MEMORANDUM
TO: Chip
Merriam, Deputy Executive Director, Water Resources
FROM: SFWMD Staff Environmental Advisory Team
DATE: November 6, 2007
SUBJECT: Weekly
Environmental Recommendation for Systems Operations
Recommendation
No Lake Okeechobee regulatory releases to the
south or estuaries are recommended. It
was recommended that the S-65 flows be reduced from 500 cfs
to 250 cfs in order to extend the duration of flow to
the
Background
Very
little rain the next week or so. Some
limited moisture will begin to move back into eastern and southern areas today
ahead of the next cold front. This
moisture should allow an isolated shower or two south
later today and tonight. As the cold
front pushes into the area and stalls, scattered showers activity will affect
eastern areas Wednesday and Thursday. A
low is then forecast to develop off the coast of the
Over the last 7 days, the upper
Kissimmee Basin received 1.29 inches of rainfall to bring the 30 day total to
2.92 inches (107% of the long-term average) and the lower basin received 0.73
inches to bring the 30 day total to 2.56 inches (99% of the long term average). Wet season totals were 30.63 inches (100% of
average) for the upper basin and 29.32 inches (102% of average) for the lower
basin (Daily Rainfall Report 11/1/07). During the last week, water
levels in almost all of the upper basin lakes increased slightly. Water level in
Only
Anecdotal observations suggest that
native species of submerged aquatic vegetation and apple snails are doing well
in
According to the USACE
web site,
Recent high winds have increased turbidity in the
lake. Initial results of the November
submerged-aquatic-vegetation (SAV) survey indicate
that SAV coverage has been maintained at the southern
end of the lake despite declining secchi depth
readings. However, continued deterioration
in water clarity may reduce SAV cover in the coming
weeks.
St. Lucie Estuary
No releases occurred at S-80 over the past
week. The C-24 canal is discharging
about 548 cfs at S-97. No discharge is occurring at S-49 on the C-23
canal. Weekly average salinities at the
four monitoring sites in the St. Lucie are given below in parts per thousand (ppt).
|
Weekly Average Salinity (ppt) |
|
|
Sampling Site |
Surface |
Bottom |
Envelope |
|
1.79 |
1.84 |
|
HR1 (N. Fork) |
2.12 |
4.52 |
|
|
5.63 |
7.91 |
8.0 25.0 |
A1A Bridge |
15.53 |
23.84 |
20.0 31.0 |
There was little change in average salinity over
the past week. Only bottom water at the A1A Bridge fell within the preferred salinity range. Based on the salinity tolerances of the
oyster, Crassostrea virginica,
salinity conditions in the estuary are poor to fair.
Caloosahatchee Estuary
Discharge at S-79 averaged 24 cfs
over the past week. The concentration of
chlorides at the Olga Plant is 103 mg/l.
Average salinity in the estuary changed little over the past week. Data
for specific sites are given below in parts per thousand (ppt).
|
Weekly Average Salinity (ppt) |
|
Sampling Site |
Surface |
Bottom |
|
8.12 |
8.85 |
Rt. 31 Bridge |
7.83 |
9.05 |
I-75 Bridge |
8.11 |
11.97 |
|
13.30 |
16.44 |
|
22.52 |
24.14 |
Shell Point |
29.47 |
30.57 |
Salinity conditions throughout the system are good
seaward of
Water Conservation Areas
Water depths decreased by 0.41 and 0.15 in WCA-2A and WCA-2B,
respectively. Water depth changes in
other WCA impoundments did not change
appreciably. Water depths averages for WCA impoundments all exceeded 1.3 with highest average
depths occurring in WCA-2B (3.3). Stages in WCA-1 are
within Zone A2, WCA-2A remains well above regulation,
and stages in WCA-3 below regulation.
Rainfall totals were moderate across Everglades
National Park (ENP) and FL Bay last week. Wetland stations where data was available (many
stations was not recording) received between 0.75 1.1 of rainfall. The weekly RAINDAR
basin-wide spatial averages were ~ 0.4 for the ENP
basin and just higher at 0.9 to the east in the C-111 basin, in close
agreement with the few stations from which we did receive data last week.
ENP wetland water levels
displayed mixed trends. Water levels
both at Shark River Slough (P33) and at the southeastern end of ENP in the panhandle (EVER6) were
nearly unchanged (up by 0.2, down by 0.1, respectively).
Salinity remained generally low and stable across
FL Bay, with the exception of a brief reversal at the end of the week just
prior to the passage of the weekend cold front.
Strong flow from the Everglades down to the Bay through both Trout Creek
and Taylor River allowed salinity to remain in the single digits for much of
the 7 day period, with the exception of a brief reversal Friday-Saturday in
which salinity shot up (10-20 psu) before dropping
back down again. Salinity in the
Water Supply
Water levels in the upper and lower
Five out of eleven water supply risk measures are
in the high risk category this week - the projected Lake O Stage (SSM), the Palmer Index for Tributary Conditions 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.
The CPC Precipitation Outlook and the LOK Seasonal and Multi-Seasonal Net Inflow Forecasts remain
at medium risk this week.
WSE
(
The current
CC: George
Horne