Tropical Storm Fay provides relief for South Florida water supply.

Tropical Storm Fay's unusual route across the center of the state could turn out to be the best thing to happen to South Florida in some time.

That's because one of the region's main drinking water source, Lake Okeechobee, is getting a much-needed top-up.

After two years of drought which saw the lake fall to five feet below its normal average, the lake level is rising dramatically this week, according to officials at the South Florida Water Management District. As more rainfall flows down from the north in the coming days, Fay could turn out to be a huge gift from Mother Nature. As Fay did not pack hurricane force winds, this also means that the lake bottom was not churned up. In the past this has led to blocked pumps.

As of Wednesday an estimated five to six inches of rain has fallen over the lake itself in the last 24 hours (see rainfall tables). Rainfall gauges in some areas are off the charts - as high as 1,730 per cent above normal for the past 48 hours.

The U.S. Army Corps of Engineers, which co-manages the lake with the Water Management District, estimates that Fay could eventually push the lake to 12.5 feet above sea level. That is more than one foot higher than the lake's level of 11.34 feet before Fay arrived. (Normally, the lake is supposed to rise to 15.5 feet at the peak of the wet season, dropping back to 12.5 feet during the dry season.)
When I last checked at 4pm Wednesday the lake level had already risen to 11.80 feet. (UPDATE: It rose to 13.63 feet by Aug 26 and  14.95 feet by Sept 6 )

The lake is the primary source of water for surrounding sugar and sod farms, and is also an important backup source for drinking water supplies for Miami-Dade, Broward and Palm Beach counties. (Miami-Dade sucks up most of its drinking water from an underground aquifer - the Biscayne Aquifer)

In July 2007 the water level fell below 9 feet, causing a major alarm. Severe water-use restrictions from Orlando to Key West were put in place. The lake level had been recovering slowly this year, but was still well below average. While we have had plenty of rain in south Florida, central Florida hasn't been getting enough - until now.

The rising water level is hardly the end of Lake Okeechobee's problems. Pollution, and restoration of the eco-system, still present big challenges for the future health of the lake.

- David Adams