MEMORANDUM
TO: Chip
Merriam, Deputy Executive Director, Water Resources
FROM: SFWMD Staff Environmental Advisory Team
DATE: November 13, 2007
SUBJECT: Weekly
Environmental Recommendation for Systems Operations
Recommendation
No Lake Okeechobee regulatory releases to the
south or estuaries are recommended.
Background
Showers with minor rains east through tomorrow. An inverted trough off the southeast coast of
Florida is creating low level convergence and launching shallow showers
westward over eastern sections of the District.
Most showers are moving and inland over Martin/St. Lucie, but this
activity should drift southward this afternoon and evening. Look for a similar story tomorrow before a
cold front sweeps through the state on Thursday. Dry and cooler conditions will then prevail
through the weekend. Another cold front
is expected to move through in about a week, but little rainfall is expected
into the Thanksgiving weekend. The next
ten days precipitation outlook is below average with moderate confidence.
Over the last 7 days, the upper
Kissimmee Basin received 0 inches of rainfall to bring the 30 day total to 2.59
inches (96% of the long-term average) and the lower basin received 0 inches to
bring the 30 day total to 2.29 inches (91% of the long term average). During the last week, water levels in the upper
basin lakes were steady. Water level in
Flow has been reestablished to the
According to the USACE
web site,
Continued high winds prevented completion of the
November submerged-aquatic-vegetation (SAV) survey
last week and conditions on the lake remain turbid. In the pelagic zone, average TSS increased from 29.9 mg/L in September to 81.1 mg/L in
October and average TP increased from 121 ppb to 222
ppb. A more modest increase in TSS was documented for nearshore
sites (5 mg/L in September and 6.5 mg/L in October) and average TP was 41 ppb during both months.
St. Lucie Estuary
There were no releases through S-80 over the past
week. The C-24 canal discharge is down
from last week to about 294 cfs at S-97. Discharges at S-49 on the C-23 canal are currently
229 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 weeks (in parenthesis).
|
Weekly Average Salinity (ppt) |
|
|
Sampling Site |
Surface |
Bottom |
Envelope |
|
2.5 (1.8) |
2.9 (1.8) |
|
HR1 (N. Fork) |
7.3 (2.12) |
10.3 (4.52) |
|
|
9.7 (5.63) |
12.1 (7.91) |
8.0 25.0 |
A1A Bridge |
17.9 (15.53) |
24.4 (23.84) |
20.0 31.0 |
Salinity conditions
improved by increasing this week throughout the estuary. Both the surface and bottom salinity are now
up to the preferred range at the
Caloosahatchee Estuary
S-79 has not been recording discharge values since
last Tuesday when the previous average weeks discharge was 24 cfs. Also, no
current chloride values were reported at the structure. Average salinity increased last week by more
than 2 ppt in the upper estuary, including at the
|
Weekly Average Salinity (ppt) |
|
Sampling Site |
Surface |
Bottom |
|
10.9 (8.1) |
12.3 (8.9) |
Rt. 31 Bridge |
10.2 (7.8) |
13.7 (9.1) |
I-75 Bridge |
10.5 (8.1) |
14.2 (12.0) |
|
15.4 (13.3) |
17.1 (16.4) |
|
22.3 (22.5) |
24.5 (24.1) |
Shell Point |
30.0 (29.5) |
30.9 (30.6) |
Salinity conditions throughout the system remain
good seaward of
Water samples taken last week (reported on Nov 9 by
FWRI) detected only background concentrations of red
tide (Karenia brevis)
along portions of
Water Conservation Areas
Dry season recession rates now predominate the entire region, setting the stage for
significant dry downs and peat burns if these rates continue. Water depths decreased by 0.17 in WCA-1, 0.22 in WCA-2A, 0.14 in
northern WCA-3A, 0.11 in NESRS,
but only by 0.05 in WCA-3B. Water depths are typically between
2-3 ft, at this time of year, in the WCAs. However, WCA-1 and WCA-2A are just barely above 2.0 ft and all of WCA-3 has less than 2 ft of water. Stages in WCA-1 are
within Zone A2, WCA-2A remains well above regulation,
and stages in WCA-3 remain below regulation.
The weekly RAINDAR basin-wide spatial average
of 0.03 reflected very little precipitation falling over this area (or any
part of south
Salinity either increased slightly or remained
stable across
Water Supply
Water levels in the upper and lower
Six 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, the LOK 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.
The CPC Precipitation Outlook and Multi-Seasonal
Net Inflow Forecasts remain at medium risk this week.
WSE
(
The current
CC: George
Horne