State Water Project (approx. 55%)
	Hetch Hetchy Reservoir (approx. 30%)
	Alameda Creek Watershed (approx. 15%)
	Niles Cone Groundwater Basin
	Desalination

Groundwater percolation ponds in Fremont.

An inflatable dam on Alameda Creek diverts water to percolation ponds.

ACWD has four sources of water supply. About 55% of our water is purchased from the State Water Project. This water is either purified at one of our two water treatment plants or used to recharge local aquifers. Water from Hetch Hetchy Reservoir in Yosemite National Park is purchased from the San Francisco Public Utilities Commission. This water represents approximately 30% of our total supply. Local runoff from the Alameda Creek watershed accounts for about 15% of our total supply and is specific to recharging the aquifers of the Niles Cone Groundwater Basin.

These four water sources together represent one of our greatest strengths, for they allow us considerable flexibility in water resources management, especially in times of drought. At the same time, we do not directly control all of these sources. Eighty-five percent of our supply comes from the State Water Project and the Hetch Hetchy system, and is controlled by decision-makers outside of our local area.

ACWD has consistently worked to anticipate our region's changing water needs and manage our water supply accordingly. In 1987, our Board adopted a Capital Improvement Plan which detailed the District's facilities needs through 2010 and guided construction of a new water treatment plant, blending facility, distribution system transmission mains, and related facilities. These new facilities have enabled us to continue to meet and exceed increasingly more stringent water quality regulations, meet increased water demands, and enhance our water system's reliability.

To address the continued challenge of providing a high quality, reliable water supply for our existing and future customers, an Integrated Resources Plan (IRP) was adopted in 1995. As the name implies, the IRP is an overall approach to planning that integrates all available resources to meet our water supply reliability goals and the anticipated demand increases that are consistent with the General Plans of the cities we serve. The IRP both addresses ways of adding to our supply and charts a course for making the most efficient use of our existing facilities and supplies so we are well prepared for whatever the future may bring.

 

 

State Water Project

The State Water Project supplies about 55% of our total water supply. This water is imported from the Sacramento/San Joaquin Delta and/or Lake Del Valle via the South Bay Aqueduct and is purified at our water treatment plants before being delivered to customers living in central and south Fremont.  End of the month reservoir levels for the reservoirs that supply the State Water Project can be found here.  Look for Oroville, San Luis, and Del Valle reservoirs.  Rain and snow information related to our State Water Project supply can be found here.

 

 

Hetch Hetchy Reservoir

Thirty percent of our total water supply originates in Hetch Hetchy Reservoir in Yosemite National Park. This water is purchased from the San Francisco Public Utilities Commission under an agreement which entitles ACWD to up to 13,400 acre feet of water per year.  End of the month reservoir levels for Hetch Hetchy Reservoir can be found here.  Look for Hetch Hetchy Reservoir.  Rain and snow information related to our Hetch Hetchy supply can be found here.

 

 

Alameda Creek Watershed

The Alameda Creek watershed is an area of roughly 633 square miles, stretching from Mt. Diablo in the north to Mt. Hamilton in the south, and east to Altamont Pass. The area is populated by more than 200,000 people living in five cities - Dublin, parts of Danville and San Ramon, Livermore, Pleasanton - and thousands more living in unincorporated areas.

Average rainfall in the watershed is 20 inches per year. Runoff from much of the southern region is collected in Calaveras and San Antonio Reservoirs, which are part of San Francisco's water system. Runoff from much of the southeast portion is collected in Del Valle Reservoir, some of which is diverted to ACWD via the South Bay Aqueduct. Runoff from the northern region flows to tributaries of Alameda Creek, where it is carried to ACWD facilities and used for groundwater recharge.

Most of the watershed is undeveloped, open range. Another large portion is comprised of public lands and parks. A smaller portion is used as cropland. Only about seven percent of the total acreage is used for residential, commercial, and industrial purposes.

Virtually all of our local water supply (which comprises 15% of our total supply) originates in the Alameda Creek watershed. Rainwater runoff from the watershed and a portion of our State Water Project supply is captured behind three large, inflatable rubber dams which span the width of the Alameda Creek Flood Control Channel. These dams divert water to several hundred acres of ponds (former gravel quarries) where water percolates to recharge the underlying Niles Cone Groundwater Basin.

Protecting the integrity of the watershed is of critical importance to ACWD. The District continuously samples, analyzes, and monitors the quality of water in Alameda Creek at a special monitoring facility located at the mouth of Niles Canyon near Mission Boulevard and at other key locations throughout the watershed. In addition, we work with property owners and other agencies to encourage proper use of watershed lands so that the water quality in the creek is protected and maintained.

 

 

Niles Cone Groundwater Basin

Local runoff from the Alameda Creek watershed accounts for about 15% of our total water supply and is used to recharge the aquifers of the Niles Cone Groundwater Basin. This runoff, together with water released from the South Bay Aqueduct at a location east of the town of Sunol, flows down Alameda Creek and into the Alameda Creek Flood Control Channel. Here, the water is captured behind three large, inflatable rubber dams. These dams divert water to the Quarry Lakes where water percolates to recharge the underlying groundwater basin.

Sixteen wells are used to extract water from the groundwater basin. Together, these wells are capable of producing up to 47.5 million gallons of water per day. This water is blended with Hetch Hetchy water before being delivered to customers.

The continued protection and enhancement of the Niles Cone Groundwater Basin is vital to ACWD's ability to continue to meet the water supply needs of the people it serves. Consequently, the basin has been the object of vigorous conservation activities on the part of the District. These activities have included an extensive monitoring program to determine the location and movement of saltwater that has intruded into a portion of the groundwater basin.

The Aquifer Reclamation Program, begun in 1973, was developed to stop the spread of the salt water that is already in the basin and to reclaim the intermediate and lower aquifers of the basin for future use. This is accomplished by pumping the salt water into surface drainage channels where it then safely flows to the Bay.

Visit our Groundwater Resources section to learn more about ACWD's groundwater management and protection programs.

 

 

 

Desalination

On September 19, 2003, the Alameda County Water District dedicated the first brackish water desalination facility in northern California. The Newark Desalination Facility (Desal Facility) will produce drinkable water by removing salts and other minerals from brackish groundwater.

The District operates a series of wells that remove brackish water from our groundwater basin. This program, called the Aquifer Reclamation Program, was developed to stop the spread of saltwater already in the groundwater basin and to reclaim the aquifers of the basin for future potable use. Brackish water from some of these wells is treated at the Desal Facility rather than being allowed to flow back into San Francisco Bay.

The Desal Facility utilizes state-of-the-art technology to convert brackish water to potable water. Called reverse osmosis, this process forces water under pressure across a semi-permeable membrane. The membrane allows water molecules to pass through but stops dissolved minerals such as salts and iron.

The soft water produced by the Desal Facility is blended with the harder water pumped from other parts of the groundwater basin to maintain a more uniform water hardness throughout the year and throughout ACWD's service area. So in addition to being a new local source of water, the Desal Facility improves both the quality and reliability of our water supply.