reclamation Plan adopted by the Alameda County Board of Supervisors in 1981.
The stored water would be released downstream only after storms pass through the area, allowing arroyos to maintain a more natural state. Also as part of the management plan, 10 projects would remove or modify fish-passage barriers in Arroyo Mocho, Arroyo del Valle and Arroyo de la Laguna waterways.
Meera Pal covers Pleasanton. Reach her at 925-847-2120 or mpal@bayareanewsgroup.com.
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