Imagining A Second Yosemite Valley - A Restored Hetch Hetchy - SacBee

[hatrack]

"Here's the best-kept secret of Yosemite Valley: It has a twin.
This little brother, as the late naturalist John Muir called it, has a thundering waterfall named Wapama, a feathery cascade named Tueeulala and a towering peak called Kolana. Below Kolana, a valley snakes between granite walls for eight miles to reach a staircase of rock known as the Grand Canyon of the Tuolumne.

Yosemite's little brother has a name. It is called Hetch Hetchy, derived from the Indian name for its native meadow grasses. But despite its grandeur and its presence in a park that is a national treasure, few people know Hetch Hetchy exists and few visit it.
There is a reason for this remarkable obscurity. Hetch Hetchy is underwater.

Since 1923, a dam that supplies water to the San Francisco Bay Area has submerged the valley's roughly three square miles. An act of Congress in 1913 gave San Francisco control of the valley, a precious resource that belonged to the entire nation. No wonder, then, that Hetch Hetchy is today the least visited natural feature in the 1,189-square-mile Yosemite National Park. In one survey of Yosemite's popular sites, Hetch Hetchy finished last, below "other." No other national park has such a centerpiece jewel that is locked away from the public, both by the ranger's key at 9 p.m. every day and by 300 feet of sparkling, clear Sierra water.

Yosemite serves nearly 4 million visitors a year. Someday soon it will run out of room for the public. When that day comes, the choice will be stark: Ration the chance to experience the glories of the Yosemite Valley or create, literally, more valley. Such an expansion is possible if an idea once considered fanciful, even quixotic, gains legitimacy: Drain Hetch Hetchy - an enlarged hole at the dam's base would do the job - and let nature begin to reclaim this spectacular setting.

That may sound simple, but it isn't. It would require some changes to the Bay Area's water system and a consensus among major holders of Tuolumne River water rights. But if the notion is complicated, it is not out of the realm of the possible and is well worth discussing. An upcoming replumbing of San Francisco's Hetch Hetchy system and a convincing restoration proposal generated by a new computer program at the University of California, Davis, make this an appropriate time for the conversation to begin."

EDIT

http://www.sacbee.com/content/opinion/story/10470062p-11389376c.html

[hunter]

1. Yes.

Let's just do it.

Restore Hetch Hetchy.

[Trillo]

2. How are we going to get enough water for agriculture

if and when the environment is hot enough on average that the Sierra Nevada and similar mountain ranges no longer have snowpack to melt during the spring season?

The only way I can envision is by catching more rainfall, or some kind of coastal desalinization and piping to inland areas (costly).

[NNadir]

3. I appreciate the practical response, but I have dreamed of the

Hetch Hetchy for decades.

Let me ask you this: Do they still grow rice in California?

[Trillo]

4. Is Global Warming limited to California? nt

[NNadir]

5. The argument against dismantling the Hetch Hetchy dam is about

water, not global warming, unless you are referring to the (very real) possibility that climate change will make the water moot.

If so, I have misunderstood.

I have not lived in California for about a decade, but I recall that in a former time, the agricultural use of water was rather wasteful.

Dianne Feinstein, however, as I recall as Mayor of San Francisco tried to oppose the one positive environmental initiative of the entire Reagan administration, the (tongue in cheek?) proposal to remove the Hetch Hetchy dam. She argued that the water tasted good and that somehow Hetch Hetchy water was a San Franciscan birthright.

I think that the need for desalination (not without enormous environmental and economic consequences of its own) in California is becoming increasingly obvious.

Of course, the source of California's water and environmental problems is the pretty much the world problem writ large: Too many people for too little resource.

[Trillo]

6. Yes, that is the issue I was implicitly referring to.

What does the world have right now, 6 billion people? Climate change will significantly alter how people feed themselves, and likely more people will go hungry. Long term thought about the best use of resources, including water, needs to be planned. Of course this also includes water conservation.

I know very little about water use in other countries, but don't some water their crops by capturing the rain during monsoon?

My larger point is that if the more pessimistic scenarios for climate change occur, by 2080 there will be much less snow-pack to water crops with. How to make up for this with a minimum of capital expenditure would seem to be a question for smarter people than me to consider now.

In spite of their problems such as siltation, dams could provide part of the solution. Destroying them now might hurt the next few generations who may need more dams in more waterways, not less.

[phantom power]

7. you may be right, but the reservoirs themselves won't last forever

Sooner or later, any reservoir we build will silt up. Maybe sooner than later, depending on silt load of the river.

Maybe a devil's bargain we need to make, to survive the next century. But it's a crying shame, what it will do to the world's rivers.

And when the reservoirs fill in, what then...

[Trillo]

8. "Dams could make much work for dredgers, says Dutch firm"

http://www.sandandgravel.com/news/news/news_1401.htm

[phantom power]

9. I suppose so....

I have a hard time conceiving the difficulty and cost of dredging something like the Powell Reservoir. We're talking about cubic kilometers of silt.

But that doesn't mean it's impossible. And I imagine that for the majority of smaller reservoirs, it is more feasible.

If nothing else,it would represent a significant increase in the effective operating cost of any reservoir. Dredging the silt, and disposing of it in an appropriate way, seems expensive to me.

It raises interesting questions like: If you include the energy cost of dredging, does the EROEI become < 1? It gets more complicated if you factor in the effects on the cost of water for agriculture, industry, etc.

If you add it all up, I wonder if it starts to become comparable to the cost of industrial-scale desalinization plants?