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Issue link: http://wateronline.epubxp.com/i/628452
the SFPUC will provide up to 5.5 MGD of additional surface water to the Project's partner agencies in lieu of their groundwater pumping. Over time, the reduced pumping will result in the storage of up to 60,500 acre-feet or 20 billion gallons of water. The SFPUC will only pump groundwater that has been previously stored — thus ensuring the sustainability of the project. The Project is currently installing up to 16 new groundwater wells and well stations, including chemical treatment equipment, tanks, pumping systems, and associated pipelines to extract, t re a t , a n d distribute stored g r o u n d w a t e r in dry years. It is designed to help meet water demands during a 7.5-year-long drought (i.e., recovery of 8,050 acre-feet per year), thereby stretching the SFPUC's regional water resources. This dry-year supply will benefit all 2.6 million customers who depend on the SFPUC for all or part of their water supply. Two types of well stations are being built — wells housed inside buildings with separate rooms for the well and chemical treatment and wells housed in outdoor, fenced enclosures without chemical treatment. Wells housed indoors will have vertical turbine deep well pumps and variable frequency drives. Wells housed outdoors have submersible pumps to avoid noise impacts. The water from these wells will be pumped to the indoor well stations or partner facilities for treatment. All of the groundwater will be chlorinated and, depending on the location, water quality, and point of connection, groundwater may also be adjusted for pH, fluoridated, and filtered for manganese. The Project's wells and well pumps are designed to operate in a range of changing groundwater water levels — i.e., to accommodate higher water levels during the initial years of recovery and lower water levels following multiple dr y years. Over a 7.5-year drought recovery period, existing water levels could decline by up to 100 feet, and pumping water levels could decline by 180 feet. The SFPUC's ability to deliver high-quality water every day requires proactive planning and infrastructure investment. This is especially true as California faces some of the driest years on record. This Project will help increase San Francisco's water supply resilience, diversify its water supply portfolio, and reduce dependence on surface water, making the SFPUC's Hetch Hetchy Regional Water System less vulnerable to natural disasters such as droughts and earthquakes. n wateronline.com n Water Innovations GROUNDWATER 25 Greg Bartow is the groundwater program manager for the San Francisco Public Utilities Commission and project manager for the SFPUC's Regional Groundwater Storage and Recovery Project. About The Author The construction team is now on the second phase of work, which includes the well facility development. Each well facility will have various rooms to monitor, test, and pump water if needed. The drill rig was a critical part to the flow and function of this project. At each site, our construction teams drilled between 400 to 900 feet deep to develop new groundwater wells. In wet years, municipal pumping is decreased and groundwater fills the available aquifer storage space. The SFPUC will only pump groundwater that has been previously stored — thus ensuring the sustainability of the project.