WCA - Everglades Conditions Update (September 4, 2007)

 

 

Rainfall:

Unlike the ENP, rainfall varied very little over the WCA’s, averaging about 0.5” everywhere (see Raindar.gif). In the Park and Fl Bay rainfall was patchy again, falling heaviest over western parts of the system and ranging from 0 – 1.9” over the 7 d period. Raindar spatially averaged basin-wide accumulation was 0.93” for the week in the ENP. Rainfall was not enough to keep up with evaporation (see srs.pdf) across the Everglades Protection Area (EPA) and, as a result, the average water deficit was between 0.5 and 1 inch for the week.

 

Water Conservation Areas:

The EPA gauges indicated stable water stages in WCA-1 and NE Shark River Slough, rising water levels in WCA-2B, and falling water levels in WCA-2A, 3A and 3B. (see WCA stages spreadsheet). At this time of year, falling stages in the Everglades equate to “Poor” hydrologic conditions. If depths continue to drop below 1 ft during the 2007 wet season, then there will be extended dry conditions in the Spring of 2008 which will prevent wading birds from feeding and may cause significant peat fires to erupt. Like last week, stages in WCA-1 are below regulation but still in Zone A2, stages in WCA-2 are at regulation, and stages in WCA-3 are below regulation (see WCA regulation stages).

 

 

Everglades National Park:

Water levels decreased for another week at all ENP platforms. Depths at the Taylor Slough Bridge (TSB) water level plunged by 5.6”, another week of > 5” weekly recession As a result, the TSB stage is 1.5 ft lower than it was this time last year, and 2.5 ft lower than it was this time two years ago (see stage.pdf). In the panhandle region (EVER 6), water level was down by just over 2.25”.  Stage at Craighead Pond (CP) & to the north in Shark River Sl. (P33) dropped by 1.2” & 1.4” over the 7 d period, respectively.  These recession rates are unusual for this time of the year when water levels are typically still increasing.

 

One would think that salinity in the mangrove transition zone would rise with falling stage. However, local rainfall and possibly a long lag time between affects of stage change on salinity, has prevented salinity from increasing last week. The platform at the mouth of Little Madeira Bay saw salinity holding just below 20 psu for another week (see salinity.pdf).  Salinity in the TR ponds remained very low all week (~ 1 psu at Pond 5 & Argyle Hendry).  To the north and west, Tarpon Bay (SRS outlflow) salinity was low, holding near 2 psu for another week.

 

Salinity is holding steady or increasing in the Bay regions of the Park. Salinity readings in the north-central Bay areas of Terrapin Bay and McCormick Creek increased through much of last week, from the mid-20s towards 30 psu by the weekend (likely, in part, to a mid-week Bay water flow reversal).  In the central Bay, Whipray Basin salinity remained near 40 psu for another week. 

 


 

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