Governor Jerry Brown proposes to build two tunnels under the San Joaquin River Delta at a cost of billions of dollars. The tunnels’ sole purpose would be to move water. They would have no effect on storage capacity.
We’ve already advocated desalinization plants to make water instead of building tunnels to move water. There’s also a better way to control floods and store water in the Great Valley.
In 1846, you could take a riverboat from San Francisco to Bakersfield via the San Joaquin and Kern Rivers. Then, the valley had numerous lakes, ponds and wetlands. Some were year round and others existed seasonally. In the wettest years, the San Joaquin River sometimes became as wide as ten miles!
Over time, lakes, ponds and wetlands were drained for agricultural use. During years of heavy rain, more and more water was sent down Central Valley rivers to the ocean. Less water was retained in the valley. The removal of natural water features reduced the amount of available water in dry years. Dams were built in the Sierra Nevada that partially offset the loss of water features in the valley and reduced flooding.
Farming continues in some of the natural basins, such as the historic Tulare Lake. However, one third of the land in the Great Valley is no longer arable due to a variety of causes ranging from lack of water to changes in soil composition. The Valley has probably passed its peak in agriculture productivity and is starting to slide downward in sustainability because of the exhaustion of water resources and dubious land use decisions of the past.
Draining natural water features has caused a faster drop in water tables in much of the valley, resulting in a drier environment.
A Simple Proposal
Each county of the Great Valley should examine the original maps of its respective land areas to study the historic water assets of lakes, ponds and rivers. Look at the basins and historic flood patterns. Determine possible locations for water storage and diversions into the basins. Exam the productivity of the farm land in the locations and consider the potential for water storage.
In wet years, allow the historic basins, the lakes, ponds and wet lands to flood. Although the flood will inundate some agricultural land, the flooded land will rejuvenate while out of production. In the drier years, the lakes and ponds will dry up, freeing the fallowed land to be used again for agricultural production. In some cases, a determination could be made to keep land permanently flooded.
Large basins, such as Tulare Lake, can be filled with large quantities of water in wet years. The loss of farm land in the basins will be relatively small compared to the increased water storage potential.
In the San Joaquin River Delta, the island tracts that are most vulnerable to flooding can be converted for storage of fresh water.
The proposal reduces the damage done by flooding in wet years. In 1997, millions of dollars in damage was done to the Modesto urban area when Lake Don Pedro had to release water when the dam overfilled. Had the dam released water earlier in the rainy season to downstream storage areas in the San Joaquin Valley, the flooding could have been avoided completely. Wherever there has been historic urban flooding, proper storage facilities in the Valley can take the pressure off the dam system.
More water storage will put more water closer to agricultural lands in need of irrigation. Storage would be located closer to the existing Central Valley Water Project.
More storage will reduce the risk of urban damage from flooding in the event of a major earthquake. The more water retained behind mountain dams, the greater the damage risk downstream from those dams. For example, if Don Pedro Dam were to break, the entire city of Modesto could be covered with up to 15 feet of water. The more water that can be stored downstream from the dam, the less potential damage.
A Valley water storage system can store more water at a much lower cost compared to dams. If one looks at a map of the numerous basins in the Central Valley, the potential storage areas are much greater in volume than the present system of dams in the mountains.
Water storage is almost certain to raise the water table, reducing the cost of wells and pumping. A water table rises more rapidly next to a large water source than through an aquifer that has to travel miles from the source to replenish ground water.
Wildlife in the Central Valley will be reinvigorated, with more opportunities for fishing and water recreation, especially during wet years.
How to Do It
Valley water storage can be increased incrementally. As potential locations for water storage are identified, they can be filled during the wet years. The program can be implemented as money becomes available through water district revenue, bonds, or taxes. If money can be found for the expensive and poorly conceived twin tunnel project, this proposal should be much easier to implement. The plan can be locally controlled, financed and administered.
Whereas a large dam can cost upwards of a billion dollars and requires federal and state oversight, numerous small storage ponds can be created locally at relatively low c