Wet season peak

Loxahatchee levels jump, water structures open

Week of October 1 – 7

Recent photos taken along Cypress Bend Boardwalk
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RAINFALL UPDATE
The Kissimmee River received around 2.5 inches of rain last week, and the Lake received just under 2 inches of direct rainfall. Water Conservation Areas 1 and 2 also received around 2 inches of rain last week, which was icing on the cake for the 9 inches its received over the past 3 consecutive weeks. Miami-Dade leads all other basins with 11.5 inches over the past 3 weeks.
The southwest coast (from Naples to Miami) has only received 5 inches over the same 3-week period. If you’ll remember it was only a couple of weeks ago in the heart of September that we were commenting how all the rain was falling in Florida’s southwest corner. Its been all East Coast ever since we pointed that out. There must be a meteorological term for the tendency of weather patterns to shift as soon as you point out a trend.
What we are seeing is the last sighs of the Summer Rainy Season. Last year the Summer Rainy Season officially ended in the first half of October — I think it was October 6th. That meteorological “line in the sand” more or less occurs in tune with drop of the dew point (night-time low air temperature) below 70° F.
By that metric, we could still have a week or two Rainy Season in Naples. Night-time lows in Naples recently rose back above 75° F over the past week. (Naples Temperature) Last year this time Naples night-time temperatures were touching down into the low 70s.
And don’t forget that the tropical storm season marches on a few weeks after the Summer Rain Machine mothballs its operation for the winter. Case in point are Wilma in 2005 and Mitch in 1998 — both storms ended the Wet Seasons with big exclamation points weeks after the Summer Rain Machine had shut down.
Currently, we still have the last half of October to add to this year’s Wet Season total. October’s long-term average (3-4 inches) is less than half of our core Summer months (8-10 inches).
Below is a historical comparison where this year’s rainy half of the year (May 1 to Oct 31) places relative to year’s past — for the Southwest Coast (Naples and Ft Myers), Miami-Dade, and Lake Okeechobee. The Lake and Southwest Coast are both down for the year, whereas Miami-Dade, with its 13-inch June and recent surge, is having an above average Wet Season.



WATERSHED UPDATE

Early October is when our watersheds traditionally peak, and after which we generally see water levels start their decline into the winter and spring Dry Season.
One of this week’s big stories is that the S10, S11, and S12 gates were either openned, or openned wider, as a result of last week’s rain. As of Sunday, around 200 cfs was flowing through the S12s into Everglades National Park, 1500 cfs was flowing through the S11s into Water Conservation Area 3A, and around 900 cfs were flowing out of Loxahatchee into Water Conservation Area 2. The S5A Pump and the S6P at the perimeter of Loxahatchee have both been averaging around a 2000 cfs discharge rate for the past couple of weeks.

Up farther in the Lake, inflows from the Kissimmee averaged around 650 cfs for the week. Reverse flows from S77 (Moore Haven), S308 (Port Myacca), and L8 Canal Point continue to backflow into the Lake at a combined rate of twice the Kissimmee inflow rate.

The other big news item is that Lake Okeechobee stage rose above 10 ft mean sea level. That’s a major milestone considering the Lake spent almost a half year (5.5 months) below the 10 ft level. Still, its current 10.10 ft level makes it the lowest October level in the history books. You have to go back in time to October 1956 when Lake O entered into October below 11 ft msl, let along below this year’s 10. Lake stage rose above 12 ft msl by the end of October 1956.

The Lake is currently tracking around 3 ft below last year’s early October stage, and 6 ft below the 5-year early October average. Early October is the time of year that Lake stage typically annual peak, which over the past 5 years has averaged around 16 ft msl. Interestingly, in 1998 the Lake stage peaked in March at above 18 ft msl. That anamoly followed the winter of the El Nino of the Century, and matched a similar condition in 1983 when Lake stage also peaked above 18 ft msl in February and March of that year. (Lake stage hydrologic calendar)

This week’s report would be remiss without mentioning Loxahatchee. Its received over 9 inches of rain over the past 21 days. Current water stage in Loxahatchee is 17.5 ft msl (that’s over 7 ft higher than the upstream Lake O), and is over a half foot higher than its 5-yr early October level. Stage in downstream Water Conservation Area 2 is also 4-5 inches higher than its 5-year early October average. Don’t forget that just a couple weeks ago both areas were at or below 5-year summer lows. South Florida watersheds swing from flood to drought stage on annual cycles, and as quickly as a week. Under current conditions, the wetting front in both Loxahatchee and WCA2 has risen up to and above the tree island fringes.

Regulatory stage in downstream Water Conservation Area 3A is down in comparison. Its currently around 1.5 ft lower than the 5-year early October average, and about 1.5 ft below early October of last year. Slough depths in southern 3A are around 2 ft deep. In comparison to other drought years, that’s 0.5 ft below early October of 2000, but still around 0.5 ft higher than Octobers of 1989 and 1990.

Down in the Park, in addition to the 200 cfs flowing through the S12s, structural discharge into Taylor Slough headwaters through the S332s briefly surged to over 1000 cfs following Miami-Dade’s late September 7-inch weekly rainfall, and inflows into the Park’s western arm from Big Cypress National Preserve have risen to a Summer high of around 1500 cfs.

At Shark Valley Tower, wetland stage is about a half foot lower than early October of last year, and 1.4 ft below early October of 2005. Farther east in Shark River Slough, water stage has risen 4 inches over the past 2 weeks, but that leaves us at still about a half foot below the 5-yr early October average.

Big Cypress National Preserve is the goldilocks of this year’s Wet Season finale. Its neither too high (Loxahatchee) or too low (Lake O, 3A, ENP) relative to Octobers of the recent past. Its tracking right along the 5-year early October average. That places the preserve’s wetting front lapping at the shores of our hydric pinelands, and placing over a foot of water in our tall cypress communities.

Hydric pinelands and wet prairie mosaic in central Big Cypress National Preserve. The wetting front in the preserve is currently lapping at the shores of the preserve’s hydric pinelands, and around a quater to half foot deep of water in the preserve’s wet prairies. Deeper marshes and cypress swamp are currently flooded with closer to a foot and half of water.

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