Study Examines Climate Change’s Effect on Drinking Water Supply and Quality
AwwaRF began sponsoring research to assess and plan responses to the impacts of climate change as early as 2003. The studies, summarized in the 2006 report Climate Change and Water Resources: A Primer for Municipal Water Providers, give water providers a realistic grasp on the nature of the risks posed by climate change.
Research done on behalf of the Foundation’s 900 water utility members concludes that the climate scientists agree overwhelmingly that climate shift is occurring more rapidly than can be attributed to natural causes. Among the first and most critical impacts will be changes to precipitation patterns around the world in this century. This will directly affect the availability of drinking water and the water used in our homes (bathing, cooking), as well as water needed for agriculture and food production.
Key conclusions on climate change reported include:
• Global rain and snowfall will likely increase as temperatures rise, but not uniformly across the planet. Such variation makes contingency planning difficult.
• Global precipitation will likely be less frequent but more intense, leading to risk of flooding.
• As the globe warms, more precipitation will fall as rain, rather than snow. Snow packs will decline, and warmer temperatures will begin the melt season earlier. Rain will replace snow, and rain falling on snow sets the stage for greater winter and spring runoff, and a risk of floods.
• As temperatures rise, periods of drought will increase. Droughts lead to greater likelihood of forest fires in forested areas as an earlier loss of snowpack, drier summer soils and stressed trees become fodder for fires.
• Rising temperatures are expected to lead to rising sea levels, which impact coastal area water quality.
What does that mean for our drinking water, and water utility planning?
• Droughts, flooding and forest fires can have severe impacts on water quality. Droughts lead to greater accumulation of sediment in existing reservoirs; while floods and forest fires lead to severe sediment and debris flows to downstream water sources.
• Changes in snowpack, the melt season and runoff can aggravate deficiencies in storage capacity. Water utilities may have to invest in greater water storage capacity as runoff levels become more extreme.
• Rising sea levels threaten coastal area drinking water as salt-water intrudes on freshwater aquifers; as sedimentation patterns change, and as new levels lead to severe storm-surge flooding. These changes will likely affect water utility infrastructure.
• Weather change, and warmer temperatures, could lead to increased demand for industrial, municipal and agricultural water.