MEMORANDUM
TO: Chip
Merriam, Deputy Executive Director, Water Resources
FROM: SFWMD Staff Environmental Advisory Team
DATE: February 19, 2008
SUBJECT: Weekly
Environmental Recommendation for Systems Operations
Recommendation
No Lake Okeechobee regulatory releases to the
south or estuaries are recommended.
Background
Minor
rains south and east today and tomorrow.
A frontal boundary is exiting southward through the Keys this morning
while a batch of mainly light rain slides eastward across south Florida. Look for this rain to exit south and east at
lunch time with little rain expected this afternoon through tomorrow
morning. The front will begin to return
northward as a warm front tomorrow evening as the next upstream weather system
moves into eastern Texas. The warm front should generate some showers
mainly east tomorrow night/predawn Thursday, then a higher coverage of showers
mainly north of the Lake on Thursday. Little or no rain is expected Friday before
showers/storms focus north of the Lake on
Saturday. The next
ten days precipitation outlook is near average with moderate confidence.
Kissimmee Watershed
Over the last seven days, the upper Kissimmee Basin
received approximately 0.4-0.5 inches of rainfall and the lower basin received
1-1.5 inches of rainfall. Water levels in the upper basin lakes are at or below
their regulation schedules.
Lake Kissimmee (S-65) continued discharging approximately
250 cfs to the Kissimmee River. Releases of 300 cfs
are being made from Lake
Toho (S-61). No other releases are being made in the upper
basin. In the upper basin, snail kites are nesting
on East Lake Toho in addition to Lake
Toho.
Flow has been reestablished to the Kissimmee
River for 209 days (S-65 re-opened on 07/18/07). Dissolved oxygen concentrations in the river
channel of the Kissimmee River ranged from 5.1
mg/L to 8.9 mg/L with an average of 7.2 mg/L.
The
USFWS has requested to begin
making releases now from Lake
Toho and East Lake Toho
so that the water levels in these lakes would decrease more gradually to the
low pool stage of the regulation schedule by June 1. Earlier releases and a slower recession rate
are thought to benefit the endangered snail kite during its nesting season. This should also result in lower discharges for
hydrilla treatment in Lake Cypress.
Lake Okeechobee
According
to the USACE web site, Lake
Okeechobee stage is 10.13’ NGVD, which
is 0.15’ higher than a week ago and 0.04’ lower than a month ago. The current stage is 1.18’ lower than it was
a year ago and 4.64’ below its historical average for this time of year. Reported inflows include the Kissimmee
River, the S77, and the L8. No outflows are reported.
The
February submerged-aquatic-vegetation (SAV) survey is
complete. The macroalga
Chara remains the dominant SAV
species and was found at 8 of the 29 sites sampled. This distribution is similar to that reported
in January. Total biomass increased
slightly from 0.21 g dw/m2 in January to 0.46 g dw/m2 in February.
St. Lucie Estuary
There
were no releases through S-80 over the past week. No discharge occurred at S-97 on the C-23
Canal or at S-49 on the C-24 canal. 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)
|
9.7 (12.9)
|
12.7 (15.6)
|
|
HR1 (N. Fork)
|
16.9 (16.4)
|
18.2 (18.7)
|
|
Roosevelt Bridge
|
21.2 (22.0)
|
22.0 (22.5)
|
8.0 – 25.0
|
A1A Bridge
|
27.6 (28.0)
|
28.7 (28.9)
|
20.0 – 31.0
|
Average
salinity decreased by several ppt at the Palm City
Bridge during the past
week but fell only slightly (< 1.0 ppt) at most
other sites. Both the surface and bottom
salinity are in the preferred range at the Roosevelt Bridge,
and at the A1A Bridge. Based on the salinity
tolerances of the oyster, Crassostrea virginica, salinity conditions in the estuary are
good. The current surface salinity of
21.2 ppt at the Roosevelt Bridge
is 6.8 ppt below the maximum weekly average of 28.0 ppt achieved in May 2001 during the 2000 – 2001 drought.
Caloosahatchee Estuary
Owing
to local rainfall, discharge at S-79 occurred from Feb 15 to Feb 18 and
averaged 150 cfs for the week. The concentration of chlorides at the Olga
Plant is 180 mg/l. In general, average
salinity declined over the past week, with the largest changes occurring near
S-79 where discharges occurred. 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)
|
16.7 (17.6)
|
16.5 (17.7)
|
Rt.
