Hetch Hetchy Regional Water System | Science In The City | Exploratorium

The drinking water provided for San Francisco and many nearby communities is among the purest in the world. Located high in the Sierras, more than 200 miles away, Hetch Hetchy reservoir holds most of this water which is fed by springtime snowmelt via the Tuolumne River. The system for delivering that water is almost entirely gravity fed, requiring almost no fossil fuel consumption to move water from the mountains to the tap. Take an exclusive tour with the San Francisco Public Utilities Commission (SFPUC) as they lead us through this unique system and address the current drought and how to conserve water.

[pjf]

I was 9 years old and camping with family over summer vacation at Yosemite when a visit to cherry lake yielded a interesting discovery. Upon my first cast into the lake with power bait wadded onto a hook, it took but 2 seconds to hook a rainbow trout! Literally as soon as that sparkling ball of fishy smelling goo hit the water I was reeling in that fish which I quickly handed off to my Dad to remove from the hook and toss back. My siblings were but jealous of my accomplishment as they tried in vain to do as I did to no avail. It wasnt to be that day as I stood back and lent my assistance to their remedial skills as wannabe anglers to my now professional expertise as a seasoned pro who had landed the stocked whopper. I sat back and imagined myself a man smoking a cigar looking at nudie magazines, swearing and using the "F" word every other one swigging my beer and telling stories of the many women I'd had that week and the many more awaiting my return from this vacation. It was a grand day as I sat there imagining how I was a man. Once school was back on in late August I told of my tale and probably swore I was having women and smoking cigars drinking beer and I absolutely did use the "F" word because I had been already since preschool thanks to young guns and robocop. But my first real fish that wasnt a bluegill or crappie that made me a man and a horrible liar was there at cherry lake. Those women though boy, they sure got it good from that kid in my kind. Real hard and good from a young Johnny Holmes. Robust and stiff was I because I caught myself a fish. Oh yes, a fish. Thank you cherry lake for my cherry was surely popped upon those rocky shores that summer in 89

[jgknearlax]

...great video – I'm sitting here in LA and I got curious about how San Francisco gets its water and this video informs and educates you in s snap...now I'm an expert on San Francisco water... : )

[restorehetchhetchy]

It is good for people to learn about their water systems - and both the SFPUC and the Exploratorium should be commended for helping to make this education available.

But people should understand that a spectacular glacier carved valley, famously compared to Yosemite Valley, was destroyed to make Hetch Hetchy Reservoir possible. San Francisco is the only city ever allowed to destroy a significant part of a national park. Restoration of Hetch Hetchy can be achieved with relatively modest system improvements - far less than what other California water agencies have done to lessen their impact on the environment. See www.hetchhetchy.org for more info.

[solafide]

Sad that they did that. They didn't have too.

[oblisk]

This dam should never have been built, SF promised trails and roads to access the lands. They havent after a hundred years. Built this right in Yosemite National park before it was established and destroyed tons of native land and ecosystems. Good old california.

[TheFarmanimalfriend]

The level of arrogance to dam Hetch Hetchy can not be matched. 😪😢☹

[andrewgibson]

It's quite an impressive piece of engineering and a beautiful dam

[DavidElzeitsinfill]

Understanding the problem so we can understand the solution. Regional mega drought in the southwest, caused by a lot of things but essentially more water is being used and is in one way or another moved out of the region then the amount of water that is re-entered into the region. Conservation has its place but it is not a solution to this problem. The demands on water will not abate without causing complete collapse so the only alternative is to introduce a new source of water. Drawing water from other regional rivers like the Columbia or the Mississippi or Missouri would only move the problem around, draining other regions. The only essentially inexhaustible source of water is the ocean.
One thing we need to do is move water from the ocean back inland to places we need it and if we can do that while generating clean energy we have a chance to mitigate climate change and still have a prosperous future. It is really, really hard but it is not impossible.
If I could explain my idea in an equation it would go something like. (seawater from the west coast moved inland + converted by combination geothermal/desalination projects = clean water and clean energy.) The biggest idea I am trying to express is tunneling aqueducts from the coast, in this case the west coast of the USA inland to feed combination geothermal power and sea water desalination plants. The idea seems to be so big that no one has considered it possible but I believe it is not only possible but it is necessary. For over a century the fossil water contained in aquifers has been pumped out to feed agriculture, industry and municipal water needs. The natural water cycle cant refill fossil water deposits that were filled 10, 000 years ago when the glaciers melted after the last ice age. Without refilling these aquifers there is not much of a future for the region of the United states. As a result ground levels in some areas of the San Joaquin Valley have subsided by more than 30 feet. Similar fossil water depletion is happening in other regions all around the world. TBM and tunneling technology has matured and further developments in the industry are poised to speed up the tunneling process and it's these tunnels that are the only way to move large volumes of water from the ocean inland. The water is moved inland to areas where it can be desalinated in geothermal plants producing clean water and power. In many cases the water will recharge surface reservoirs where it will be used first to make more hydro power before being released into rivers and canal systems. It's very important however to not stop tunneling at these first stops but to continue several legs until the water has traveled from the ocean under mountain ranges to interior states. Along the way water will flow down grade through tunnels and rise in geothermal loops to fill mountain top pumped hydro batteries several times before eventually recharging several major aquifers. What I am proposing is essentially reversing the flow of the Colorado River Compact. Bringing water from the coast of California first to mountaintop reservoirs then to the deserts of Nevada and Arizona and on to Utah, New Mexico, Colorado and Wyoming. This big idea looks past any individual city or states problems and looks at the whole and by using first principles identifies the actual problem and only solution. Thank you for your time, I would like the opportunity to explain in further detail and answer any questions.

[DavidVitrano]

My best idea is to build and install Desalination Plants, along the States Coastline and Sacramento River.
So this place can come back, for all of us to enjoy

[Lazris]

I understand water is a valuable resource in California, but making a dam in a national park is unacceptable. I'd rather people in san Francisco either use less water with either quotas or pay higher prices. My choice is for the city not to have grown as large to need this reservoir to survive. I don't care about other dams on other rivers. You can dam everything except those rivers and areas chosen to be left in their natural state for our enjoyment. This needs to be removed.

[DavidVitrano]

Just use Cherry Lake and Lake Elsinore as San Francisco County's source of water and bring Hetch Hetchy back to life.

[adolfosantana]

His explanation and wording of their water rights was a little confusing if not purposely

[MRtacoma]

That dam shouldn't exist.It doesn't need to.

[michaelburt]

Sadly there are still some well intended people who want to abandon the system by tearing down the main damn. Fortunately clear heads prevailed and in recent years several upgrades to the system and damn have extended its life for several generations to come.