Myakka Mayaca

Land of the many Gum Sloughs
Rain or Shine Report for March 18
I was up at a conference in Gainesville among other water breathren when I overheard a discussion about Gum Slough.

Thinking that they were talking about Big Cypress National Preserve’s Gum Slough, an enigmatically-narrow marshy flowway south of Tamiami Trail, I eagerly jumped into the conversation to find out more.
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Turns out they were talking about a Gum Slough in central Florida — in Sumter County — upstream of Withlacoochee State Forest, near Bushnell.
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Those backroads traverse some of the most buccolic contry in the lower 48! And that isn’t the only “other” Gum Slough. There’s also one in Suwannee County, and probably a handful of others. Gum Slough may in fact be the “Smiths” of water way monikers in Florida.

Something similar can be said for Myakka … or Myaca … depending at which Myakka/Myaca you are at. Above is a photograph of Myakka River taken at Myakka River State Park. Below is a photo of south Florida’s other Myaca (phonetically identical, but spelled differently) — Port Mayaca at St Lucie Canal’s Lake Okeechobee headwaters.

The US Geological Survey has been monitoring Myakka River flow since the late 1930s, back during the FDR presidency.

Below is a simplified data dump of that historical record, showing dividing flows into 3 generalized categories: below 10 cfs, between 10-500, and greater than 500 cfs. Note that the last time the river exceeded 500 cfs was in September 2006, in the wake of Ernesto, and last spring it dropped down below 10 cfs for 4 consecutive months. That hasn’t happened yet so far this spring.
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In comparison, flows into the St Lucie through Port Mayaca (S-308) have been quiet for the past 2 years, and have practically been non-existent for the past 10 months, other than reverse flows from the St Lucie into the Lake (due low Lake stage). The graph only depicts releases from the Lake into the St Lucie; I’ll have to figure out a way to include those reverse flows.

Lake Okeechobee continues its 6-month long balancing act at 10 ft. At 10.2 ft above sea level, current Lake stage remains at the same approximate level it was back in mid October.

Interestingly, Lake stage has made up ground on last year’s level by staying steady. Current Lake stage is only a few inches below last year’s mid March Lake stage.
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That’s big news considering that 7 months ago in September (2007), Lake stage was still languishing at 9.5 ft and a full 4 feet below mid September of the previous year (2006).

Hydrology is not unsimilar to sports in that regard. Forecasts are made and prognosticators predict, but it ultimately boils down to what happens on game day; or in hydrological terms: as the water cycle turns. South Florida’s water cycle is the show that never ends, and never ceases to surprise.

Many thanks to South Florida Water Management District, the Army Corps of Engineers, US Geological Survey, Fish and Wildlife Service, National Park Service, and all other agencies and individuals within who help keep the water cycle at our fingertips; it’s really amazing what they do.

Here’s a quick summary of conditions in other areas.

There’s lots of flow up in the Kissimmee Basin, or at least relative to other areas. These are typical seasonal releases, but are being strategically timed to benefit snail kite nesting season in Lake Kissimmee and the two Tohos. Over 1,000 cfs is being released through some gates in the upper basin, including the S65 out of Lake Kissimmee.

Loxahatchee and downstream Water Conservation Area 2 are both tracking at 5-year highs for mid March. WCA2 regulatory stage is over a foot higher than mid March of last year, and Loxahatchee regulatory stage is around 9 inches higher than mid March of last year. The on-again-off-again S10s are flowing again. Flows through the S11s into downstream WCA3 increased to over 1000 cfs. It was a month ago that flows through the S11s briefly spiked above 3,000 cfs following the mid February deluge.

Regulatory water stage in Water Conservation Area 3 is tracking along the 5-year average for mid March. Incredibly it’s currently around 0.5 ft above last year’s mid March level.
The reason I say that is that if you turn the clock back a little over a half year, back to September 2007, regulatory stage in 3A was a full 2 feet lower than September of the previous year (2006).
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What happened? February’s 4 inches did the trick.

February’s rain was most abundant in Big Cypress National Preserve. It caused preserve-wide stage to rebound 1.5 feet, rewinding the preserve’s water cycle clock 3 months to November 2007 levels. A month has passed since that jump, and water levels have receded about a third of that total jump. Water levels are now vanishing from the wet prairies and retreating back into the forested cover of the cypress domes and strands.

Keep in mind that unlike the Big Lake, in which waters drop more or less uniformly throughout its full extent, the preserve’s wetland mosaic does not beat to one drummer, but rises and falls in response to localized rainfall and physiography.

Case in point is Deep Lake Strand. It’s the next major strand system to the East of neighboring giant Fakahatchee Strand.

I was out there the other day hunting for water. The wet prairie in transit to it was mostly dry. Thin puddles in some of the marshy swales made it a muddy walk, but mostly of it was dry marl dirt. Even the cypress domes I walked through were dry.

But deep in the heart of Deep Lake Strand I found my water. The central thalwegs of the cypress strands are typically discontinuous, and this one is no different. Back in the Summer wet season it was bustling with moving water: one of the main arteries of surface water flow transporting sheetflow across the landscape towards downstream 10000 Islands.
That’s a far cry from its current status as a stagnant pool of low water refugia.
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And that’s the sign of the wheels of the water cycle as they keep on turning.

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