Hetch Hetchy Reservoir

Today we got up early to get a tour of Moccasin Power Plant, which uses water from the Hetch Hetchy Reservoir. Our tour guide brought up the fact that hydropower is one of the most efficient forms of energy production. It is available 24 hours a day whereas solar is only efficient during sunny days and wind is only efficient at night when energy is not needed. The only problem they have is that at night they make too much energy and have to pay people to use it. I think that it would make more sense to build a pump storage facility and use the energy they would normally have to pay people to take and pump water with it and they produce even more power during peak hours. The reason that that has not happened is energy is not the reason the reservoir is there, it can conveniently produce power but the reservoir is there to manage water. The main purpose it to ensure that San Francisco receives between 220 and 290 million gallons of water a day. That number is simply outrageous and San Francisco still needs more water than that. The water is transported more than 140 miles from an elevation of of 900 feet to 325 feet all by gravity. I wonder if adding small turbine inside the pipes to create extra energy would be possible.

The main controversy with Hetch Hetchy is that it is in Yosemite National Park. The park is suppose to protect and preserve but it has an unnatural reservoir in it. I would rather the reservoir not be there to make Yosemite as pristine as it could possibly be, but I understand that it is not possible to remove it. The ecosystem is adapting to the reservoir and removing it would leave an uglier scar then what the reservoir is now. It is crazy to think about how beautiful Yosemite Valley is and Hetch Hetchy is the exact thing filled in with water. So it is kind of sad to think about what beautiful landforms are buried under all of that water.

There is a positive though, since the headwaters of Hetch Hetchy are in the National Park they are pristine. That means that they are very clean and have a low sediment load. So they are able to have a filtration avoidance which is good because the water will be pure and cheap but is a little scary. That means from the spring to your tap the water is only chlorinated. There are a lot of harmful things that are not killed by chlorine but would be removed by a filtration system. So far it has not been a problem but it would not take a terrorist very much to poison the entire San Francisco water supply and by the time it is caught 2.5 million people could be dead.

Picture Citations:

"O'Shaughnessy Dam." Anthony Sarnoski. 2011.

"Hetch Hetchy Reservoir." Anthony Sarnoski. 2011.