News

From the source: Tracing Palo Alto's water supply

City's water travels from Sierras in century-old system to reach people's taps

Downstream of a small canyon dotted with skinny ponderosa pines and incense cedar trees, rushing water cascades over large granite slabs. It flows around large boulders, pouring over round smooth rocks as it makes its way to the nearby Hetch Hetchy Reservoir. The sound is loud enough to drown out an encroaching thunderstorm.

This water, which began as snowmelt, will travel 167 miles over the next three days through a system dating back 92 years. It is this system that provides more than 2.5 million Bay Area residents with the majority of their drinking water.

Water has been a subject on a lot of people's minds lately. They've let their lush green lawns fade to brown, placed buckets in showers and opted to run the dishwasher only when completely full. But how often do people stop to think beyond their water bills and consider the long journey and feat of engineering it takes for water to reach their faucets?

"I think a lot of people probably take it for granted that when they turn on the faucet, water just appears," said Catherine Elvert, communications manager for the City of Palo Alto Utilities (CPAU) department. "A lot goes into getting that water supply and making sure that it's safe."

The journey for Palo Alto's water begins high up in the Sierra Nevadas in Yosemite National Park, where snow settles on mountains and glaciers at altitudes of 13,000 feet. In spring and summer about 12 percent of the watershed's melted snow and rainfall flows into three reservoirs: Hetch Hetchy, Cherry Lake and Lake Eleanor.

The picturesque Tuolumne River, admired for its whitewater rapids and a home for spawning Chinook salmon and steelhead trout, is the main conduit filling the Hetch Hetchy Reservoir. In fact, 60 percent of the river's flow is diverted for agriculture and urban water use in the Central Valley and the Bay Area.

Over the past four years, warm dry winters have caused rainfall and snowpack levels to drop drastically. Readings taken by the California Department of Water Resources on April 1 found that statewide peak snowpack levels were only at about 5 percent of average — a dismal 1.4 inches compared to 28.3 inches, the average since 1941.

One of the Tuolumne River's sources, the glacier at Mount Lyell, has shrunk by 6 to 8 feet in the past two years. According to the nonprofit Tuolumne River Trust, geologists anticipate the glacier could be gone in about five to 10 years if warm-weather patterns persist.

These historically low snowpack levels prompted Governor Jerry Brown to declare a drought state of emergency and issue a statewide mandate that water providers must cut their water consumption by about 25 percent from June 1, 2015, to February 28, 2016 — or face strict fines and penalties.

"The snowpack is really important; in a way, it's an additional reservoir," Peter Drekmeier, policy director of the Tuolumne River Trust, told the Palo Alto Weekly.

---

One of the factors that sets Palo Alto's drinking water apart is its quality. About 85 percent of the tap water, which is purchased and provided by the San Francisco Public Utilities Commission (SFPUC), is from the Hetch Hetchy Reservoir. Unlike water supplied from other reservoirs and the ground, Hetch Hetchy water is so pure that it doesn't need to be filtered.

On a popular trail that stretches around the Hetch Hetchy Reservoir, hikers can pose to take photos and view waterfalls like Wapama Falls, where crystal clear water plummets directly into the reservoir. This unique geology in Yosemite is what keeps the water free from sedimentation.

"It's really one of the best drinking supplies in the world," Drekmeier said.

Back in the late 19th century, engineers also saw the value of this pristine water source from the mountains. But it wasn't until the 1906 earthquake and great fire in San Francisco, which destroyed most of the city's water mains, and subsequent action by Congress that the O'Shaughnessy Dam could be built, creating the 117-billion-gallon Hetch Hetchy Reservoir.

The system can transfer more than 200 hundred million gallons of water per day to 26 different cities and water districts. It is entirely powered by gravity, a fact that allows it to create energy at two hydropower stations downstream: Kirkwood and Moccasin Powerhouse, which supply electricity to San Francisco's municipal buildings and the San Francisco International Airport.

Compare that power generation to the energy it takes to transport all other forms of water across California — nearly 20 percent of statewide energy use.

As the water flows from the Moccasin Powerhouse into the Central Valley, it travels underneath the Don Pedro Reservoir. Driving on State Route 120 to or from Yosemite, motorists can stop at a scenic viewpoint overlooking the man-made lake and stretch their legs. In wetter years, the bright blue water in the lake entices recreational boaters and water-sport enthusiasts.

This year the land is parched. Huge banks of dry land rise above the shallow water, their striations showing the heights the water used to reach. This 665-billion-gallon lake, mainly used for agriculture irrigation in Modesto and Turlock districts, is currently at only 40 percent capacity. Elsewhere in California, Lake Shasta reservoir is at 51 percent and Lake Oroville reservoir, 43 percent.

