Saturday, November 29, 2008

Water Storage & Global Warming

This article from the Bee points to a terrific idea for storing water underground and a storage technology that most certainly needs enriching.

With the current possibility of raising Shasta Dam 200 feet—to the height to which it was originally engineered—we could triple the storage there to about 13.8 million acre feet.

With the building of Auburn Dam—one of the few dams that could still be built in California—we could add another 2.3 million acre feet.

With the 10-50 million acre feet of underground storage envisioned by Professor Fogg, California would be realizing the level of water storage needed to not only provide for the existing needs of the state but also much of the future needs, even with the results of a reduced snow pack due to global warming.

An excerpt.

“The likely effects of climate change on local water resources in places like Sacramento are still being researched by climate and hydrologic scientists, but one thing is fairly certain: There will be less snow in the Sierra Nevada in the coming decades…

“Currently, the state has no working storage alternative that would adequately compensate for declines in the snowpack. One approach is to build more dams and raise the heights of existing dams, but there is a consensus that the problem cannot be solved solely by augmenting surface storage.

“Subsurface storage is a tantalizing alternative and could be vastly increased if certain technical hurdles and limitations in our knowledge of the underworld could be addressed.

“The tantalizing part: Currently there is space for storage of an additional 10 million to 50 million acre-feet of water in the Central Valley, one of the largest aquifer systems in North America. For perspective, consider that the combined capacity of our four largest reservoirs (Shasta, Oroville, Trinity and New Melones) is 13 million acre-feet. Some subsurface storage and recovery of water have already been done in the Central Valley, but the time has come to adopt a grander vision on how to better use this vast below-ground reservoir on a regional scale.

“The technical hurdles part: Water percolates slowly into most aquifer systems. To capture more winter runoff and move it underground will either require new reservoirs to hold the water while it is doled out to spreading basins or a way of optimizing how water soaks into the earth. The latter has not been seriously considered but, I would argue, becomes plausible with greater knowledge of the subsurface "anatomy."