Cold north winds followed by stout winds from the tropical south
SFL Weekly Watersheds Summary: Feb 5-11
WEATHER. As is typical in the south Florida winter, the coldest of cold fronts can be fairly rapidly followed by an equally stout wind from the tropical south. It’s that interplay of air masses that brings us our winter rain storms. On Superbowl Sunday a fairly heavy dose of that rain (around an inch) fell in Miami, and spread in slightly less plentiful amounts across south Florida. Then a week later this most recent Sunday a similar event spread about a half inch across the southwest coast. We’re still only half way through the dry season, and to date have received right around half our full dry season amount. The picture is even drier when we extend the time horizon back a full 365 days. All major basins have received under 50 inches over the past 365 days. The Lake and Kissimmee are all below 35 inches. Broward County and the Upper Kissimmee have received the most rain over the past 90 days — a little over 10 inches each. All other areas of the district are averaging under 10 inches over the past 3 months, with the Lake O, East Caloosahatchee, and St Lucie basins trailing the list at under 5 inches over the past 3 months each.
BIG CYPRESS. Big Cypress sort of straddled the past two Sunday rainfall events. The preserve has received a combined 1.5 inches of rain so far this February. Preserve-wide water levels have stablized over the past 3 weeks as a result. Its the sort of rain that stablizes water levels in the short run, and in the long run can have the cumulative effect of slowing down the descent of the spring drydown. The preserve is currently at the same level it was in middle of March of last year. That puts current preserve-wide water levels at about 4 inches below our 5-year average for mid February, and about 8 inches below mid February of last year.
EVERGLADES. There was about 200 cfs moving down the L29 canal through the S333 and S334 structures. Otherwise, the gates of the conservation areas are closed. We’re now entering the driest part of the dry season, when the S12s and other structure’s of the conservation area are pretty much flowless for the whole historic flow record. 1998 was the most recent year when S12s flowed over 500 cfs in either March, April, or May. Before that, the S12s flowed in excess of 3000 cfs for most of Spring of 1995. In Spring of 1993, the S12s flowed over 1500 cfs for much of that season. Looking even farther back in time, the S12s flowed in excess of 1000 cfs in Springs of 1983 and 1984. (1983, 1995, and 1998 were all high-signal El Nino years). All those year’s are the expection however. This year the S12s were completed closed by mid December and over the past 5 years the average flow through the S12s has receded to zero by early February.
LAKE O. Lake O stage has dropped to 11.5 ft msl. That places it at about 3.5 ft below the 5-yr mid February average and almost 4 ft below mid February of last year. About 500 cfs are flowing through the S79 WP Franklin structure, presumably to control saltwater intrusion in the lower Caloosahatchee. Lake stage is currently about 8 inches higher than mid February of the drought year of 2001.