Water levels crest in the Everglades.
SFL Weekly Watersheds Summary: Sep 25 – Oct 1

This is the time of year when water levels typically crest in the Everglades … and this year appears to be following that long-term trend. Wetland water stage rose as much as 1-2 ft in the weeks following Ernesto, and have generally tracked at “September levels” for most September, but now at the start of October, with rainfall having dropped off over the past 2-3 weeks, water levels in most areas have crested and are dropping down. Look for this slow recession of water levels to continue in the upcoming weeks unless we receive more rainfall from the tropics or a front. A rising El Nino in the equatorial Pacific may also come into play. Its a wait-and-see game as usual.

Big Cypress NP. Big Cypress received 8 inches of rain in September. That’s 1 inch below its 10-yr 9 inch average for September. Preserve-wide water levels have started to drop below the mesic shoreline into the hydric pinelands. This means that most of the preserve is still covered with surface water, as one would expect in early October; but that one can expect an increasing amount of dry land to emerge as waters recede away from mesic pinelands. Water is currently deepest in the Bear Island Unit, but this area has dropped a few inches since late September. Water depths have slightly risen in the Lostmans Slough and Raccoon Point portion of the preserve, but in general water levels in the rest of the preserve have crested and are heading down.

ENP/WCA3A. Regulatory stage in WCA3A has crested and started to drop down, but water depths in the southern part of 3A continue to deepen as a result of water pooling behind the Tamiami Trail. Structural discharges through the S12s are flowing at around 2,500 cfs, which is very close to the 5-yr S12 flow average for early October and just a notch below the 3,000 cfs mid-October discharge rate that the S12s have averaged over the past 5 years. After a full month of high discharges through the S11s following Ernesto, which exceeded 3,000 cfs for much of the month, the S11s are scheduled to close later this week. Down in the Park, water depths south of the Tamiami Trail are currently about 2 ft lower than water depths north of the Trail in the southern part of 3A.

Lake O. Its been a summer of pretty much no structural discharges from the Lake. Even following all the rain from Ernesto, Lake stage was low enough that the 1.5 ft rise in Lake stage didn’t prompt a need for structural releases. Currently, inflows from the Kissimmee are around 5,000 cfs below the 5-yr average for early October, and discharges through the S79 (to the Caloosahatchee esturary) are also around 5,000 cfs below the 5-yr average for early October. To date, the last time the S79 has discharged this little water through the start of October has been the 2000 and 2001 wet seasons. Also of interest, late wet season rains in 1994, 1995, 1999, 2004, and 2005 created +5,000 cfs flows through November, and even into December, of those years. But Lake stage was higher in those years, thus making Lake operations more susceptible to releases from heavy late season storms events.

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