Compared to the growing number of low-level reservoirs in the state, Hetch Hetchy Reservoir's water level remains fairly stable. In early June it was at 91.8 percent of its capacity.

Steve Ritchie, assistant general manager for water for the SFPUC, said that there are many factors responsible for this comparatively good situation.

Since Yosemite reservoirs are relatively small, they tend to fill up multiple times in good years. The excess water is stored in local reservoirs closer to the Bay Area as well as in the Don Pedro Reservoir, for which the SFPUC has a water-bank agreement. This bank of water can be released in dry summer months when upstream levels are diminished.

But other factors are in play, too. In 2014 the SFPUC asked water districts to voluntarily reduce water use by 10 percent, and with the added pressure of the governor's drought mandates, residents are taking shorter showers and watering landscapes less frequently. So far in 2015, SFPUC's customers have used the least amount of water since 1977.

"Some of the high reservoir level is due to low demand, but mainly it's because we smartly manage our water and have the ability to bank water in advance with our downstream partners," Ritchie stated in an email.

Downstream, one such local source is the Calaveras Reservoir, which is currently part of the $4.6 billion Water System Improvement Program (WSIP) to seismically upgrade the entire system's infrastructure. In a valley in the Fremont hills, huge bulldozers are digging through layers of dirt and rock while crews laying cement are dwarfed by the 200-foot walls of a new earth-fill dam that's under construction. The project will restore the reservoir capacity to 31 billion gallons, providing Palo Alto with most of the 15 percent of its water supply. Today, the water in the reservoir is being held at 24 percent of total capacity due to the construction and the drought, which has dried up the local watershed that feeds into the reservoir.

---

Rising costs in Palo Altans' water bills in part are helping to cover the massive improvement project, which also includes a new tunnel underneath the bay, and upgraded Irvington Tunnel (which runs along two earthquake fault lines) and additional storage. People may grumble about higher bills, but Elvert said the security of a reliable water source is at stake.

"If you compare the cost of municipal tap water — which is incredibly pristine (and) high quality, regulated by the state and federal agencies — and if you compare that cost to bottled water, you're paying less than a tenth of a cent per gallon. It's a pretty good deal," she said.

Part of the cost also involves treating water to eliminate environmental contaminants. Hetch Hetchy water is first treated with UV light to kill any harmful bacteria or microorganisms at the Tesla Water Treatment Facility in Tracy. Then it is disinfected at a small treatment facility in Sunol. Any water that is stored in the Calaveras and San Antonio reservoirs must be treated separately from the direct Hetch Hetchy supply at the Sunol Valley Water Treatment Plant a few miles southwest of Calaveras.

Chris Nelson, water supply and treatment division manager for the plant, recently led a tour explaining how water from Calaveras and the nearby San Antonio Reservoir is treated.

He pointed to the tank with shimmering turquoise water that resembled a community swimming pool and explained that the first step is a process called flocculation, which adds a chemical to the water to force silt and sediment to fall to the bottom of the tank.

Next, the water is filtered and passes through tanks filled with minerals, sand and rocks, like a giant Brita filter, until it reaches its final destination, a large enclosed cement tub where chlorine and ammonia are added as disinfectants, along with fluoride.

Most people don't consider the measures taken every day to ensure that drinking water is safe to drink, Nelson said.

"I think everybody should backpack and learn how to treat water," he said. "They'll gain an appreciation of the energy that it requires to move water and the fact that you have to be careful about purifying your water. ... They'll learn how precious water is and how important it is to keep it pure."

After it is treated, the water is diverted to four large pipelines, where it either flows under the bay in the new Bay Tunnel or around San Jose as it heads north up the Peninsula toward San Francisco. It is here where Palo Alto intakes the SFPUC water at five locations around the city, receiving about 10 to 11 million gallons of water per day, depending on weather and the seasons.

At the Area 1 intake station off El Camino Real near University Avenue, senior water system operator Dave Cordova checked on a large blue pump in the far corner recently. A meter just to the left read "1828 gpm." The number revealed how well the pump was working to depressurize the water to a level more suitable for urban use, sending just under 2,000 gallons per minute to all the homes and businesses east of El Camino — Palo Alto's largest water service area.

---

More than 66,000 residents and tens of thousands of employees are served by Palo Alto's water utility. Last month CPAU officials announced that new restrictions must take effect to help meet the state's demand to reduce use by 24 percent of the baseline amount from 2013. This includes limiting landscape watering to twice a week, and only in early-morning or evening hours, and replacing defective plumbing or irrigation. If residents don't comply they could face fines of $100 a day following three prior complaints.

