How are statewide forecasts for water demand made in Florida? That was one of my jobs when I was the Administrator of the Office of Water Policy for FDEP. It was easy: add up the five separate water management district forecasts. To my regret, it turned out to be a lousy way of making forecasts.
For example, the October 1999 “Annual Status Report” on regional water supply planning said that water demand was 7.2 billion gallons a day and would increase to 9.2 billion gallons a day by 2020. Wrong, wrong, wrong. This is demonstrated in the December 2012 version of the annual report which says that current annual demand was only 6.5 bgd and that year 2030 demand (ten years later) would 7.9 bgd. Florida is still forecasting a lot of demand growth despite the failure of the previous predictions.
Because elaborate water supply plan forecasts prepared by the water management districts have been wildly inaccurate, we are forced to rely on common sense(!). Obviously, some areas will see demand growth. Others must reduce withdrawals to restore Florida springs and minimize saltwater intrusion. For total statewide demand, I believe that water use twenty years from now will be about the same as today. For a bunch of reasons:
- Per capita trends of reduced water use show no sign of slackening.
- Urban uses still have a lot of unused potential for improving efficiency.
- The population of Florida will not increase as fast as the current forecast.
- Higher population densities will reduce the acreages of irrigated grass.
- Eventually, the legislature will require efficient landscape irrigation and enact a water-efficient plumbing code.
- Significant acreages of irrigated agriculture in Florida will be displaced by urbanization, which tends to use less water per acre than irrigated crops.
- Citrus diseases will continue to shrink citrus acreage. (A 30% reduction since 1996.)
- A reformed sugar program might even be created that would both save consumers money and reduce south Florida water use.
That’s the story of future water supply, as I see it. Water quality is different. Just as was recognized in 1971, “Water quality is a far graver problem in the long run than is water quantity.“