Out of the aquifer

Rainy start to first half of June
SFL Weekly Watersheds Summary: June 4 – 10

JUNE RAIN. District-wide, 4 inches of rain has already fallen so far this June. That makes June the rainiest month over the past 8 months, when 6 inches fell in September 2006. Last June, 6 inches of rain fell District-wide, and the year before a whopping 15 inches fell District-wide in June. On average, June is the rainiest month of the year for south Florida, averaging 8.5 inches of rain over the past 10 years. Along with June — July, August, and September form the 4 core months of the rainy season — during which around 8 inches of rain falls each month. These 4 core months of the rainy season are bookended at the front and back by the months of May and October, both of which average around 3.5 inches District-wide; but rain or sun during which can play a pivotal role in either boosting or repressing summer-fall season water levels and duration. On the flip side of the coin is the 6 winter-spring months (Nov-Apr) that form our dry season. Rain totals for those months average around 2 inches per month.

In a nutshell, June is a critical month — especially coming out of a drought — not only because its the first core month of the rainy season, but also because its also generally the rainiest. All eyes have been on June, and to date the rain gages are filling up at a nice pace.

BIG CYPRESS. Preserve-wide, the surface-water wetting front rose out of the top of the aquifer right at the start of June, and now the wetting front has risen out of our swamp forest and marsh habitats into tall cypress habitat. Preserve-wide, surface water stage is still about 5 inches below wet prairie and dwarf cypress levels. Spatially, the north part of the preserve — especially north of I75 — remains our driest; whereas surface water is flooding wet prairies south of US41. Historically speaking, June is our dry-to-wet season transition month: on average preserve-wide stage rises over 2 ft from the end of May to the start of July — first rising out of the aquifer, then flooding our swamp forest and marshes, and finally rising into the tall cypress. By the start of July the wetting front usually creeps up into our wet prairies. Currently, preserve-wide stage is about half way up that ladder, and climbing at a pace which is in tune with our 10-year mid-June average. The preserve has received around 5 inches of rain so far this June, which is also half-way up the ladder to Big Cypress NP’s 10-inch June rainfall average.

EVERGLADES. Regulatory stage in 3A has rebounded about 9 inches since the end of May. Currently, regulatory stage is at about the same level of mid June of last year, and about a half-foot lower than the 5-year mid June average. It looks like slough water depths in southern 3A bottomed out at a 1-ft depth. In comparison, during the previous severe drought year of 2001, slough water depths in southern 3A dropped under a 1-ft depth for over a month, and briefly dropped below a half-foot of water depth. Going back even further, the last time that sloughs in southern 3A went completely dry was for a 2-month span between May and July of 1989. Spatially, in comparison to the current 1 ft water depth in southern 3A, sloughs in the Park’s NE Shark River slough (at SRS2) have been dry since mid April and sloughs north of I75 proximate to Site 64 has been dry for 3 months now (since mid March). Current water depths in Loxahatchee’s central slough area are around 9 inches deep.

LAKE O. The Upper Kissimmee Basin has received 4 inches of rain in June so far (thanks to TS Barry). That’s about twice as much rain that has fallen on the Lower Kissimmee and the Lake. But the Kissimmee is still not flowing. Its been 9 months now that the Kissimmee has not been flowing into the Lake. Even then, that most recent spurt of flows from the Kissimmee only lasted for about a month-long period (in September of 2006). The Kissimmee has not flowed consisently for a multi-month duration since its 20-month free flow of 500 cfs or above from August 2004 to April 2006, (during which Kissimmee flows peaked above 10,000 cfs for the months of Sep and Oct 04, Jul 05, and Nov 05). The Kissimmee’s mid-June flow average over the past 5 years is around 2,000 cfs. Suffice it to say that flows from the Kissimmee are down.

Lake stage is currently hovering just below 9 ft msl. Several weeks ago water managers had speculated that the Lake could bottom out below 8 ft msl before in the summer-rain rebound kicked in, but the onset of early rains seems to have at least momentarily stablized Lake stage. In a similar fashion, Lake stage hovered right around 9 ft msl for several weeks in June 2001 before finally rebounding above 10 ft msl in the end of July of that year.

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