The diagram below from an illustrated study from Japan shows the immediate and longer term impact on sanitation when an earthquake damages water and sewer systems, causes building collapse and disrupts traffic.
Sewers Float and other aspects of Sewer Performance in Earthquakes has illustrations of damaged sewer lines and wastewater treatment plans in a number of US and Japanese cities. Since water pipes must be able to withstand both pressure and soil loading, they are much stronger than sewer pipes which only need to withstand soil loading. While water plants are generally built on competent soils, wastewater treatment plans are often built on fill where there is greater risk of liquefaction.
The Earthquake and Hazards Program of the Association of Bay Area Governments has information specific to water and wastewater treatment plants on liquefaction, landslides, location of active faults and details of infrastructure in hazard areas. Seismic Assessment and Design of Sewers is webinar on earthquake hazards and their impact on wastewater collection systems by Donald Ballantyne, an engineer who has worked on systems in Vancouver BC, Seattle, Portland and SanFrancisco.
Compost Toilets: Their Use as an Emergency Response in Curchchurch. Gary Williams of the New Zealand Permaculture Emergency Response Network writes about his group’s voluntary response in Christchurch after the damaging earthquakes to bring information they had about compost toilets to people who were unable to use their flush toilets because of the damage to the centralised city sewer system.
Let’s pre-think what we’d do in an earthquake that impacted sewers and made roads impassable. When asked how they would relieve themselves the event an earthquake made conventional toilet use impossible for three days, 90% 0f Japanese office workers said they would either go outdoors in an alley or relieve themselves indoors and bag it in paper or plastic. A bit of creative discussion would have generated better options, ones that put public health less at risk.
With collapsed bridges and destroyed infrastructure, authorities will be unable to respond. We need to prepare at the household and neighborhood level. Says James Roddey, former Oregon Department of Geology Information officer: Ultimately, preparedness is a personal responsibility. When we get the big one, nobody is riding in on a white horse to save you (think Katrina); in fact 80% of all rescues in an earthquake are done by your neighbors. The place to start is talking with our neighbors, imagining scenarios in ways that stimulate not fear but creativity and ultimately inspire an sense of community resilience.
At the same time, we need to get our failing sewer infrastructure and growing problems with sewage sludge on national, state and local agendas. Billions needed to upgrade America’s leaky water infrastructure says the Washington Post (January 2, 2012). With it sewage outfalls into nearby waterways and 450 sewer pipe breaks annually, Washington DC is typical of most older US cities. Problems are exacerbated by citizen ignorance. Says DC utility general manager George Hawkins “The customer base really doesn’t know. Like when I turn on the faucet, what on Earth is needed to deliver that water? It’s like magic. And then it goes down the drain. It’s like magic again.”
