_____________
Postcard from the Sacramento Delta (2013)
5 min 40 sec — Rated G — Suspense
Director: Todd Dayton
Cast: Jay Lund, Daniel Wilson
The sea is rising and the land is sinking. Aging levees are giving way. Island communities find themselves at the mercy of forces beyond their control.
Produced by Fallout Pictures for Greenpeace’s Postcards from Climate Change
_____________
Further reading
Kelley, R. 1998, Battling the Inland Sea, Berkeley: University of California Press
Lund, Jay. “Sea level rise and Delta subsidence – the demise of subsided Delta islands,” CaliforniaWaterBlog.com, 9 March 2011
Lund, Jay. The Delta won’t rise again, CaliforniaWaterBlog.com, 17 June 2013
Moyle, Peter. “Ten realities for managing the Delta,” CaliforniaWaterBlog.com, 26 Feb. 2013
Suddeth, R., J. Mount, and J. Lund (2010), “Levee decisions and sustainability for the Sacramento San Joaquin Delta“, San Francisco Estuary and Watershed Science, Volume 8, No. 2, 23pp, August
Thompson, J. (1957), “Settlement Geography of the Sacramento-San Joaquin Delta, California”, dissertation, Stanford University
In the last 600 years California’s Central Valley region has been drying and the exportation of water out of the region has exasperated the issue. Areas of the Tulare Lake Basin have subsided much more than the areas depicted in this video due to intensive farm operations that have depleted groundwater and natural surface waters. The USGS has identified areas that have sunk more than 18 feet in the last 50 years, a much greater rate than that identified for the delta islands. It is not a new trend but a continuing trend. Rising sea levels have been seriously overestimated for years. The Dutch have been farming areas below sea level for hundreds of years and their earthen levee/dike systems are something that are admired by most of the free world. Levees can easily be strengthened and widened so that economic interests can be protected. What the delta cannot withstand is the continued reduction of water that occurs as a result of demands from farming interests in the Westlands and Southern California.
2/3 of the water taken from the Delta is taken upstream of the Delta, for Sacramento Valley, San Joaquin Valley, and Bay Area users. Most of California is to blame for the Delta’s problems, including the land users in the Delta.
The subsided lands in the Tulare and San Joaquin basins are more subsided than the Delta, but are not below sea level or surrounded by water. The Dutch levees and lowlands are quite interesting, having been below sea level for centuries. Oddly, most Dutch lands below sea level are only about 6 ft below sea level – much less than in California’s Delta. I once asked a Dutch expert about this; he replied that the Dutch subsidence has been much less for two reasons, a) the Netherlands is much cooler than California, so the oxidation reactions are much slower and b) many of the Dutch lowlands are regulated to keep the water table much closer to the surface, which reduces both subsidence and crop yields. Dutch levees also have a huge advantage/disadvantage over California’s Delta levees – Dutch population densities and crop values are much much higher than in the more subsided parts of California’s Delta, so there is much more economic justification and ability to pay for strong levees. But if a levee fails, there is much more to lose in the Netherlands.
Very interesting and timely information.
If writing to legislators or as an LTE remember to write that the exportation has EXASERBATED(made it worse) the issue,
not exasperated(annoyed) the issue
You could also say aggravated
We do want to sound credible and all that.
So, just hypothetically speaking, if a new ice age were to begin, then sea levels would drop, the soft beds of the streams passing through the delta would erode, lowering the water table, allowing the peats on the islands to dry out and vaporize, further lowering elevations on the islands, creating a different sort of water problem. Before the Sierra Glaciers formed, ice dams would occasionally/seasonally form in the mid elevation river canyons, nicking large slides, then burst carrying tons of sediment that would quickly overwhelm the rim dams. Sediment loads would increase filling in some of the volume lost to respiration. Then in another 20- 100K years the glaciers would melt bringing more sediment down to fill the confluence and Southern land locked basins, raising sea levels and creating a new delta and lakes for humans to set up the whole dysfunctional system all over again. Right?
Excellent video. Thank you for your effort.