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EXECUTIVE SUMMARY
Japan has built the resilience of its water supply and sanitation (WSS) services through an adaptive management approach based on lessons learned from past natural disasters. This experience offers key insights for low- and middle-income countries (LMICs) seeking to sustain and build resilience of WSS services.
Sustainability of Essential WSS Services at Risk Natural disasters have increasingly damaged WSS facilities and infrastructure, leaving entire communities without safe and reliable drinking water and the appropriate disposal of wastewater. These emergency events could arise from inundation of facilities, loss of electricity, and exposure and disruption of infrastructures. Lesssevere impacts can arise from increased siltation of reservoirs and slow-onset events such as droughts, thus having longer-term effects on the resilience and reliability of services. These WSS service failures or interruptions could set off a cascading effect across interconnected infrastructure systems including public health and fire services, which in turn could pose both direct and indirect economic impacts.
For example, recent natural disasters that affected the utilities in Japan include the following:
• In 1978 and 1994, Fukuoka City experienced severe droughts that necessitated water rationing for approximately 300 days each.
• The 1995 Hanshin-Awaji Earthquake (magnitude 7.3) took the lives of 4,571 people and severely damaged the infrastructure; it took 10 weeks to restore piped water supply.
• The 2011 Great East Japan Earthquake (GEJE) of magnitude 9.0 led to a loss of water access among up to 500,000 residents in Sendai City, and the city’s primary wastewater treatment plant was completely submerged by tsunami.
• The GEJE had a seismic intensity at the upper-5 level in Tokyo, and led to a temporary service disruption to 42,000 residents. 12 kilometers of sewerage pipelines were adversely affected by cracks and sand clogging owing to earthquake-induced soil liquefaction.
• Multiple precipitation-induced landslides in 2014 in Hiroshima City extensively damaged the water distribution networks and other facilities, causing approximately 3,500 households to lose access to water.
• In 2016, two earthquakes of magnitudes 6.5 and 7.3 caused all residents in Kumamoto City (up to 326,000 households) to lose access to water.
Although more investment is urgently needed to improve basic water and sanitation access in LMICs, maintaining or enhancing the disaster resilience of both new and existing (particularly aging) infrastructure—especially in the context of climate change and variability—is also critical for sustainable development.