Three week dry summer spell continues
SFL Weekly Watersheds Summary: Aug 7-13

RAINFALL: South Florida summer rain machine has slowed considerably for the past 3 weeks. A front moving down the Florida peninsula is bringing with it a chance of higher rain for this upcoming week, but the last 3 weeks have been dry throughout the KOE watersheds, including southwest Florida.

LAKE O: In mid August of last year over 10,000 cfs and 3,000 cfs, respectively, were dicharging through the S79 (Caloosahatchee) and S80 (St Lucie) structures. This year couldn’t contrast more: there’s been zero lake-derived discharge through the S79 and S80 structures so far this summer. In July S79 flows briefly peaked just above 2000 cfs and S80 flows peaked at 500 cfs, but all of this water was from local-watershed rainfall; and not from the lake. The reason for such low discharges so far this summer is that lake stage is so low (12 ft above sea level as of Sunday) and rainfall in the upstream Kissimmee Basin, which flows into the lake through the S65E structure, have been well below normal. Looking back at recent history, discharge through the S65E remained above 1000 cfs for a 12-month period from March 2005 to March 2006 (peaking >5000 cfs in July and November 2005), but since March of 2006 (for the last 5 months) lake inflows from the S65E structure haven’t topped 1000 cfs. So its been a dry run. The outcome is that lake stage is not high enough to warrant regulatory discharges. The spector of drought has recently entered into the discussion with respect to Lake forecasting, but we still have a good chunk of the summer rainy season left so conditions could change. Lake stage is currently 1.5 ft below the bottom of the littoral zone, 2.5 ft below the 5-yr average for mid August, and 4 ft below mid-August of last year.

WATER CONSERVATION AREAS: Ths summer rise of surface water in the Conservation Areas has slowed. Stage has dropped about 0.75 ft in WCA2 over the past 3 weeks, whereas stage in Areas 1 and 3 have more or less plateaued off. Stage in all three areas are currently 1.0-1.5 ft below their 5-yr average high water mark, which typically occurs at the end of the rainy season in September. Stage is flooding up to the slough landscape type in in WCA2A, up to the ridge landscape type in Areas 1 and northern WCA3A, and all the way up to the bayhead and tree island landscape in southern 3A. Structural flows between the areas have also dropped off. Currently, flows through the S10s, S11s, and S12s are 0 cfs, 1500 cfs, and 500 cfs.

EVERGLADES AND BIG CYPRESS. The summer rise of surface water in the Park and Preserve have also stalled in August due to a lack of rain. Surface water in both areas have dropped about 0.5 ft over the past 3 weeks. Surface stage is Shark River Slough is currently at the slough/ridge level, and in the preserve surface water stage has dropped well into the prairie landscape type, which means that most of your hydric and mesic pinelands are high and dry. The S12A structure remains closed, but the S12B, C, and D are openned and currently releasing about 500 cfs into the Park. A recent history of the openning of the S12A is as follows: it openned for the summer in early July in 1999, October in 2000, August in 2001, early July in 2002, late July in 2003, September in 2004, and late June in 2005. So last year was an early summer openning for the S12A. This year’s turning out to be a later openning for the S12A, but not too unusual based on its recent history.

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