31 Bridge
|
16.8 (18.1)
|
19.0 (19.8 )
|
I-75
Bridge
|
NA (NA)
|
20.2 (21.2)
|
Ft. Myers
Yacht Basin
|
23.6 (23.9)
|
23.8 (23.8)
|
Cape Coral Bridge
|
26.9 (27.1)
|
30.7 (30.8)
|
Shell
Point
|
34.2 (34.3)
|
35.5 (35.4)
|
Salinity
at the Ft. Myers surface sensor remains above the
1-day MFL criterion of 20 ppt. The current surface salinity of 16.7 ppt at S-79 is 3.3 ppt below the
maximum weekly average of 20.0 ppt achieved in May
2001 during the 2000 – 2001 drought. Salinity at the Cape Coral Bridge
is near (surface) or above (bottom) the upper limit of the optimal range for the
oyster, Crassostrea virginica. Conditions in the upper estuary east of Ft. Myers
are poor due to high salinity. Based on
the salinity tolerances of oysters conditions
downstream of Cape Coral
are fair.
FWRI reports that no Karenia brevis, the Florida
red tide organism, was detected this week in water samples collected alongshore
between Pinellas and Collier counties.
Water Conservation Areas
Poor dry-season recession rates
dominate the entire region. Reversals
dominate everywhere due to the heavy rain.
Maximum increase in stage was 0.43 ft at gauge 63 (NE WCA-3A). Minimum
stage increase was 0.09 ft at Gauge 76 (northern WCA-3B). Despite the reversals, the water depth
criteria for water bird foraging remained much the same as last week. Stages in WCA-1 are
now above Regulation, WCA-2A marsh remains above
regulation (note: canal levels dropped sharply due the opening of the S-11’s),
and WCA-3 stages are now only slightly below
regulation. Stages are now greater than
they were a month ago.
Everglades National
Park
Everglades
National Park (ENP) wetland water levels increased in
response to this precipitation. Shark River Slough (station P33) and southern Taylor Slough.
(at Craighead Pond) both posted water levels up by
approximately 1 inch from last week’s readings.
The most significant rise was observed at the Taylor Slough
Bridge, where it
increased by nearly 14 inches over the seven day period. Stage increased by a more modest amount
(0.4”) in the ENP panhandle (station EVER6) where less rain was recorded.
Despite
the rain, salinity concentrations remained generally stable in Florida Bay.
Salinity held in the mid-upper 20s at Trout Creek. At the mouth of Taylor River
salinity read just above 20 psu for another
week. Salinity concentrations in the
Taylor ponds were in the teens for much of the week before dropping into single
digits over the weekend; the 30 day moving average concentration at Argyle
Hendry (station TR, used to track Florida Bay MFL criterion) was at 7.2 psu as
of Sunday, 2/17. Salinity concentrations
were in the low-20s last week at Little Madeira Bay and in the north-central
Bay areas of McCormick
Creek & Terrapin Bay.
Whipray
Basin remained just over
33 psu as of Sunday, 2/17. As a whole these salinity concentrations are
still near seasonal norms. The exception
to this trend is out west, in the SRS outflow at Tarpon Bay,
where salinity remains above its seasonal average, measuring near 15 psu as of Sunday 2/17.
Water Supply
Water
levels in the upper and lower Kissimmee
Basin and Lower
West Coast increased slightly this past week, and remain below
their historical average conditions for this time of year. Water levels in the Lower
East Coast are still near or slightly above their historical
averages and most wells recorded modest increases in water levels this past
week. Water levels in the Upper East Coast remain above their historic
averages. Surface and groundwater levels
in Water Conservation Areas 1 and 2 are now near their historic averages as a
result of local rainfall. Water levels
in WCA 3A continue to remain below their historic
averages and were somewhat lower this week.
Water levels in the southernmost portion of Miami-Dade County
are now below average historic conditions.
Six
out of eleven water supply risk measures are in the “high” risk category
including the projected Lake Okeechobee Stage (SSM),
the Palmer Index for Tributary Conditions, the CPC Precipitation Outlook, and
Lower East Coast Service Areas 1, 2 and 3.
The
LOK Seasonal Net Inflow and the LOK
Multi-Seasonal Net Inflow Forecasts remain at “medium” risk this week. Water Conservation Areas 1, 2A and 3A
continue to be in the “low” risk category.
Chlorides
at the Olga WTP on the Caloosahatchee River
are now at 180 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