Predicting the Impacts of Climate Variability on Florida
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Since 2008, Tampa Bay Water has been working nationally and regionally to understand the impacts of climate variability on its water supplies so it can adjust and adapt to meet demand. With half of the region’s supply coming from river water, which is directly linked to rainfall, understanding how climate variability affects supply reliability is crucial to future planning.

To further our knowledge on climate change, Tampa Bay Water is part of the Water Utility Climate Alliance (www.wucaonline.org), a national group comprised of 10 major water utilities across the country. This group is focused on actionable science: data, analysis and forecasts that are predictive and can support decision-making on things like capital improvements.

While the national group is making significant strides, Florida requires models and predictive tools that meet our specific needs and take into account our unique rainfall patterns as well as sea level rise. The Florida Water and Climate Alliance is working to meet Florida’s needs.

Funded by the National Oceanic and Atmospheric Administration (NOAA), the Florida Water and Climate Alliance (www.floridawca.org) is evaluating global climate models to determine their applicability to Florida with respect to predicting temperature, rainfall and the impact of future climate scenarios on water supply availability.

The group’s members include the University of Florida Water Institute, Florida State University, three water management districts, Tampa Bay Water and five other major public water supply utilities, plus several cities and counties.

Through research supported directly by Tampa Bay Water, researchers have downscaled rainfall and temperature outputs from global climate models for local and regional analysis of hydrologic systems. The research shows that for a given carbon emission scenario, global climate models are better at predicting temperature change than changes in rainfall.

The research also shows that the method by which researchers translate (downscale) global climate model output to local and regional scales is important for water supply planning in Florida. Additionally, regional hydrologic models are necessary to understand changes in hydrology due to climate. 

This research is using Tampa Bay Water’s Integrated Hydrologic Model to assess changes in hydrology due to climate for Tampa Bay Water’s service area.

Downscaling efforts yielded results specific to the Tampa Bay region. Based on the evaluation of three global climate models, temperatures are consistently estimated to increase by 2-3°C in the 2039-2069 timeframe. However, rainfall predictions are inconsistent and range from 22 percent less rainfall to 11 percent more rainfall.

Both groups continue to develop and refine predictive tools. The Florida workgroup will continue downscaling refinements to the global models in order to quantify the uncertainty in temperature and rainfall projections for Florida as well as evaluate how climate change could affect water supply availability for the Tampa Bay region.

To learn more about how we use climate information in water supply planning activities, check out these videos developed by NOAA and Tampa Bay Water.

Sources and Cycles: Balancing Water Needs

Worried about Water? Tracking Climate Assures Supply