Water and Wastewater Utility Resilience Cases

Continuing with the theme of Infrastructure Security Month, WaterISAC is spotlighting utilities working to increase their resilience to counter all-hazard threats.

In Portland, Oregon intense storms over the weekend caused a tree to fall on Portland Water Bureau’s Lusted Hill water treatment plant, which impacted the utility’s ability to add corrosion treatment to one of its main sources of water. To maintain continuity of service, the utility immediately activated its other water source, groundwater from the Columbia South Shore Well Field. Possessing two distinct water sources greatly increases the resilience of Portland’s Water Bureau. “Groundwater is one of our most powerful tools in planning for emergency supply response and climate change,” said Portland Water Bureau Director Gabriel Solmer. “We can expect more extreme weather events like the recent rains that have impacted the region. Groundwater allows us to reliably provide water to people when severe storms impact the Bull Run Watershed or we have other supply disruptions.” Read a press release from the Portland Water Bureau or access a relevant news article here.

In the aftermath of hurricanes and other large storms, which produce heavy flooding, traditional sewer systems are often overwhelmed leading to sanitary sewer overflows. These overflows can contaminate water supplies, cause property damage, and endanger public health. Moreover, traditional sewer systems, such as the gravity sewers, typically become inundated with water during flooding events leading to overflows and service disruptions if to much debris enters the system leading to long-term recovery efforts.

In response to this problem, many utilities in coastal flood prone areas have adopted the All-Terrain Sewer (ATS) pressure sewer system. “The ATS piping system is not subject to infiltration from groundwater or from surface storm water… In coastal flood settings, it eliminates storm water with high salinity to WWTPs so treatment efficiencies can be more consistent and operating costs decrease,” according to Water & Wastewater Digest. The Florida Keys Aqueduct Authority, for example, was able to rapidly recover following Hurricane Irma because of its ATS systems, which still functioned even under four feet of water. The Bald Head Island Utilities in South Carolina also posses 800 ATS units and, according to David Mintz, field supervisor for the Bald Head Island utility, they are easier to restore compared to gravity systems. “As far as equipment goes, it’s very important to have a reliable product that works good for us in our unique situation: Sandy, very stormy, windy, hurricanes, flooding, lots of flooding.” Read more about sewer resilience here.