M E M O R A N D U M
TO: Chip
Merriam, Deputy Executive Director, Water Resources
FROM: SFWMD
Staff Environmental Advisory Team
DATE: June 17,
2008
SUBJECT: Weekly
Environmental Recommendation for Systems Operations
Recommendation
No
Lake Okeechobee regulatory releases to
the south or estuaries are recommended.
Background
Above
average rains south today and tomorrow.
A developing mid to upper trough extends down into the eastern
Over the last
seven days, the upper Kissimmee Basin received 1.97 inches of rainfall to bring
the 30 day total to 4.43 inches (82% of average), and the lower basin received
2.34 inches to bring the 30 day total to 4.18 inches (78% of average). The spring recession of the regulation schedule
has ended in the upper basin lakes.
Consequently, releases have ended from all lakes except for minimal
releases from
In the upper basin, snail kites
continue to nest on East Lake Toho,
Flow has been
reestablished to the
Dissolved oxygen
concentrations in the river channel of the
According to the USACE web site,
May water-quality monitoring
results are now available. Fourteen of
the 25 monitoring stations had sufficient water for sampling. Total P averaged 185 ppb lakewide
(compared to 111 ppb in April) and 52 ppb at nearshore
stations (compared to 33 ppb in April).
Total suspended solids (TSS) averaged 68 ppm lakewide (compared to 35 ppm in April) and 14 ppm
at nearshore stations (compared to 6 ppm in April).
The monthly
submerged-aquatic-vegetation (SAV) survey was
completed last week. Twenty six sites
had sufficient water for sampling, and all sites had water clarity conducive to
plant growth (secchi depth > 50% of total depth). The macroalga Chara remains the dominant SAV
species and was found at 15 of the 26 sites.
The vascular SAV species Vallisneria
americana was present 8 of the 16 sites sampled
near the northern and western shorelines but continues to be absent in the
south (10 sites sampled). Other
observations indicate that Vallisneria beds
continue to expand along the western shoreline, but recent declines in lake
level have exposed some of these beds.
Approximately 2000 tires that
had been illegally dumped on
St. Lucie Estuary
There were no releases
through S-80 from C-44 and S-49 from C-24 over the past week. An average discharge of 13.65 cfs from S-48 of C-23 occurred over the past week. 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). The surface salinity
at A1A Bridge is a three day average.
|
Weekly Average Salinity
(ppt) |
|
|
Sampling Site |
Surface |
Bottom |
Envelope |
|
18.05 (18.06) |
20.77
(20.11) |
|
HR1 (N. Fork) |
21.05 (20.92) |
23.42 (22.16) |
|
|
24.22 (23.72) |
25.42 (24.43) |
8.0 – 25.0 |
A1A Bridge |
29.83
(29.82) |
NA (30.31) |
20.0 – 31.0 |
Compared with salinities of
the previous week, average salinity increased slightly throughout the estuary. The surface salinities at both Roosevelt and A1A Bridge are just within the upper limit of the preferred
range. The bottom salinity at
Caloosahatchee Estuary
An average weekly discharge
of 111 cfs occurred at S-79 and 230 cfs occurred at S-77.
No discharge occurred at S-78.
The concentration of chlorides at the Olga Plant was 228 ppm on June 16, down from 232 ppm
in the beginning of this reporting period.
Current weekly averages (in bold) may be compared to last week’s data
(in parenthesis).
|
Weekly Average Salinity
(ppt) |
|
Sampling Site |
Surface |
Bottom |
|
17.84 (19.97) |
20.06
(21.53) |
Rt. 31 Bridge |
18.25
(20.20) |
22.68 (22.91) |
I-75 Bridge |
20.71 (21.80) |
22.55
(23.03) |
|
24.67 (26.11) |
25.67
(26.50) |
|
30.04 (31.73) |
29.98
(32.16) |
Shell Point |
35.08 (35.70) |
35.22
(36.46) |
Average salinities dropped
about 1-2 ppt throughout the estuary. Average salinity at the
No Karenia brevis, the
Water Conservation
Areas
Stages increased
throughout the WCA’s in response to increasing
rainfall amounts and extent. Wet season
precipitation exceeded evapotranspiration causing
stages to increase from a low of 0.02 ft in WCA-2B to
a high of plus 0.55 ft in WCA-3B. Despite increasing stages, wading bird
foraging depths continue to be fair in WCA-1, good in
WCA-2A and fair in WCA-3A. Stages are currently below regulation in WCA-1, slightly above regulation in WCA-2A
and within the E1 zone of the WCA-3A Regulation
Schedule
Rainfall platforms with
sufficient data showed a wide range, from 0.2” (in
Salinity across
Wildlife
A limited June nest count
indicated a total of 11175 nests (3400 egrets and 7775 White Ibis nests) in the
LNWR, on June 1st. Casual observations
indicate that these late breeding birds continue to forage in the LNWR, WCA-2A and in STA’s, and that birds will fledge over the next 2-5 weeks
if water levels do not rise too much or too quickly.
Water Supply
Although there was some
scattered rain last week, most water levels declined across most of the
District. Water levels in the upper and
lower
The Water Supply Risk
Indicators were not available at the time of this writing.
A review of the Minimum Flows
and Levels (MFL) data for this month indicates that
the
LORS2008 (
The current
CC: George Horne