MEMORANDUM
TO: Chip
Merriam, Deputy Executive Director, Water Resources
FROM: SFWMD Staff Environmental Advisory Team
DATE: January 29, 2008
SUBJECT: Weekly
Environmental Recommendation for Systems Operations
Recommendation
No Lake Okeechobee regulatory releases to the
south or estuaries are recommended.
Background
Mainly warm and dry this
week. Deep layered high pressure
dominates from the southern Gulf of Mexico through the Florida peninsula and up the Atlantic
coast. Elsewhere, a very active and
progressive pattern exists over most of the US.
This general pattern should hold into next week, thereby allowing only
the tail ends of weakening fronts to periodically drop into the peninsula
before retreating northward. This is not
a favorable scenario for any significant rainfall, though some garbage showers
should dampen a few lawns. Next hope for
significant rain is not obvious, but a front could push through in about 10
days. The next
ten days precipitation outlook is below average with moderate confidence.
Kissimmee Watershed
Over the last 7 days, the upper Kissimmee Basin
received 1.15 inches of rainfall to bring the 30-day total to 3.08 inches,
which was 132% of the long term average, and the lower basin received 0.26
inches to bring the 30-day total to 1.30 inches, which was 72% of average. Continued rainfall caused water levels in the
upper basin lakes to rise slightly (0.1-0.3 feet). Water levels in the upper basin lakes remain
below regulation schedules except for Lake Toho,
which is slightly above regulation schedule.
Lake Kissimmee (S-65) continued discharging approximately
250 cfs to the Kissimmee River. Releases from Lake Toho
(S-61) began last week and have been increased to 700 cfs. No other releases are being made in the upper
basin. Flow has been reestablished to
the Kissimmee River for 188 days (S-65
re-opened on 07/18/07).
An update on dissolved oxygen concentrations in the river channel
of the Kissimmee River is not available this
week because of maintenance issues.
Anecdotal
observations from last week included numbers of birds (wading, shore, and
water) using the floodplain (Oak Creek
marsh) within the Phase I area of the Kissimmee River Restoration Project. Roseate spoonbills were also reported using
the same marsh.
Lake Okeechobee
According
to the USACE web site, Lake
Okeechobee stage is 10.06’ NGVD, which
is 0.05’ lower than a week ago and 0.22’ lower than a month ago. The current stage is 1.66’ lower than it was
a year ago and 4.68’ below its historical average for this time of year. Inflows from the Kissimmee River (S65E) continue at approximately 250 cfs. No major outflows are reported.
Monthly
phytoplankton monitoring was performed on January 23rd. Six of the 9 monitoring stations had
sufficient water to sample and no algal blooms were observed at any of these
stations. Average secchi
depth declined to 0.29 m from 0.40 m in December, and average SD:TD declined to 0.23 from 0.30
in December. A SD:TD ratio < 0.5 generally is not conducive to SAV growth. These
light conditions are normal for this time of year.
St. Lucie Estuary
There
were no releases through S-80 from Lake Okeechobee
or the C-44 Basin. There was no
discharge from S-49 on the C-24 Canal during the last week and average flow for
the week from C-23 through S-97 was < 1.0 cfs. 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)
|
11.2 (11.1)
|
14.2 (13.5)
|
|
HR1 (N. Fork)
|
16.5 (15.4)
|
18.27 (16.8)
|
|
Roosevelt Bridge
|
19.2 (18.7)
|
20.2 (19.7)
|
8.0 – 25.0
|
A1A Bridge
|
27.3 (27.6)
|
28.7 (28.9)
|
20.0 – 31.0
|
Except
at the A1A Bridge, average salinity increased
slightly during the past week. Both the surface and bottom salinity are in the
preferred range at the Roosevelt
Bridge, and at the A1A Bridge. The
current surface salinity of 19.2 ppt at the Roosevelt Bridge is 8.8 ppt
below the maximum weekly average of 28.0 ppt achieved
in May 2001 during the 2000 – 2001 drought (last
week’s difference was 9.3 ppt). Based on the salinity
tolerances of the oyster, Crassostrea virginica, salinity conditions in the estuary are good.
FWRI reports no Karenia brevis, the Florida
red tide organism, in samples collected between Volusia and St. Lucie counties.
Caloosahatchee Estuary
Discharge
for the week at S-79 averaged 367 cfs as a result of
3 days of flow with a peak of 966 cfs. The 30-day average discharge from S-79 is 86 cfs. The
concentration of chlorides at the Olga Plant is 184 mg/l. Weekly average salinities for specific sites
are given below in parts per thousand (ppt). Current weekly averages (in bold) may be
compared to last week’s data (in parenthesis).
|
Weekly Average Salinity (ppt)
|
Sampling Site
|
Surface
|
Bottom
|
Franklin Locks (S-79)
|
16.9 (18.5)
|
17.8 (18.7)
|
Rt.