As of this past week, Palo Alto's water consumption has been reduced from the 2013 levels by a little more than 19 percent, just 5 percent shy of the state target. Though these water restrictions may be a short-term fix for a long-term problem of preserving water supplies in lean years, Elvert said it's still the best initial step for making change.

"Conservation is the first step; it's the easiest thing to do and it's the cheapest thing to do," she said. "And then you can look at alternative water sources ... which could be much more costly and involve much more."

In the future Palo Altans may consider alternative sources such as filtered waste water, diverted groundwater from the local creek watershed or desalinated water. But that may be a long ways away and for now Elvert said people should start by considering the source of the city's water and how it flows from 167 miles away straight to their taps.

"Our water supplies are a finite resource. ... The population continues to increase, yet our water supplies are finite," she said. "And so it's really important for people to understand that and do whatever they can to protect and preserve that."

Correction: In the original article, the capacity of the Don Pedro Reservoir was misstated as 65 billion gallons. The reservoir can hold 665 billion gallons.

Comments

12 people like this
Posted by Maurice Druzin
a resident of Crescent Park
on Jun 19, 2015 at 10:32 am

This is a "must read" article for all citizens!
Recycled "grey water" should be a priority in Palo Alto.
The shower timer from the Utility is a great idea, and really does help!
A well written and informative piece, congratulations to Veronica Weber and the Weekly


12 people like this
Posted by water waster
a resident of Old Palo Alto
on Jun 19, 2015 at 10:44 am

waay too many green lawns in Palo Alto. WAAY too many. just the other day, i saw someone washing their car in the middle of a hot day on their driveway with water flowing down the gutter. that was DISGUSTING!! their car is worth more than others trying to use water for drinking. pretty soon, all we will have to drink is bottled water due to people like this.


10 people like this
Posted by mauricio
a resident of Embarcadero Oaks/Leland
on Jun 19, 2015 at 10:58 am

mauricio is a registered user.

There are many reasons why stopping over development in Palo Alto is extremely important and crucial for its survival as a unique, pleasant town with high quality of life, but this is one of the most important reasons. Every new development puts more pressure on our dwindling water supply during what seems to be a prolonged era of severe drought that may last many years or even decades.


6 people like this
Posted by Mark
a resident of Duveneck/St. Francis
on Jun 19, 2015 at 11:11 am

I don't understand why we don't have gray water systems in place everywhere in this state. So much of the water that we use is wasted & could be used to water plants, for example. Water recycling should be a priority for this state going forward. Requesting voluntary conservation only during the lean years is foolish. The state should require more efficient use of water, including the recycling of water, even when water is more plentiful. If citizens are not required to plan for water shortages & instead measures are taken to put systems in place that do this automatically, we'd be better off in the long run. Yes, this will involve additional costs, but rbis may become a necessity if these droughts continue to plague us.


3 people like this
Posted by Bob Meltzer
a resident of Crescent Park
on Jun 19, 2015 at 11:47 am

The article was very comprehensive, but it did not mention the important storage cisterns on Palo Alto property including the new storage facility opposite the Stanford shopping center on El Camino. Any comments?


11 people like this
Posted by BNord
a resident of Palo Verde
on Jun 19, 2015 at 11:54 am

Since Hetch Hetchy water is so clean and pure, it is a mystery to me why the SFPUC feels it is necessary to use the chemical chloramine (a mix of chlorine and ammonia) to disinfect our water. This chemical can cause skin, digestive and respiratory problems even tho the SFPUC will deny this. It also produces far more byproducts than plain old chlorine, most of which are not regulated. It may take a while, but I'm sure water professionals will eventually realize the problems and make a change.


3 people like this
Posted by John
a resident of Barron Park
on Jun 19, 2015 at 12:02 pm

What is the fee structure of the City's contract with San Francisco? It is difficult to determine whether or not the additional charges to users proposed by the City are legitimate without knowing how the costs to the City are attributed to the amount of San Francisco water used.


18 people like this
Posted by enough!
a resident of Charleston Gardens
on Jun 19, 2015 at 12:33 pm

Meanwhile Palo Alto bends over backwards to allow wealthy residents to build basements for new homes wasting MILLIONS of gallons of water drained from underground aquifers and spewed at hundreds of gallons an hour out to the Bay. This City is so hypocritical it's disgusting.


4 people like this
Posted by Veronica Weber
a resident of Evergreen Park
on Jun 19, 2015 at 12:44 pm

Veronica Weber is a registered user.

