M E M O R A N D U M
TO: Chip
Merriam, Deputy Executive Director, Water Resources
FROM: SFWMD
Staff Environmental Advisory Team
DATE: June 24,
2008
SUBJECT: Weekly
Environmental Recommendation for Systems Operations
Recommendation
No
Lake Okeechobee regulatory releases to
the south or estuaries are recommended.
Background
Scattered
showers/storms focused southwest through northwest of the Lake
this afternoon. High pressure is finally
building northward as evident by the easterly winds in the low levels of south Florida soundings. Storms will form inland east and move
westward late morning through this afternoon.
Then, our first interaction with a tropical wave occurs tomorrow. Moisture will increase, especially south, and
favorable upper level winds will help generate an above average rain day. Drier air will follow the wave on Thursday
with below average rainfall expected the end of the week and into the weekend. The next ten days precipitation outlook is below
average with low confidence.
Kissimmee Watershed
Over the last
seven days, the upper Kissimmee Basin received 2.28 inches of rainfall to bring
the 30 day total to 6.07 inches (96% of average), and the lower basin received
2.22 inches to bring the 30 day total to 5.50 inches (89% of average). With the recent rainfall, water levels in
most of the lakes are beginning to rise but all remain below regulation
schedule. Lake Kissimmee remains at 49 feet.
In the upper basin, snail
kites continue to nest on East Lake Toho, Lake
Toho, and Lake Kissimmee. Nests on Lake
Toho continue to represent a large
fraction of the total number of snail kite nests in Florida.
Flow has been
reestablished to the Kissimmee River for 343
days (S-65 re-opened on 07/18/07). Flow
is approximately 200 cfs at S65.
River water
levels within the Kissimmee River Restoration Project area have been rising and
falling in response to rainfall events.
Dissolved oxygen
concentrations in the river channel of the Kissimmee River
remained above thresholds of concern.
Concentrations ranged from 3.6 mg/L to 7.3 mg/L and averaged of 5.3
mg/L.
Lake Okeechobee
According to the USACE web site, Lake Okeechobee
stage is 9.32’ NGVD, which is 0.05’ higher than a
week ago and 0.43’ lower than a month ago.
The current stage is 0.40’ higher than it was a year ago and 4.06’ below
its historical average for this time of year.
Total reported inflows are
approximately 1600-1700 cfs and include 496 cfs from the Kissimmee River,
553 cfs through the S71, 133 cfs
through the S72, 246 cfs from the L8 at Canal Point,
and approximately 200-300 cfs through the S308. No outflows are reported.
Monthly phytoplankton
monitoring was conducted yesterday.
Despite calm conditions, secchi depths were
only 30-50% of total depth. The cause of
these rather low transparencies could not be determined. The water column had a slight greenish hue,
but otherwise there were no signs of bloom formation at any of the sampling
locations.
Muck removal operations are
underway in the littoral zone in the vicinity of Worm Cove and Horse Island. Approximately 130 acres will be scraped
within the next few weeks. A similar
project approximately 50 acres in size should begin in the Harney Pond area
within the next few weeks and be completed by August.
St. Lucie Estuary
There were no releases
through S-80 from C-44 over the past week.
An average discharge of 200 cfs through S-48
from C-23 and 190 cfs through S-49 from C-24 occurred
over the past week. The current weekly
average salinities (in bold) at the four monitoring sites in the St. Lucie are
given below in parts per thousand (ppt), along with
the previous week’s (in parenthesis).
|
Weekly Average Salinity
(ppt)
|
|
Sampling Site
|
Surface
|
Bottom
|
Envelope
|
Palm City Bridge (S. Fork)
|
17.42 (18.05)
|
19.76
(20.77)
|
|
HR1 (N. Fork)
|
17.66 (21.05)
|
22.02 (23.42)
|
|
Roosevelt Bridge
|
21.51 (24.22)
|
23.18 (25.42)
|
8.0 – 25.0
|
A1A Bridge
|
29.48
(29.83)
|
NA (NA)
|
20.0 – 31.0
|
Compared with salinities of
the previous week, average salinity decreased throughout the estuary due to
local runoff. Salinities at HR1 and Roosevelt
Bridge decreased about
2-3 ppt.
Salinity at Palm
City Bridge
decreased 1 ppt.
Salinity decreased only slightly at A1A
Bridge. Salinity conditions in the
estuary are considered fair, based on the salinity preference of the oyster, Crassostrea virginica,
at Roosevelt Bridge.
The current surface salinity of 21.5 ppt at
the Roosevelt Bridge is 6.5 ppt
below the maximum weekly average of 28.0 ppt achieved
in May 2001 during the 2000 – 2001 drought.