31 Bridge
|
17.7 (17.7)
|
19.5 (18.4)
|
I-75
Bridge
|
NA
|
20.5 (20.5)
|
Ft. Myers
Yacht Basin
|
23.6 (22.7)
|
23.6 (22.9)
|
Cape Coral Bridge
|
25.3 (25.9)
|
30.3 (29.1)
|
Shell
Point
|
33.8 (32.8)
|
35.3 (34.5)
|
Salinity
declined only at the S-79 downstream recorder as a result of the S-79 releases.
The salinity at all the other recorders located downstream of S-79 (except the Cape Coral surface
sensor) either remained unchanged or salinity increased slightly. The current surface salinity of 16.9 ppt at S-79 is 3.5 ppt below the
maximum weekly average of 20.0 ppt achieved in May
2001 during the 2000 – 2001 drought. Salinity at the Ft. Myers
surface sensor remains above the 1-day MFL target (20
ppt). Salinity
at the Cape Coral
Bridge surface recorder
is at the upper limit of the optimal range for the oyster, Crassostrea
virginica.
Salinity at the bottom sensor exceeds the preferred range. Salinity at Shell Point is either near or is
beginning to exceed the tolerance limits of oysters. Salinity downstream of Cape Coral is good for seagrass.
Based
on submerged plants requirements, conditions in the upper estuary, east of Ft. Myers,
are poor due to high salinity. Based on
the salinity tolerances of oysters, salinity conditions in the estuary
downstream of the Cape Coral
Bridge is fair.
FWRI reports that water samples collected along the shore between Pasco and Collier counties contained no Karenia brevis, the
Florida red
tide organism. Samples off shore had either no organisms or concentrations at
background levels.
Water Conservation Areas
Good dry-season recession rates continue
to dominate the region. Like last week,
only two regions had poor recession rates due to slight increases or no
change. They were the northern regions
of WCA-1 and WCA-3B. This should not set off any alarms and
desires to reduce WCA-1 or WCA-3B
water levels at this time because water levels are below average for this time
of year and water conservation is needed.
Stages in WCA-1 are slightly below Regulation,
WCA-2A remains above regulation, WCA-3
stages continue to be significantly below regulation, and there has been little
change since last week.
Everglades National
Park
Everglades
National Park (ENP) wetland water levels showed mixed
trends last week. Water level at Taylor Slough
Bridge remained unchanged
from last week. There was an increase in
water levels in Shark River Slough (station P33, up by 0.4”) and in the
panhandle (station EVER6, up by nearly 1” from last
week as a result of high rainfall totals).
In South Taylor Slough, Craighead Pond water level declined by 0.6” over
the 7 day period.
Salinity
concentrations increased slightly or remained stable in Florida Bay
last week. Salinity held in the
lower-20s at Trout Creek and in the mid-upper teens at the mouth of Taylor River. The 30 day moving average concentration at
Taylor River (used for to monitor exceedances to the
FL Bay MFL rule) is still low (4 psu),
which is good, but should be monitored closely due to the rate that it has been
increasing over recent weeks. The
platform at Whipray
Basin is again
transmitting data, and recorded salinity near 30 psu over much of last week.
As a whole these salinity concentrations are near seasonal norms.
The
exception to this trend is out west, in the Shark River Slough (SRS) outflow at
Tarpon Bay, where salinity remains above its
seasonal average, measuring 13.5 psu as of Sunday
1/27; this is not surprising given the low water levels in SRS.
Water Supply
Water
levels in the upper and lower Kissimmee
Basin and Lower
West Coast increased on average this week, but remain below their
historical average conditions for this time of year. Water levels in the Lower
East Coast are still slightly above their historical averages, and
most wells recorded modest increases in water levels due to local rainfall. Water levels in the Upper
East Coast continue to remain above their historic averages. Surface and groundwater levels in Water
Conservation Areas 1 and 2 are now near or slightly below their historic
averages. Water levels in WCA 3A continue to remain below their historic averages and
were somewhat lower this week. Water
levels in the southern-most portion of Miami-Dade County
are now below average historic conditions.
Seven
out of eleven water supply risk measures are in the “high” risk category: the projected Lake Okeechobee Stage (SSM), the Palmer Index for tributary conditions, the CPC precipitation
outlook, the Lake Okeechobee seasonal net inflow
forecast and Lower East Coast Service Areas 1, 2 and 3. Water Conservation Areas 1, 2A and 3A
continue to be in the “low” risk category and the Lake
Okeechobee multi-seasonal net inflow forecasts remain at “medium”
risk this week.
Chlorides
at the Olga water treatment plant on the Caloosahatchee River
are now at 184 ppm and the plant is operational.
WSE
(Lake Okeechobee Regulation Schedule)
The
current Lake Okeechobee stage remains in the
Water Shortage Management zone and is unlikely to move back into Zone E in the
next several months during the persistent La Niña climactic conditions.
CC: George
Horne