Mid November update …
SFL Weekly Watersheds Summary: Nov 6 – 12
BIG CYPRESS. Preserve-wide water levels have dropped down about 0.60 ft (7.5 inches) from this year’s September high-water mark. Surface water flows under the Tamiami Trail have dropped from 4,000 cfs to near zero during that time period. This is the time of the year when the south Florida rain machine switch turns “off”, … this year just turned off a little earlier than normal, and with very little October or November rainfall to date, the drop-off in water levels has been fast out of the gate. As a result, for the past several weeks, preserve-wide water levels have been tracking at the 5-year low for this early in the meteorological dry season (early November). In comparison to last year, preserve-wide water levels are currently 0.5 ft lower than they were mid November of last year.
EVERGLADES. The S12s are still flowing through the C and D structures at a combined rate of about 500 cfs. That makes the current combined S12 flow rate about 2000 cfs less than the mid-November 5-year average. The S12A and S12B structures have been closed in preparation for the Cape Sable Seaside Sparrow nesting season. Water is currently pooling about 1.25 ft behind these structures. Farther upstream, water is pooling about 2 ft behind the S11s and over 3.5 ft of water is pooling behind the S10s. The S11c structure was recently reopenned, but only at a low capacity (<200 cfs), presumable to route water from the S7P. Water depths in southern 3A are the lowest they’ve been in November since November of 2000, but they are still the deepest wetland area in the Everglades with a depth of 2.5 ft. Downstream across the Trail in the Park water depths are about a foot shallower at 1.3 ft deep. Park water levels at P33 are tracking at a 5-year low for the middle of November. However, keep in mind that hydroperiod depth and duration at P33 has been greater in the past 10 years than in the decades that preceded it. Historically speaking, this year’s mid-November water depth at P33 would rank middle of the road in comparison to November’s of decades’ past (prior to 1990) when water depths were routinely at or below a 1 ft depth in November. If we look at the high end of the historical spectrum, there have been a handful of Novembers over the past 5 decades wetland water levels at P33 persisted with depths of greater than 2 ft depth, … which would place the wetting front into the Tree Island landscape type for those Novembers. Those Novembers occurred in 1960, 1969, 1983, 1994, 1995, 1999, 2003, and 2005 (with 1995 and 1999 being the highest). Back up in 3A, going north of I75, wetland water depths are also a foot lower than in southern 3A at a 1.5 ft (at Site 63). Water depths in the WCAs 1 and 2 are also in the 1-1.5 ft range, which means that in general the surface water wetting front is starting to drop into the ridge landscape type. LAKE O. Lake stage is currently tracking at 12.5 ft msl. That places lake stage 3 ft below the mid-November 5-yr average, 4 ft below last year’s mid-November stage, and 0.7 ft higher than mid-November of 2000 (the year of the record drought).