WCA - Everglades Conditions Update – 14 April 2009

 

Rainfall:

Rainfall was negligible again in the Greater Everglades (see Raindar image and below).  Basin totals last week ranged up to 0.04” (in WCA-3B):

 

Rain:                            WCA-1:         0.00 in            WCA-3A:        <0.01 in

                                    WCA-2A:       0.00 in            WCA-3B:          0.04 in

                                    WCA-2B:       0.00 in             ENP:                 0.01 in

 

Water Conservation Areas:

Regional pan evaporation of 1.93” (see srs pdf) drove continuing large stage decreases throughout the Greater Everglades.  Water levels are falling at rates considered Fair or Good throughout the WCAs (see WCA Stages spreadsheet), but are particularly high in WCA-2A and Northeast Shark River Slough, -0.24 and -0.31 ft, respectively:

 

Stage Change:             WCA-1:          -0.16 ft             WCA-3A:        - 0.19 ft

                                    WCA-2A:       -0.24 ft             WCA-3B:         - 0.19 ft

                                    WCA-2B:       -0.19 ft              NESRS:           - 0.31 ft

 

All WCAs are far below their regulation schedules.  WCA-1 is about -0.5 ft below, WCA-2A canal stage (used from February to May) has fallen again to about -0.9 ft below, and the WCA-3A marsh is about -0.6 ft below the bottom of Zone E1 (see Reg schedule).

 

Water depths are largely below ground in much of the Greater Everglades (see attached map).  Except for coastal areas, Everglades National Park is dry, with soil water depths well below -1 ft in most of the Park.  Similarly, Big Cypress Preserve water tables are -2 ft or more below ground level.  Surface water remains only in WCA-1, WCA-2B, WCA-3A, and WCA-3B.  Subsurface water depths continue to drop in the WCA-2A and -3A, Holeyland, and Rotenberger.  These water depths increase loss of peat through decomposition and provide higher possibilities of muck fires.

 

Most of the Greater Everglades have moved into the Moderate muck fire risk category (see muck fire risk map) except for the wetter areas described above and along the coastal regions of ENP.   The map shows a high risk of muck fires in far northern WCA-3A, portions of WCA-2A, along Miami Canal in Rotenberger and Holeyland, as well as locally within ENP. 

 

Wading bird feeding conditions remain surprisingly good in most of WCA-1 and middle WCA-3A and -3B (see Recession Rates map).  The southwestern coastal areas of ENP are also showing good recession rates and depths for wading bird feeding, an improvement over last week.

 

Everglades National Park (ENP):

No appreciable rain fell across ENP or Florida Bay last week.  Stations for which we receive data from ENP measured 0” – 0.06” of rainfall over the week, and the basin-wide spatially averaged weekly RAINDAR totals were 0.009” and 0.001” for the ENP and C-111 basins, respectively.

 

Stages (see Stages pdf) continued to drop last week.  Water level in Shark River Slough has dropped by 4.6” since 3/29 (not reported 4/5), and water level at the Taylor Slough Bridge dropped by 5.2” last week.  To the south, water levels in the ENP panhandle and at Craighead Pond dropped by 2.0” and 1.9”, respectively.

 

Salinity (see Salinity pdf) remained steady or increased slightly in Florida Bay last week.  Salinity remained in the mid-30s in the near shore eastern Bay at Long Sound and at the Little Madeira Bay platform, as well as farther into the Bay at Duck Key.  In the north central Bay, salinity in Terrapin Bay and McCormick Creek decreased mid-week into the mid 30s before increasing to 40 psu by week’s end.  At the central Bay platform in Whipray Basin, salinity increased from 40 psu to 43 psu.  In the upstream reaches of Shark River Slough, salinity remained steady at 22 psu. The rate of decline in ENP stages and increase in Bay salinity is higher than average, but is not surprising given the combined effects of low rainfall, high rates of evapotranspiration, and the recent strong southerly winds that drive Bay water northward.

 

The Taylor River platform 30 day moving average salinity increased last week from 24.4 psu (4/5) to 28.0 psu (4/12), and the daily mean salinity remained at 33.0 psu.  It is likely this year will produce a second year exceedance of the Taylor River Minimum Flows and Levels, perhaps as early as next week.  A violation is set as a 30-day running average salinity of 30 psu or above at the Argyle-Hendry station in Taylor River.  The rule, set in early 2006, defines a violation as three consecutive years of exceedances once in ten years, or two sets of two consecutive years of exceedances in a ten year period.  This second consecutive exceedance is not yet a violation of the Florida Bay MFL rule, but involves the period between now and 2018. 

 

Please contact Kevin Cunniff (kcunniff@sfwmd.gov) or Robin Bennett (rbennet@sfwmd.gov) for questions about the ENP/Florida Bay report.

 

Fires:

For another week, no fires were reported by FIRMS (the Fire Information for Resource Management System) in the WCAs or the Park for the week.

 

Wildlife:

Water Conservation Areas:

Large mixed flocks were observed feeding in eastern WCA 1 in close proximity to New Colony 4.  Conditions remain ideal for prey concentration, promoting large foraging flocks in these areas (see map and photo).  The majority of eggs at New Colony 4 have hatched and many chicks (mostly White Ibises and some Great Egrets) were observed crawling through the tree canopy.

 

Please contact James Beerens (jbeerens@sfwmd.gov) with questions.

 

Florida Bay:

Sixteen breeding pairs of roseate spoonbills have attempted second nests, 5 in the northwest Bay and 11 in the south and central Bay.  These areas are not affected by water management, and the south and central Bay colonies do not forage on the mainland.  Overall these are low nest numbers, but first nest efforts earlier this season were also much lower than usually seen across the Bay.  As earlier reported, overall nest numbers were low, but success rates (chicks fledged per nest) were good.  Many of the foraging areas in the southeast Everglades are too dry for the birds to forage.  This is the list of colonies with new nests:

 

Northwestern Bay:

Palm - 5

 

Central Bay:

First Mate - 5

Calusa - 4

 

Southeastern Bay:

Lil' Betsy - 1

 

Southwestern Bay:

South Twin – 1

 

Please contact Robin Bennett (rbennet@sfwmd.gov) for questions about the spoonbill nesting report.

 

 


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