Natural disasters usually have adverse effects on the water distribution system, as we have recently witnessed in several states. Here are two examples of cities trying to cope with earthquakes:
How an Earthquake Affected Napa’s Water Mains
In 2014, the city of Napa, California, experienced a 6.0 Richter magnitude earthquake, causing equivalent to a year’s worth of water main breaks in just six days. Damage continued for another six months with a very high break rate. Three years later, the city has recovered main flushing and is working on attaining FEMA funds to fund construction projects.
Disaster Preparation Ongoing in Vulnerable Northern California
San Francisco Bay Area agencies are making progress with a $113 million project aimed at bolstering water supplies for crisis situations. San Francisco Bay Area water utilities aim to tap an aquifer 500 feet underground as an alternative to surface water sources in the event of an emergency.
The agencies recently provided local media with an up-close look of the drill rig currently at work trying to tap into the aquifer. This coincided with the 26th anniversary of the Loma Prieta earthquake, the very type of disaster that can create water access issues. Officials hope these groundwater wells will also be able to function after an earthquake.
The SFPUC (San Francisco public utilities commission) is partnering with Daly City, San Bruno, and the California Water Service Company on the project, due for completion in 2018. Surface water from the Hetch Hetchy Reservoir remains the primary source in the area, but in severe drought conditions or a natural disaster like an earthquake, the aquifer will be available, maintaining water supply.
The project is part of the SFPUC’s $4.8 billion Hetch Hetchy Water System Improvement Program. The program consists of more than 80 projects with the goal of building water infrastructure that can withstand seismic activity. To a large extent the project was initially designed with drought in mind, but aquifer access provides a local supply in case there is a disruption to any transmission lines.
The Hetch Hetchy Reservoir, a major surface water source that lies 167 miles into the Sierra Mountains, crosses three major seismic faults. SFPUC invested $4.8 billion to create a system to resilient in the face of seismic activity, as one of the goals of the system is to diversify water supply and look at ways of utilizing groundwater.
The main message in the water industry is diversification. Californians used to be almost 100 percent dependent upon surface water and now groundwater may offer a resilient alternative.