WCA - Everglades Conditions Update
(Jan. 15,
2008)
Rainfall:
Rainfall
amounts were between 0.08 (WCA-2A) to 0.271 (WCA-3A) within the WCAs (see Raindar.gif). Rainfall totals were very light
across ENP & Florida
Bay. Most stations
saw only trace amounts (< 0.1), if any, rainfall over the 7 d period.
The exception to this was at P33 in Shark River Slough, where a quick
moving shower dropped close to 0.4 of rain last Monday (1/7), & in Terrapin Bay where just over 0.5 of rain fell
over a 3 hr period on Saturday morning (1/12). The ENP basin spatially-averaged
7 d accumulation of only 0.03 reflects the generally dry trend (see attached
RAINDAR image). With an average pan evaporation
of 0.71, this was another deficit water budget week (see srs.pdf).
Water Conservation Areas:
Overall
GOOD dry-season recession rates continue to dominate the region (see WCA_stages.xls). Northern and central
WCA-3B continues to have FAIR recession rates due to little change over time.
Although recession rates were GOOD, the depths in the Everglades
remain too deep for wading bird foraging. This is normally not an issue at this
time of year because foraging in support of nesting behavior does not usually
begin until February. Only the northern (north of I-75) sections of WCA-3A had
proper depths and recession rates to support wading birds. Stages in
WCA-1 are slightly below Regulation, WCA-3 stages continue to be significantly
below regulation, and WCA-2A remains above regulation (see WCA_reg_stages.doc).
Everglades National
Park:
ENP wetland
water levels continue to decline. Taylor Slough
Bridge saw the most
substantial weekly drop of nearly 1.7, which is not unusual for this station.
All other areas of the Park experienced a weekly decline of approx. 0.5
(areas including Shark River Slough at the P33 gage, the panhandle at the EVER6
gage, & Craighead Pond).
Salinity
concentrations either remained stable or increased slightly in Florida Bay last week. Salinity crept
slowly upwards at the creek sites, into the upper-20s at Trout Ck. and into the
upper teens at the mouth of Taylor
River. Effects from
a flow reversal were evident in the Taylor
River ponds as salinity increased
throughout the week, up to just over 10 psu at Pond 5 and near 8 psu at Argyle
Hendry (station Taylor
River) as of Sunday,
1/13. The 30 d moving average concentration at Taylor River
(used to monitor exceedances to the FL Bay MFL rule) is still low at just over
2 psu. Salinity concentrations at the Little Madeira Bay platform spent much of
last week near 20 psu. In the north-central Bay, salinity increased to 20
psu at McCormick Ck., and to 25 psu at Terrapin Bay.
The platform at Whipray
Basin stopped sending
data after 1/7, so cannot report on trends in the central Bay. In the SRS
outflow at Tarpon
Bay, salinity was near 11
psu as of Sunday 1/13. As of now, the Bay appears to be well buffered in
terms of salinity for the dry season.
Wildlife:
Roseate
Spoonbill: A follow-up on roseate spoonbill nesting status in Florida Bay from
information provided by staff at Audubons Tavernier Science Center (thanks to
Brynne Langan & Jerry Lorenz): An
incorrect statement from last week that few spoonbill chicks have yet hatched;
rather, there are few chicks that have made it to branchling phase (21 d
old). No chicks have reached this stage in the NE Florida Bay colonies at
Deer or S. Nest, where there are a total of 27 nests (note that there are still
no spoonbills nesting at Tern Key, where, on average, there are close to 100
nests). Audubon staff are actively monitoring just over 50 of the 80
nests at Sandy Key, typically the largest colony in northwest Florida Bay.
Seventeen of these monitored nests have branchling phase chicks; eleven of the
53 monitored nests have failed (this # is not particularly high). Overall
the big mystery continues to be the low nesting effort Bay-wide. Audubon
staff are scheduled to visit colonies at Frank & Clive Keys later this
month. It is possible that birds that normally nest in the NE Bay or at
Sandy Key may have moved out to these western islands, it is
unlikely there will be enough to make up for the deficit seen this year at
Tern & Sandy.
System wide
nesting behavior surveys will begin in February. For now, random foraging
observations are qualitative, but important. Approximately two thousand birds
(Spoonbills, Ibis, Egrets and Woodstorks) have been observed foraging in the
very northern and northwest section of WCA-2A. (Note: The topography in
WCA-2A is such that despite depths over 1 ft at the 2-17 gauge, the depths for foraging
can be FAIR to GOOD in the west and NW of WCA-2A).
On January
9th a number of District staff visited the USFWS service office in Vero Beach to discuss the
process of getting WCA-1 and WCA-2A deviations. One crucial metric in
that process is the evaluation of endangered species that my potentially be
utilizing these areas (specifically - Snail Kites and Woodstorks). Wiley
Kitchens (professor/research ecologist at the Florida Cooperative Fish and
Wildlife Research Unit) gave an update on the current status of the Snail
Kite. During the 2001/2002 drought there were approximately 3400 birds
before the drought and these number declined to approximately 1700 post
drought. A 2006/2007 survey shows there are still approximately 1600
snail kites remaining. Wiley suggests that these bird numbers could
potentially be reduced half again during this current drought. Bottom
line is that reproduction rates are very low with few birds making it to
adults. Conclusion is that the Snail Kite population is in peril.
District staff along with others in the ornithology community are trying to
investigate whether there is enough information/data to develop a model that
can help us in our decisions for water operations within the system.
Extensive
fish kills along the northern Bay have been reported by several researchers
following the recent cold snap. Many species, including large tarpon,
snook, goliath grouper, & barracuda were affected by water temperatures
that reportedly dropped to 4oC in some of the coastal embayments.
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