We live with earthquakes. Relying on imported water does not make us more secure. Common sense and science tells us our local supplies and local ground water basins are our savings account.
Impact to Water Supply
As part of the scenario work, the USGS and Caltech convened a panel of water supply experts on July 31, 2007, to determine the potential effects that the major earthquake will have on water supplies. Members from the Water Replenishment District of Southern California (WRD), the Metropolitan Water District of Southern California (Met), Los Angeles Department of Water and Power (LADWP), and others participated in the half-day session. The panel was asked questions about what infrastructure was in jeopardy (pipelines, water tanks, wells, aqueducts, reservoirs), how the damage would be assessed, how repairs would be conducted, how long water supply outages would occur, and where emergency water supply sources could be obtained. Some of the conclusions were:
• Fault movement will likely cause major damage of the infrastructure crossing it, including the main aqueducts bringing water to Southern California from Northern California and the Colorado River. Repairs may be hampered due to damaged roads and large scale-fires.
• The most severe damage will be closest to the fault, but even in the Los Angeles area there will be damage to pipelines and other infrastructure due to intense shaking. In addition, the Met / LADWP outages from aqueduct damage will impact the local water supply.
• In the first few days after the quake, there may be no water available due to infrastructure breaks and loss of power. After that, repairs will bring supplies online slowly. Each agency will be busy with their own systems, and repairs may take weeks to 6 months or more. New water pipelines may be in very short supply, as they are not in stock and will need to be manufactured.
• A “Potable Water Plan” should be devised to describe to the public how to use water during the first few days of the emergency, when treatment plants may be offline. Avoid “Boil Water Orders” because gas lines in homes may be ruptured and people with gas stoves may cause unintended explosions. Instead, a “Purified” or “Bottled” water order should be made to emphasize drinking treated water instead of boiling it.
Groundwater Basins – Our Emergency Reservoirs
To paraphrase one panelist, “The groundwater basins are our savings account and can help us get by during this emergency. They can be tapped to make up the water shortages when imported supplies are unavailable.” Met agreed and will request that groundwater users take more during an emergency to reduce the imported demand.
See: Surviving “The Big One” – Water Supply Recovery After A Major Southern California Earthquake
WRD Technical Bulletin Volume 12, Spring 2007