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 10,
2008
SUBJECT: Weekly
Environmental Recommendation for Systems Operations
Recommendation
No
Lake Okeechobee regulatory releases to
the south or estuaries are recommended.
Background
Scattered
showers and some strong storms focused north and east today. An upper level low near
Over the last
seven days, the upper Kissimmee Basin received 1.17 inches of rainfall to bring
the 30 day total to 2.45 inches (54% of average), and the lower basin received
0.65 inches to bring the 30 day total to 1.84 inches (40% 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
Flow has been
reestablished to the
Dissolved oxygen
concentrations in the river channel of the
According to the USACE web site,
The monthly Submerged Aquatic
Vegetation (SAV) survey is underway. Water transparency is excellent at the south
end of the lake and the macroalga Chara is spreading
rapidly but vascular SAV remains absent. Chara is also expanding near Clewiston and north of
Cochran’s Pass. Transparency is also
good along the western shoreline, where beds of Vallisneria
continue to expand. The northern
shoreline will be surveyed for SAV today.
An apple snail egg survey was
conducted in the littoral zone during the last week of May. Ten clusters were found in the vicinity of
Indian Prairie in the northwest marsh. This is the same location where egg clusters
were found during an identical survey in April. Findings to date indicate that the continued
drought has eliminated apple snails across most of the littoral zone.
Wildfires continue to burn in
the lake’s littoral zone but are not expanding primarily due to a lack of fuel.
St. Lucie Estuary
There were no releases
through S-80 from C-44, S-48 from C-23, and S-49 from C-24 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).
|
Weekly Average Salinity
(ppt) |
|
|
Sampling Site |
Surface |
Bottom |
Envelope |
|
18.06 (16.64) |
20.11
(18.88) |
|
HR1 (N. Fork) |
20.92 (21.40) |
22.16 (21.98) |
|
|
23.72 (23.48) |
24.43 (24.27) |
8.0 – 25.0 |
A1A Bridge |
29.82
(29.56) |
30.31
(30.67) |
20.0 – 31.0 |
Compared with salinities of
the previous week, average salinity increased by 2 ppt
at Palm City Bridge and stayed about the same at Roosevelt Bridge (about 24 ppt), A1A Bridge (about 30 ppt), and HR1 (about 21 ppt). The salinities
at both Roosevelt and A1A Bridge are just within the
upper limit of the preferred range.
Salinity conditions in the estuary are considered fair, based on the
salinity preference of the oyster, Crassostrea
virginica, at
Caloosahatchee Estuary
No discharge occurred through
S-79 during the past week. An average
weekly discharge of 227 cfs occurred at S-77 through
Sunday. On Monday 14 cfs went back into
Due to technical
difficulties, salinity readings from the six stations in the Caloosahatchee
Estuary are not accessible at this point.
Coordination is ongoing with the District IT staff to solve the problem. Average salinities of the previous week were
provided in parenthesis. Based on local
hydrologic conditions and salinity data collected by other agencies, it can be
reasonably assumed that salinity conditions in the Caloosahatchee Estuary
remain similar to that in the previous week.
Salinity data collected by both USGS (Marker
52, and Sanibel-Captiva
Conservation Foundation indicate that average salinity from June 3 to 10 at Ft.
Myers was about 26-27 ppt, similar to that of the
previous week. This is about 6-7 ppt above the 1-day MFL criterion
of 20 ppt.
Salinity at Shell Point monitored by Sanibel-Captiva
Conservation Foundation was about 36 to 38 ppt during
the past week.
|
Weekly Average Salinity
(ppt) |
|
Sampling Site |
Surface |
Bottom |
|
NA (
19.49) |
NA (20.85) |
Rt. 31 Bridge |
NA (19.47) |
NA (21.58) |
I-75 Bridge |
NA (20.28) |
NA (22.67) |
|
NA (26.48) |
NA (27.23) |
|
NA (31.74) |
NA (31.95) |
Shell Point |
NA (35.88) |
NA (36.60) |
In summary, salinity
conditions in the upper estuary east of
No Karenia brevis, the
Water Conservation
Areas
Stages are declining
throughout the WCA’s.
Although it is the beginning of the rainy season, good recession rates
and water depths exist in the
Rainfall was patchy across
Everglades National Park (ENP) and
In response to the spatial
pattern of rainfall, ENP wetland water levels were
relatively stable or dropped slightly last week. The water level was unchanged at SRS (station
P33) and increased slightly by 0.1” in the panhandle (station EVER6) over the week.
To the east, water level saw declines of 1.8” at
Salinity in
Concentrations increased slightly, remaining in the middle to upper 30s across
most of northeast
Water Supply
Although there was some scattered
rain last week, most water levels decreased across most of the District. Water levels in the upper and lower
There were some changes
(deterioration) in the water supply risk indicators since last week. Five out of the eleven water supply risk
indicator parameters are now in the “low” risk category, including the CPC
Precipitation Outlook, the Lake Okeechobee Seasonal and Multi-seasonal Net
Inflow Forecast, and Water Conservation Areas 1 and 3A.
Three out the eleven water
supply risk indicators are now in the “medium” risk category, including LEC Service Areas 1, 2 and 3.
Three risk measures are now
in the “high” risk category - the projected Lake Okeechobee Stage (Water
Shortage Management Band), Palmer Index for Tributary Conditions (Very Dry) and
WCA 2A.
LORS2008 (
The current
CC: George Horne