Rain from Ernesto boost KOE water levels and flows
SFL Weekly Watersheds Summary: Aug 27 – Sep 3

BIG CYPRESS NATIONAL PRESERVE. Ernesto capped off a very wet August for southwest Florida (>10 inches). Big Cypress National Preserve received about 11 inches for the month, and received +5 inches during the week that brought both Ernesto and a trailing trough of low-pressure that fueled more rain activity in the days after Ernesto passed through. Despite a slow start to this year’s rainy season, both July and August have registered +10 inches of rain for the preserve, so the swamps have filled up and flows under the trail have rebounded. Preserve-wide stage has jumped about an inch above the 5-year average for the start of September, and is currently at the same level as the start of last September. This puts water levels throughout most of the preserve up above the hydric flatwood habitat and lapping at the shores of our mesic flatwoods. Keep in mind that last year “September levels” prevailed from late June to mid November — an unusually long duration at such a high level –, whereas this year’s rise into “September levels” more closely matches our 5-yr trend line. (The 5-yr trend line shows preserve-wide water levels peaking in late September, followed by the slow and steady recession of water levels through the fall and winter.) Flows across the Tamiami Trail are tracking very close to the 5-year average for early September, at around 2000 cfs, with total flows across the trail from Krome Avenue to SR29 at only around 3000 cfs. This means that Everglades National Park is currently receiving around 2/3rds of its northern boundary flow from its headwater preserve (BCNP). Look for the S12s to pick up the pace now that they’ve openned them to full capacity.

LAKE O. Almost 4 inches of rain fell directly on Lake O and in the Lake Istokpoga watershed last week. Lake stage rose over a half foot in response, and as of yesterday is now over 13 ft msl. Lake stage is still low: its 2 ft below the 5-yr average for early September, and 2.5 ft below where it was in early September of 2005. Still, despite the rain, there were only neglible structural outflows directly from the lake. However, the picture between Caloosatchee and St Lucie flows couldn’t be more different. Flows through the S79 WP Franklin dam spiked to over 15,000 cfs, not from the lake, but rather from the drenching in its local watershed. This flow rate is +10,000 cfs higher than the 5-yr average S79 flow for early September. That’s a big departure from the average considering the last few years have seen some pretty high flows. This could be a transient pulse that declines in the upcoming days since its not lake-related. Over on the other side of the coast the S80 didn’t show any flows for the week, presumably due to insufficient rain in that local watershed to warrant openning the gate. As of yesterday, inflows from the Kissimmee spiked to +3,000 cfs as a result of last weeks rain.

WATER CONSERVATION AREAS. Flows in the Conservation Areas increased dramatically from last weeks rain as well. As of Sunday the S10s were flowing at +6,000 cfs and the S11s were flowing at +3,000 cfs, over twice as much as the 5-yr average for early September. As of Sunday the S12s were only flowing at about 500 cfs, which is about 1,500 cfs below the 5-yr average S12 flow rate for early September, but look for this to change next week since all the S12s have now been openned to full capacity. Other inflows to on the upstream end (and northwest end) of Area 3A also increased significantly from last weeks rain, including the S190, S8, and S140.


(1) Rainfall graphs. I’ve updated the watershed summeries to more clearly depict rainfall. What I’ve done is moved the “weekly rainfall” graphs to the “top” of each watershed summary (since rain falls from the sky, it makes more intuitive sense to put rain on the top of the page), re-shaped this dataset in the form of raindrops (also making it more intuitive to mentally digest), color coded it in 1-inch increments (anything over 4 inches for the week is shown as a black rain drop), and variable-sized the raindrops to show the magnitude of rain for the week (which makes it easier to quickly see patterns of successive rainy or dry weeks). Anyhow, I hope its an improvement. You’ll have to take a look and judge for yourself.

(2) Major Structural Flows. I’ve updated the Lake O, WCA3A, and Big Cypress watershed summaries to show 5-yr average flows for the most prominent structures in each respective area. For example, for Lake O the inflow and outflow graphs now include the 5-yr average discharge line for the S65E, S79, and S80. For WCA3A watershed summary the inflow and outflow graphs now include the 5-yr average discharge line for the S11s and S12s. For the Big Cypress watershed summary flows under US41 are also shown relative to the 5-yr average flow line. The advantage to this is that now at a glance you can quickly see where the current weeks discharge compares to the 5-year average without digging too deeply into the data. The lines are difficult to see, since I coded them as thin dotted white lines, but that was the best way I could figure to get the information on the page without visually cluttering up the rest of the page.

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