Thanks Bob, unfortunately with the limited space to the story I couldn't fit in much information about Palo Alto's emergency water supply. All told, the city has 7 reservoirs which can supply 13 million gallons including the new 2.5 million gallon reservoir completed in 2013 beneath El Camino Park, as well as 8 groundwater wells. The water at each reservoir is circulated throughout the system on a regular basis and chemical disinfectant levels are tested daily and has been designed to serve Palo Alto in the event that SFPUC's water is cut off.

Also, SFPUC adds the chloramine mixture to our water because state and federal drinking water regulations determine how much chlorine, ammonia and fluoride must be added to California's water.


4 people like this
Posted by Joe
a resident of Another Palo Alto neighborhood
on Jun 19, 2015 at 2:13 pm

> Unlike water supplied from other reservoirs
> and the ground, Hetch Hetchy water is so pure that it doesn't need to be filtered.


Web Link

In the near future, it is expected that Hetch Hetchy water will require advanced disinfection, as well as potentially some modification to current disinfection practices, to provide for further inactivation of Cryptosporidium to comply with USEPA’s Long-Term Enhanced Surface Water Treatment Rule.

Even with this special status for Hetch Hetchy, SFPUC actually filters much of this
supply. For example, during times when the Hetch Hetchy supply arriving in the
Bay Area exceeds system demand, Tuolumne River water is spilled to Upper Crystal
Springs Reservoir on the San Francisco Peninsula, where it is subsequently filtered and
disinfected at the Harry Tracy Water Treatment Plant. In response to seasonal water
quality problems, SFPUC also has the capability of filtering Hetch Hetchy at its Sunol
Valley Water Treatment Plant, either directly or after storage in San Antonio Reservoir.

Normally, though, Hetch Hetchy is only treated with lime for corrosion control,
hypochlorination for primary disinfection, chloramination for secondary disinfection,
and fluoridation for the prevention of dental cavities.


4 people like this
Posted by Mike Alexander
a resident of St. Claire Gardens
on Jun 19, 2015 at 4:26 pm

Until the 1960's, high-country Sierra Nevada water was essentially pathogen-free. Now, the intestinal parasites giardia and cryptosporidium are present, apparently originally passed into the water by grazing cattle. Both can cause serious illness, and chlorination is an efficient method to remove them.

Filtration referred to in the article would be used to remove particulates, but the geology of the Sierra makes it easy to collect particle-free water.


5 people like this
Posted by Maria
a resident of Duveneck/St. Francis
on Jun 19, 2015 at 5:04 pm

Last week I drove past Lytton Plaza and noticed that the fountains were running - across the side walk and into the gutter! Is that the way the City saves water???


3 people like this
Posted by Joe
a resident of Another Palo Alto neighborhood
on Jun 19, 2015 at 5:46 pm


How can drinking water become contaminated with these parasites?
Web Link

Giardia are often found in human, beaver, muskrat, and dog faeces. Cattle faeces appear to be the primary source of Cryptosporidium, although these parasites have also been found in humans and other animals. Drinking water sources become contaminated when faeces containing the parasites are deposited or flushed into water. If treatment is inadequate, drinking water may contain sufficient numbers of parasites to cause illness. Other sources include direct exposure to the faeces of infected humans and animals, eating contaminated food, and accidental ingestion of contaminated recreational water. The comparative importance of these various routes of exposure is unknown.


2 people like this
Posted by Bob
a resident of Menlo Park
on Jun 19, 2015 at 11:51 pm

How about a similar article about Menlo Park water in your sister publication The Almanac. In particular I'd be interested to know why pregnant women are advised to not drink the water in San Mateo County. Isn't our water also from Hetch Hetchy?


Like this comment
Posted by Me
a resident of Adobe-Meadow
on Jun 21, 2015 at 9:41 pm

Hetchy hetchy water source is precious. This is why I have tagged all of my irrigation system to OFF over 4 months ago. Trees will just have to fend for themselves until the drought is declared over by the Gov Brown. I could careless what the neighbors think of how ugly my property is when all the trees soon turn brown.

If no measurable storm system arrives in the near future, the next step would be to hire tree cutting Co. in bringing down tall dead ones for safety. Brown is now the new Green!


2 people like this
Posted by Curmudgeon
a resident of Downtown North
on Jun 21, 2015 at 11:33 pm

"I don't understand why we don't have gray water systems in place everywhere in this state."

This question is asked during every drought, and forgotten during every wet period.

