Water and wastewater systems are a vital aspect of our daily lives, and any upset to these systems can have a ripple effect that impacts entire communities. That’s why it’s essential for water utility companies in earthquake zones to understand the threat these disasters pose to their systems and adequately prepare for emergency situations. To minimize damage and decrease recovery time, municipalities need to take an active role in earthquake preparation. 

Underground pipes are particularly susceptible to damage from shifting earth. Almost half of the U.S. population lives in an area that is vulnerable to earthquakes. Here, we present simple and tangible ways to prepare for earthquakes.

How do earthquakes pose a threat to water systems?

While it’s true that the West Coast is particularly vulnerable to earthquakes, they can happen anywhere. To determine how likely one is in your region, check out this useful seismic hazard map. Water infrastructure in areas with high seismic activity is vulnerable to many different forms of ground movement, including:

• Shaking and ground displacement, which can move ground vertically or horizontally and tends to cause more damage in areas with soft sediments (as opposed to mountainous regions).
• Liquefaction can happen to ground that is already heavily saturated with liquid, usually near a river or lake, and can cause water pipes, buildings and other structures to sink.
• Lateral spreading can sometimes occur after liquefaction when the liquified ground travels down a slope, creating large fissures that can be hundreds of feet deep.
• Settling occurs after an earthquake has caused a change in elevation and can greatly impact systems that depend on gravity flow.

How can municipalities prepare for earthquakes?

Pipe replacement - It’s still common practice in the U.S. to install nonseismically designed pipes, even in high seismic zones. In order to prepare for the future and avoid earthquake damage, water utilities should consider replacing their pipes with those developed to withstand seismic activity. Some municipalities opt to replace all of their pipes in order to mitigate potential earthquake damage. However, due to high replacement costs, this approach may be impractical for certain budgets.

According to the EPA’s Earthquake Resilience Guide, it may be more prudent to anticipate a certain amount of damage and establish a recovery plan than attempt to prevent any damage at all. In order to repair or replace your pipes in a timely and cost-effective manner, it’s important to keep track of their location, their age and other factors that might contribute to their performance. Asset management software can be a very useful tool when managing water infrastructure and determining the most effective replacement plan.

Assess potential damage - To accurately assess the potential damage to your water infrastructure during an earthquake, follow these steps:

• Create an inventory of your critical assets: pipes, storage units, treatment facilities, etc.
• Determine your threat level by locating your assets on a seismic hazard map. Work with engineers to do a seismic study.
• Evaluate the threat based on the geography to determine whether your assets are likely to suffer from shaking, liquefaction, lateral spreading or settling. When assessing the vulnerability of pipelines, remember to consider their location, age, compatibility with soils, construction materials and the number of joints.
• Identify the consequences of any damage to these critical assets, whether they be power loss, health hazards, fires, time for repairs, or a need for tools required for repair and emergency drinking water.
• Summarize your findings in order to create your earthquake resilience plan.
• Communicate and share your earthquake resilience plan with the community in order to set realistic expectations on post-earthquake response time and hazard preparation policies.

By tracking this information with asset management software, it’s easy to keep tabs on different assets and their various vulnerabilities. Creating a viable earthquake resilience plan is incredibly important and having all your information in one place allows you to quickly determine the potential damage, the economic impact and what you’d need for an efficient recovery.

Set mitigation goals - There are currently no federal- or state-mandated performance goals for municipalities, meaning there is no measure to determine how prepared you are for damage recovery. Recovery time is the amount of time it will take to get critical assets back to working order after a natural disaster. While a short recovery time may seem like the most logical goal, it might not be the most practical. For example, a 72-hour recovery time would incur significant costs, while it may be just as effective (and more fiscally sound) to balance mitigation and preparedness.

By determining the vulnerabilities of your assets and considering your long-term fiscal responsibilities and goals, you can set reasonable targets for recovery time, materials inventory and emergency services. In order to ensure that water and wastewater infrastructure is prepared to handle an earthquake, set mitigation goals in the following categories:

• Immediate life safety. Protect your employees, the public and the environment from immediate threats.
• Key systems in hazard areas. Reinforce your water infrastructure and address liquefaction and fault lines.
• Specific assets. Pursue different mitigation options based on the specific hazards in your area.
• Emergency response. Plan for your response and maintain necessary assets.

Remember, damage is unavoidable in a major earthquake; the goal is to be prepared to respond to it. Using WinCan asset management software to track your wastewater infrastructure, you can understand which sewer assets are your most critical, which ones intersect with faults and other geologic features, and which are particularly susceptible to damage due to age or material composition.

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