MEMORANDUM
TO: Chip Merriam, Deputy Executive Director,
Water Resources
FROM: SFWMD Staff
Environmental Advisory Team
DATE: October
9, 2007
SUBJECT: Weekly Environmental Recommendation
for Systems Operations
Recommendation
No
regulatory releases
to the south or estuaries are recommended.
Background
Drier this week. Drier air is moving over the District from
the northeast and this should dramatically decrease daily shower coverage
beginning today. Showers that do develop
will be focused east and south each day this week. A low pressure system currently in the
northwest
The upper
Kissimmee Basin received 1.97 inches of rainfall over the last 7 days to bring
the 130 day total to 28.26 inches (100% of average) and the lower basin
received 1.10 inches to bring the total for the last 130 days to 27.20 inches
(102% of average). In most of the upper basin
lakes, stage has risen approximately 0.3 feet in the last seven days. Approximately 250 cfs continues to be released from
Flow has been reestablished to the
According to the USACE
web site,
Monthly submerged-aquatic-vegetation (SAV) monitoring was completed during the past week. SAV was present at
21 of 32 sites sampled across the southern and western sides of the lake. The macroalga Chara continues to be the dominant SAV, although the vascular plant Vallisineria
is being found with increasing frequency.
No algal blooms were observed during this sampling. The latest monitoring data support a
continued trend of increasing water clarity and SAV
abundance, declining phosphorus concentrations, and a near-absence of severe
algal blooms in nearshore areas of the lake during
the past year.
St. Lucie Estuary
No releases occurred at S-80 over the past
week. 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 |
|
0.3 |
0.4 |
|
HR1 (N. Fork) |
0.3 |
0.4 |
|
|
0.9 |
1.0 |
8.0 – 25.0 |
A1A Bridge |
6.8 |
16.1 |
20.0 – 31.0 |
Rainfall and associated local runoff lowered
average salinity throughout the estuary last week. Average salinity for the week was below the
preferred at the Roosevelt and A1A Bridges. Based on
the salinity tolerances of the oyster, Crassostrea
virginica, salinity conditions in the estuary are
poor.
Caloosahatchee Estuary
Discharge at S-79 averaged 188 cfs
over the past week. The concentration of
chlorides at the Olga Plant is 76 mg/l.
Average salinity increased slightly throughout the estuary last week. Data for specific sites are given below in
parts per thousand (ppt). The
|
Weekly Average Salinity (ppt) |
|
Sampling Site |
Surface |
Bottom |
|
4.7 |
4.7 |
Rt. 31 Bridge |
3.6 |
4.9 |
I-75 Bridge |
3.5 |
6.6 |
|
NA |
NA |
|
17.13 |
23.1 |
Shell Point |
26.7 |
28.1 |
Salinity conditions throughout the system are good.
FWRI reports that no Karenia brevis, the
Water Conservation Areas
The lack of rain, relative to
evaporation, lead to poor re-hydration rates in WCA-3A, 3B, and NE Shark River Slough. Decreasing water levels at these locations
ranged from -0.04 ft/wk to -0.45 ft/wk in central 3A. Increasing water levels
occurred in the northern regions and averaged +0.25 ft/wk. Water depths remain good for this time of
year because all locations have at least 1.0 ft of water. Stages in WCA-1 are
no longer in Zone A2 and are now at Regulation.
Stages in WCA-2A are almost 1 ft above
regulation and stages in WCA-3 are still below
regulation.
Everglades National Park (ENP)
wetland water levels increased as a result of last week’s rain event on Oct 1st. In some areas, though, these water level
increases were substantially less than one would expect given the high rainfall
totals, suggesting a significant movement of flow downstream (assuming ET has
changed little over recent weeks).
Due to rainfall and strong discharge moving out of
the coastal creeks toward Florida Bay, salinity dropped across much of the
system again last week. In one month’s
time salinity has declined by an impressive 7 – 20 psu
in the eastern and central Bay, providing an important buffer for the upcoming
dry season. Salinity concentrations at
both Trout Creek and
Water Supply
Water levels in the upper and lower Kissimmee Basin
(KB) and Lower West Coast (LWC) continue to remain
near low levels for their periods of record, with an overall increase in the KB
and a slight decline from last week in the LWC. Water levels improved to the highest
percentile in the Upper East Coast and many areas in the Lower East Coast
(especially
The short-term WSE
tributary indices indicate the regions north of the lake have improved. The
30-Day Net Rainfall has risen in the past two weeks and is in the wet range.
The Two-Week Moving Average S65E Flow is in the
normal range after two weeks of above-average rainfall. However,
the long-term Palmer Drought Severity Index (PDSI)*
as of 10/06/2007 indicates that the tributaries north of the
Four out of eleven water supply risk measures are
in the “high” risk category this week – an improvement from last week –
including the projected Lake O Stage (SSM), and Lower
East Coast Service Areas 1, 2 and 3 (by virtue of being under water
restrictions). The LOK
Seasonal forecast and Palmer Drought Severity Index are at “medium” risk.
Water Conservation Areas 1, 2A, and 3A, the CPC Precipitation Outlook, and the LOK Multi-Seasonal Forecast are at low risk.
The water level in
WSE
(
The current
CC: George
Horne