Three months ago, Santa Clara County\u2019s largest water agency voted to kill a $3.2 billion plan to build a huge new reservoir in the southern part of the county near Pacheco Pass.<\/p>\n
The Pacheco Reservoir would have been the largest new reservoir built in the Bay Area since 1998 when Los Vaqueros Reservoir was constructed in eastern Contra Costa County.<\/p>\n
But soaring cost overruns, a lack of interest among other water agencies to help pay construction costs and share the water, and a decision by the federal Bureau of Reclamation not to allow water from federal projects to be stored in the reservoir, marked the end<\/a>.<\/p>\n Now the Santa Clara Valley Water District is back with new plans<\/a> to boost water storage. This week, the district, a government agency in San Jose that provides water to 2 million South Bay residents, approved a roadmap for the next 25 years that combines new reservoir projects, groundwater storage and recycled water. The price tag: $3.9 billion.<\/p>\n \u201cWhen I meet people in groups, I\u2019ll say \u2018raise your hand if you\u2019ve ever worried that clean, safe water won\u2019t come out when you turn on your tap,’\u201d said Shiloh Ballard, a water district board member. \u201cAlmost no hands go up. Our job is to make sure you never have to worry.\u201d<\/p>\n Unknown to many people, Santa Clara County \u2014 like Los Angeles and most other urban areas in California \u2014 has seen its overall water use drop in recent decades, even as population has grown. Total water use in Santa Clara County has fallen 20% since 2000, while population grew by 25% over the same time.<\/p>\n The reason: The district has spent millions of dollars to pay people to remove lawns and replace them with water-efficient landscaping, and on rebates for low-water appliances. New statewide building codes also have required low-flush toilets, showerheads, and other water-saving plumbing.<\/p>\n \u201cMost water use is outdoors,\u201d said Kirsten Struve, the water district\u2019s assistant officer for water supply. \u201cAs we see fewer lawns and improved technology indoors, water use goes down.\u201d<\/p>\n Even though there has been significant development, she noted, new condominiums and apartments use far less water than older single-family homes, which often have landscaped yards, leaky plumbing and aging appliances.<\/p>\n So why add new storage at all? Fear of extreme droughts, water officials say.<\/p>\n \u201cI\u2019m an optimist,\u201d Ballard said. \u201cBut we are responsible for making sure people have water. We have to plan for extreme scenarios and be paranoid. We have to anticipate the worst.\u201d<\/p>\n Right now, times are good. Northern California has had three wet winters in a row. Levels in reservoirs and many underground aquifers are above average.<\/p>\n But since 2007, as any longtime resident knows, California has suffered through three big droughts \u2014 in 2007-2009, 2012-2016, and 2020-2022, with severe heat waves and wildfires made worse by rising temperatures from climate change.<\/p>\n The Santa Clara Valley Water District\u2019s planners estimate that current countywide water use of about 285,000 acre feet a year will rise 16% to 23% by 2050 as the population grows and new industries like AI data centers use more water. Complicating matters, the Sierra snowpack, a major source of water, is projected to melt earlier as temperatures continue to rise. In a severe 6-year drought, they say, Santa Clara County could be 69,000 acre-feet short. An acre-foot is about 325,851 gallons, or the amount 10 people use in a year.<\/p>\n On Wednesday, the district\u2019s board approved a 428-page document called the \u201cWater Supply Master Plan 2050\u201d<\/a> to try and reduce future shortages.<\/p>\n A key part of the plan is to continue conservation measures, even in wet years, such as the current program of paying homeowners $2 a square foot to voluntarily remove their lawns. The plan also includes five major projects:<\/p>\n 1) Raising the dam at San Luis Reservoir. Eight water agencies and the federal government signed an agreement last November<\/a> to spend $1 billion to raise the dam at one of California\u2019s largest reservoirs, San Luis Reservoir between Gilroy and Los Banos, by 10 feet. That would create 130,000 acre feet of new storage. The Santa Clara Valley Water District could get up to 60,000 acre feet of that. Pros: There is little environmental opposition. Cons: Caltrans would have to move parts of Highway 152, which could cost $400 million or more.<\/p>\n