Answer: $$$$


2 people like this
Posted by Betty Jo
a resident of Embarcadero Oaks/Leland
on Jun 22, 2015 at 10:11 am

On a 30 minute walk, we encountered close to a half dozen basement construction/pumping projects.
Water coursing through the storm drain we walked by sounded as though it was the day after a large winter rain.

Most of these construction sites have 3 inch drain pipes into the storm drains. A 3 inch pipe can move/waste 100 gallons a minute!

Just this week we hear the report that a high proportion of the world’s most critical aquifers are now in
bad shape. Yet we drain our “shallow” acquirer for residential basements - for all the McMansions being constructed to replace our liveable (and nearly affordable) family housing stock.

I respectfully suggest that the planning department STOP approving ALL basement designs for residential development. We are in a drought folks. Permitting these basement construction projects in residential is unconscionable. Our “near to the bay” community has a high water table. Every basement construction permit will flood precious groundwater into the bay. This is not ok. Planning Department: What are you thinking??


Like this comment
Posted by Betty Jo
a resident of Embarcadero Oaks/Leland
on Jun 22, 2015 at 10:14 am

On a 30 minute walk, we encountered close to a half dozen basement construction/pumping projects.
Water coursing through the storm drain we walked by sounded as though it was the day after a large winter rain.

Most of these construction sites have 3 inch drain pipes into the storm drains. A 3 inch pipe can move/waste 120 gallons a minute!

Just this week we hear the report that a high proportion of the world’s most critical aquifers are now in
bad shape. Yet we drain our “shallow” acquirer for residential basements - for all the McMansions being constructed to replace our liveable (and nearly affordable) family housing stock.

I respectfully suggest that the planning department STOP approving ALL basement designs for residential development. We are in a drought folks. Permitting these basement construction projects in residential is unconscionable. Our “near to the bay” community has a high water table. Every basement construction permit will flood precious groundwater into the bay. This is not ok. Planning Department: What are you thinking??


5 people like this
Posted by @Betty Jo
a resident of Adobe-Meadow
on Jun 22, 2015 at 11:26 am

"we encountered close to a half dozen basement construction/pumping projects."
So would that be 4?


6 people like this
Posted by Me
a resident of Adobe-Meadow
on Jun 22, 2015 at 1:03 pm

Wasting water is not because of on going basement constructions but mostly due to wasteful consumers. Drainage from the basement excavations going directly to storm drains are flowing to where? Let's take an educated guess here - it is going into the wetlands A.K.A. brackish water which has shown in studies after studies that this body of water needs replenishing contrary to common belief that the bay replenishes it 100%. This wives take is Not true especially during a long drought!

Please learn the fact and understand the big picture before jumping to conclusion!


2 people like this
Posted by Me
a resident of Adobe-Meadow
on Jun 22, 2015 at 1:05 pm

"Wives tales"


9 people like this
Posted by water dummy
a resident of Another Palo Alto neighborhood
on Jun 22, 2015 at 4:03 pm

I don't understand how and why the new construction has suddenly become the source of the problems in this drought. If the dry weather continues, a dozen basements being drained will not make a bit of difference in the grand schema of things - but the tax dollars paid by the newly minted McMansion owners would be a very needed resource for addressing the problem. I see a lot of long time property owners enjoying the benefits of this great city while paying their annual $500 tax bill, but never stopping to consider much whose tax dollars really make all this possible today.


4 people like this
Posted by Me
a resident of Adobe-Meadow
on Jun 22, 2015 at 4:43 pm

Here's an idea. Instead of spending energy whining about new constructions, why don't you take the first step in conserving portable drinking water from Hechy Hechy source by immediately stop watering your lawn, shrubs, trees ect....


Like this comment
Posted by Crescent Parkie
a resident of Crescent Park
on Jul 26, 2015 at 11:04 am

Retrofitting a home to capture gray water is expensive -which is why it is infrequently (never?) done in communities with a steady supply of piped fresh water. A temporary way to use gray water is to sign up with one of the local companies that truck recycled water from the PA treatment facility and will water your garden for you. Watering with recycled water is is an excellent use water that would other wise be dumped into the bay. Two local companies who are doing this today are RainDanceNow.com and the PurplePipes folks.


Sorry, but further commenting on this topic has been closed.

Salt & Straw Palo Alto to open Nov. 23
By Elena Kadvany | 0 comments | 3,195 views

El Camino: Another scheme to increase congestion?
By Douglas Moran | 30 comments | 2,778 views

Trials of My Grandmother
By Aldis Petriceks | 2 comments | 1,402 views

Lakes and Larders (part 2)
By Laura Stec | 0 comments | 1,148 views

Can we ever improve our schools?
By Diana Diamond | 5 comments | 428 views