MEMORANDUM
TO: Chip
Merriam, Deputy Executive Director, Water Resources
FROM: SFWMD Staff Environmental Advisory Team
DATE: February 5, 2008
SUBJECT: Weekly
Environmental Recommendation for Systems Operations
Recommendation
No Lake Okeechobee regulatory releases to the
south or estuaries are recommended.
Background
Some
rains developing north to south Thursday through Saturday. High pressure will hang on through tomorrow
afternoon before an upper level trough and attendant cold front slide slowly
through the peninsula. Look for some
showers to focus north of the Lake late Thursday and around the Lake on Friday, then minor rains south Saturday before a
secondary surge shoves drier and cooler air down the peninsula by Sunday. Subsequent hope for rains arrives in 8-9
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 0 inches of rainfall to bring the 30-day total to 2.99 inches, which
was 128% of the long term average, and the lower basin received 0 inches to
bring the 30-day total to 1.04 inches, which was 56% of average. Water levels in the upper basin lakes appear
to have stabilized from rainfall in recent weeks. Water levels are at or below regulation
schedules for respective lakes.
Lake Kissimmee (S-65) continued discharging approximately
250 cfs to the Kissimmee River.
Releases from Lake
Toho (S-61) have
decreased from 700 cfs to 0 cfs. No other releases are being made in the upper
basin. Flow has been reestablished to
the Kissimmee River for 195 days (S-65
re-opened on 07/18/07). Dissolved oxygen
concentrations in the river channel of the Kissimmee River
ranged from 6 mg/L to 8.1 mg/L with an average of 8.1 mg/L.
Lake Okeechobee
According
to the USACE web site, Lake
Okeechobee stage is 10.05’ NGVD, which
is 0.01’ lower than a week ago and 0.07’ lower than a month ago. The current stage is 1.53’ lower than it was
a year ago and 4.66’ below its historical average for this time of year. The lake continues to receive inflows of
approximately 250 cfs from the Kissimmee River (S65E). No major
outflows are reported.
Monthly
submerged aquatic vegetation (SAV) monitoring is
being performed this week. Initial
reports from the south end of the lake are that water clarity is excellent but SAV is sparse and limited to the macroalga
Chara.
The January water-quality monitoring trip was performed on the 29th
but data from that trip are not yet available.
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 not available. 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 (South Fork)
|
11.75 (11.2)
|
15.53 (14.2)
|
|
HR1 (North Fork)
|
16.53 (16.5)
|
19.01 (18.27)
|
|
Roosevelt Bridge
|
19.51 (19.2)
|
20.51 (20.2)
|
8.0 – 25.0
|
A1A Bridge
|
25.70 (27.3)
|
27.27 (28.7)
|
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 19.51 ppt at the Roosevelt
Bridge is 8.5 ppt below the maximum weekly average of 28.0 ppt achieved in May 2001 during the 2000 – 2001 drought (last week’s difference was 8.8 ppt).
Based on the salinity tolerances of the
oyster, Crassostrea virginica,
salinity conditions in the estuary are good.
FWRI reports that no water samples were collected
this week from the east coast of Florida.
Caloosahatchee Estuary
There
were no releases through S-79 from Lake Okeechobee.
The 30-day average discharge from S-79
is 86 cfs. The
concentration of chlorides at the Olga Plant is 180 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)
|
17.03 (16.9)
|
17.63 (17.8)
|
Rt.
31 Bridge
|
17.29 (17.7)
|
20.05 (19.5)
|
I-75
Bridge
|
NA
|
21.10 (20.5)
|
Ft. Myers
Yacht Basin
|
23.95 (23.6)
|
24.24 (23.6)
|
Cape Coral Bridge
|
26.15 (25.3)
|
30.82 (30.3)
|
Shell
Point
|
34.48 (33.8)
|
35.86 (35.3)
|
The
salinity at all the recorders slightly increased with the exception of the
bottom salinity at S79 and the surface salinity at Rt. 31 Bridge. The current surface salinity of 17.03 ppt at S-79 is 2.97 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 Pinellas
and Collier counties contained no Karenia brevis, the Florida
red tide organism.
Water Conservation Areas
Good dry-season
recession rates continue to dominate the region. The only region with poor or fair recessions
is North East Shark River Slough. Here,
the hydrology is in spatial discourse, such that one region has a recession
rate that is too fast, while another region has a recession rate that is too
slow. And where, to make things even
worse, good depths are not corresponding to good recession rates. Regulation stages remain where they have been
for the last few months. Stages in WCA-1 are slightly below Regulation, WCA-2A
remains above regulation, and WCA-3 stages continue
to be significantly below regulation.
Everglades National
Park
Everglades
National Park (ENP) wetland water levels fell in
response to this lack of precipitation. Water level at Taylor
Slough Bridge
dropped by 1.2”, falling to 1.8’ below ground surface. Shark River Slough.
(station P33) and southern Taylor Slough. (at Craighead Pond) also posted declines of nearly 0.75” and
1”, respectively. The ENP panhandle saw the smallest weekly decline of only 0.1”
(likely a residual effect of higher rainfall totals in this area the week
prior).
Salinity
concentrations increased slightly or remained stable in Florida Bay
for another week. Salinity remained in
the lower-mid 20s at Trout Creek. At the
mouth of Taylor River salinity read just above 20 psu for much of the week. Data have been unavailable for the Argyle Hendry
“TR” platform since 1/30, a report on the 30 day
running average concentration for MFL tracking is not
possible. The platform at Whipray
Basin recorded increasing
salinity in the central Bay, up to near 32 psu as of
Sunday, 2/3. 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 15 psu
as of Sunday 2/3.
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 near or 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 LOK
Seasonal Net Inflow Forecast and Lower East Coast Service Areas 1, 2 and 3.
The
LOK Multi-Seasonal Net Inflow Forecasts remain at
“medium” risk this week. Water
Conservation Areas 1, 2A continue to be in the “low” risk category and
Conservation Area 3A is now at “medium” risk.
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