Climate Outlooks Help Water Supply Planning
Withdrawing water from nature
In the early 2000s, Dr. Alison Adam’s hometown of Tampa, Florida, experienced prolonged drought conditions. As surface water became scarce, the regional water utility—Tampa Bay Water—made the decision to use groundwater to meet consumers’ needs. Pumping groundwater lowered water levels in the region’s wetlands and lakes, eventually damaging ecosystems and reducing habitat for wildlife.
When the extent of damage to natural systems became clear, Adams—the Chief Technical Officer of Tampa Bay Water—and her colleagues recognized that they needed to provide water for the environment as well as for their customers. To supply both needs, water operations managers needed forecasting tools to help anticipate potential reductions in surface water supply, so they could take steps to reserve sufficient water for ecosystems.
Tracking climate patterns
Adams focused on climate. She and her colleagues quickly learned to use outlooks from NOAA’s Climate Prediction Center to anticipate temperature and precipitation patterns weeks and months into the future. Climate outlooks are based on past weather observations, the current state of the global ocean, and computer modeling studies. A particularly important factor in Florida’s climate is the months- to years-long pattern of warming and cooling waters in the central Pacific, called the El Niño Southern Oscillation (ENSO). The state of ENSO has proven to be a reliable indicator of wet or dry conditions in Florida.
By tracking this pattern, Adams and her colleagues give water operations managers crucial insights into what they can expect from the climate system. “We have tools available to let us know how, or what’s causing these conditions to change and when these conditions are going to change,” explains Adams. Given her experience using climate outlooks, she is able to advise water managers when surface water is likely to become scarce, enabling them to make timely decisions to save groundwater and, ultimately, ecosystems that depend upon it.
Investments in infrastructure
Tampa Bay Water also took action to improve its resilience to drought by making major capital investments in water infrastructure. They built a reservoir to store surface water and a desalination plant that could supplement freshwater during especially dry periods. Today, the utility can draw from three sources: surface water from its rivers and reservoir system, groundwater from wells, and desalinated water from Tampa Bay itself. Each source has different costs, so water managers must still decide how to balance costs and supply, but the use of outlooks and the availability of new sources has increased the utility’s ability to serve its customers at the same time as it sustains local ecosystems.
By understanding ENSO, Dr. Adams makes economically and environmentally feasible decisions about water storage and withdrawal, pumping operations, and operating the desalination plant. Balancing these three sources of water so that water rates remain low and quality of life remains high is a big challenge, but climate information has made it manageable.