California Association of Sanitation Agencies

Even if greenhouse gas emissions were to cease today, the consequences of climate change will still be felt, as the planet is already on a path toward an altered climate system. Projected impacts to wastewater and stormwater systems include effects on effluent water quality, infrastructure and operations flood protection, and increased wet weather challenges. As the sea level rises—an expected 0.6 to 1.4 meters for the California coast—and storm surges increase in coastal areas, facility outfall elevations may need to be increased. Increased inland flooding events will put critical infrastructure and service at risk. Changes in frequency and intensity of extreme storm events will create a need to reduce infiltration and inflow into sewers.

California wastewater agencies are already starting to see many of the effects of global climate change, such as significant rainfall events combined with storm surges in the winters of 2009 and 2010 that stressed sewer and stormwater systems and resulted in flooding in areas. While many sectors contribute to climate change, it is the water sector that will keenly feel the impacts of climate change—and thus where adaptation must take place. A study by the National Association of Clean Water Agencies and Association of Metropolitan Water Agencies estimated that through 2050, the infrastructure and operations and maintenance costs for U.S.-based drinking water and wastewater utilities to adapt to climate change (above expected replacement costs) will range from $448 billion to $944 billion.

CASA and the California Wastewater Climate Change Group are tracking and engaging in statewide and national dialogues related to water sector climate change adaptation. These include the California Climate Adaptation Strategy and CalAdapt, as well as EPA’s Climate Ready Water Utilities Program.

2009 CA Adaptation Strategy.pdf