WCA - Everglades Conditions Update (Oct. 9, 2007)

 

Rainfall:

Seven-day rainfall totals, starting on Oct 2nd were much less than previous weeks (when rainfall was 2-4 inches), and ranged from a high of 1.2 inches in WCA-1 to only 0.63 inches in NE Shark River Slough (see Raindar.gif). [WCA-2A=0.76”; WCA-2B=0.58”; WCA-3A=0.75”; WCA-3B=0.54”] A deficit water budget has occurred almost everywhere since the total weekly evaporation estimate is 1.29 inches (see attached srs.pdf).

 

Water Conservation Areas:

The lack of rain, relative to evaporation, lead to POOR rehydration rates in WCA-3A, 3B, and NE Shark River Slough (see stages.xls). Decreasing water levels at these locations ranged from -0.04 ft/wk to -0.45 ft/wk in central 3A. Increasing water levels occurred in the northern regions and averaged +0.25 ft/wk. Water depths remain good for this time of year because all locations have at least 1.0 ft of water. Stages in WCA-1 are no longer in Zone A2 and are now at Regulation. Stages in WCA-2A are almost 1 ft above regulation and stages in WCA-3 are still below regulation (see reg stages.doc).

 

 

Everglades National Park:

ENP wetland water levels increased as a result of last week’s rain event on Oct 1st. In some areas, though, these water level increases were substantially less than one would expect given the high rainfall totals, suggesting a significant movement of flow downstream (assuming ET has changed little over recent weeks).  Taylor Slough Bridge represented the exception to this trend, increasing by another 8.5” (after last week’s 7” increase) having received just over 3” of rain for the 7 d period (recharge fueled in part by pumping from upstream structures).  A similar amount of precip fell over the week in Shark River Sl. (P33), where water level was up by just over 2.75” (enough to account for some weekly evaporation).  In southern Taylor Slough (CP) & the panhandle (EVER6), increases in stage were relatively lower: 0.5” & 1.7”, respectively.  Last week’s releases from S197 into Manatee Bay could explain this discrepancy in the panhandle stage vs. rain.

 

Due to rainfall and strong discharge moving out of the coastal creeks toward Florida Bay, salinity dropped across much of the system again last week.   In one month’s time salinity has declined by an impressive 7 – 20 psu in the eastern and central Bay, providing an important buffer for the upcoming dry season.  Salinity concentrations at both Trout Creek and Taylor River mouth platforms held at or near single digits throughout the week.  Little Madeira Bay saw declining salinity for the week, into the lower-teens by the weekend.  Salinity in the TR ponds remained very low at between 0 – 1 psu.  In the northcentral Bay areas of Terrapin Bay and McCormick Creek salinity dropped to 11 – 12 psu (this area in particular has experienced significantly declining salinity concentrations over recent weeks).  Whipray Basin saw another week of declining salinity, down to 33 psu by Sunday, 10/7.  In the SRS outflow at Tarpon Bay, salinity declined to ~ 4 psu after last week’s brief flow reversal that increased salinity to 10 psu.

 

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