Caloosahatchee Estuary
An average weekly discharge
of 334 cfs occurred at S-79. No flow was reported at S-77 except for 98 cfs discharge back to the Lake
on June 22. The concentration of
chlorides at the Olga Plant was 178 ppm yesterday,
down from 228 ppm in the beginning of this reporting
period. Current weekly average salinity (in bold) may be compared to last
week’s data (in parenthesis).
|
Weekly Average Salinity
(ppt)
|
Sampling Site
|
Surface
|
Bottom
|
Franklin Locks (S-79)
|
13.53 (17.84)
|
14.80
(20.06)
|
Rt. 31 Bridge
|
16.80 (18.25)
|
20.10 (22.68)
|
I-75 Bridge
|
17.96 (20.71)
|
20.76
(22.55)
|
Ft. Myers Yacht Basin
|
23.75 (24.67)
|
24.16
(25.67)
|
Cape Coral Bridge
|
28.81 (30.04)
|
29.21
(29.98)
|
Shell Point
|
34.37 (35.08)
|
34.42
(35.22)
|
Average salinities dropped
throughout the estuary, ranging from about 5 ppt at
S-79 to only about 1 ppt at Ft. Myers
to Shell Point. Average salinity at the Ft. Myers
surface sensor was 23.8 ppt, still above the 1-day MFL criterion of 20 ppt. The current surface salinity of 13.5 ppt at S-79 is 6.5 ppt below the
maximum weekly average of 20.0 ppt achieved in May
2001 during the 2000 – 2001 drought. Salinity at Shell Point and the Cape Coral Bridge is above the optimal range for
the oyster, Crassostrea virginica. Salinity conditions in the upper estuary east
of Ft. Myers are still poor due to high
salinity. Conditions in the lower
estuary downstream of Cape Coral
are becoming poor considering the combine salinity preference of oysters and seagrasses.
No Karenia brevis, the
Florida red
tide organism, was detected through June 20th, in water samples
collected alongshore between Pinellas and Collier counties. Discolored water is possible alongshore of Lee County
due to the continued presence of high concentrations of the marine cyanobacterium Trichodesmium.
Trichodesmium can collect at the water surface
and appear brown, green, or white. At
high concentrations, a Trichodesmium bloom may
be mistaken for an oil or sewage spill.
Water Conservation
Areas
The heavy
rainfall this week produced rapid reversals and elevated stages throughout the
Greater Everglades. Stages rose between 0.2 ft in WCA-3B to 0.82 ft in
northeastern Shark River Slough.
Stage reversals produced poor conditions for wading bird foraging
throughout the Everglades, and depths were
also generally poor for foraging except in parts of WCA-2B
and WCA-3B.
With the high rainfall this week, stages in WCA-1
and WCA-2A are above regulation, and are at
regulation in WCA-3A.
Everglades National Park
Substantial rainfall totals
were measured across the southern Everglades last week, including accumulations
of 2.5-7.1” in Everglades National Park (ENP) and Florida Bay.
The basin-wide rainfall was 5.2” in the ENP
basin and 4.7” in the C-111 basin, a welcome increase from weeks past.
In response to this much-needed
rainfall, water levels rose across the ENP
wetlands. Water level increased by a
substantial 3.7” in Shark River Slough at P33, 16” at Taylor Slough Bridge,
9.4” in the panhandle (station EVER6), and 8.2” in
the southern part of Taylor Slough at Craighead Pond. Stage still remains below average for this
time of year at Taylor
Slough Bridge
and Craighead Pond, but this week’s increases improved deficits in Taylor
Slough. As of June 18th,
moderate flows (< 200 cfs) occurred from S332D towards Taylor Slough.
Salinity across Florida Bay remains elevated, but declined
following the heavy rainfall. Concentrations
dropped into the mid-30s across northeast Florida Bay
last week. Salinity in the Taylor ponds
declined considerably from the mid-upper 30’s 2 weeks ago to the lower-mid 20’s
last week These declines will show up in the Taylor
River (TR) 30-day moving average (used for tracking
the FL Bay MFL criterion), but they presently remain
at 34.5 psu (nearly unchanged from last week’s
reading). Salinity also dropped
substantially in the north central Bay areas of McCormick Creek and Terrapin Bay, from the upper-40s in last week’s
report, down to the mid-30’s this past week. The central Bay station in Whipray
Basin recorded salinity
in the mid-40’s for another week, despite receiving 5.6”
of rainfall for the week. Salinity in
the upstream reaches of Shark River (Tarpon
Bay platform) remained
near 12 psu for another week, a bit above average for
this time of year
Water Supply
Although there was some rain
last week, most of the water fell south of Lake Okeechobee. Water levels in the upper and lower Kissimmee Basin are now well below their average
conditions for this time of year, and approaching their historic lows. Water levels in the Lower
West Coast are now below historical averages, although there was
some continued rebound this week. Water
levels in the Lower East Coast are now near
historical averages. Water levels in the
Upper East Coast are still slightly above their
historic averages, although they also have been declining. Surface and groundwater levels in Water
Conservation Areas 1, 2 and 3 are now near their historic averages, most wells
enjoyed a rebound this week. Water
levels in the southernmost portion of Miami-Dade County
are now near their historic average levels and rebounded sharply this week.
There was also some
improvement in the water supply risk indicators since last week. Six out of the eleven water supply risk
indicator parameters are now in the “low” risk category, including the CPC
Precipitation Outlook, the Lake Okeechobee Seasonal and Multi-seasonal Net
Inflow Forecast, and Water Conservation Areas 1, 2A and 3A.
Four out the eleven water
supply risk indicators are now in the “medium” risk category, including Palmer
Index for Tributary Conditions and LEC Service Areas
1, 2 and 3.
Only one risk measure is now
in the “high” risk category, the projected Lake Okeechobee Stage (Water
Shortage Management Band).
LORS2008 (Lake Okeechobee
Regulation Schedule)
The current Lake
Okeechobee stage remains in the Water Shortage Management zone and
is unlikely to move back into the Operational Band in the next several months
during the persistent La Niña climactic conditions.
CC: George Horne