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: December
2, 2008
SUBJECT: Weekly
Environmental Conditions for Systems Operations
Summary
Water depths on the southern
end of the restored
On October 14th,
the United States Army Corps of Engineers (USACE) initiated baseflow
releases to both estuaries, targeting an overall average release of 450 cfs at S-79 to the
Background
Current
conditions are dry and cool. A secondary
cold front is exiting the southeast coast Tuesday morning. Some clouds will linger behind this front
until the associated upper level trough passes through late Tuesday afternoon
and cool weather will hang on through Wednesday. Otherwise, weak high pressure will dominate
through the remainder of the work week.
A weak cold front arrives Saturday with little or no rainfall. The next chance for appreciable rainfall
appears the middle of next week. The
next ten days precipitation outlook is below average with moderate confidence.
Over
the last seven days, the upper Kissimmee Basin received 0.43 inches of rainfall
to bring the 30 day total to 1.11 inches (45% of average) and the lower basin
received approximately 0.43 inches to bring the 30 day total to 0.63 inches
(29% of average). Stage in Lakes
Kissimmee, Hatchineha and
Florida Fish and Wildlife
Conservation Commission (FWC) will be conducting hydrilla
treatments on
Discharge from
The floodplain in the
restored section of the
Stage in C-38 north of the
current backfilling project is approximately 7-8 feet higher than south of the
backfilling due to water being conveyed around the active construction. In the event of increased inflows through
S65A, culverts can be opened to pass additional water around/through the
construction area.
From 11/25/08 to 12/2/08
dissolved oxygen concentrations in the
According to the United
States Army Corp of Engineers (USACE) web site,
The monthly
submerged-aquatic-vegetation (SAV) survey is being performed this week. The macroalga Chara continues to decline in coverage at the
south end of the lake and was found at only 1 site. Water clarity has also declined with an
average secchi depth:total depth ratio of 0.22 (compared to 0.33 last
month).
St. Lucie Estuary
Over the past week discharge
averaged 214 cfs at
S-80. Discharge from the
|
Weekly Average Salinity
(ppt) |
|
|
Sampling Site |
Surface |
Bottom |
Envelope |
|
3.14 (NR) |
9.62 (7.12) |
|
HR1 (N. Fork) |
14.98 (14.19) |
16.95 (16.97) |
|
|
14.89 (15.09) |
17.27 (17.27) |
8.0 – 25.0 |
A1A Bridge |
23.16 (24.89) |
25.09 (26.11) |
20.0 – 31.0 |
Salinity changed only
slightly throughout the estuary during the past week. Salinity at
Caloosahatchee Estuary
During the last week,
discharge averaged 431 cfs at S-79, 293 cfs at S-78, and 600 cfs at
S-77. The concentration of chlorides at
the Olga Plant was 54 ppm
on November 30th. The current
weekly average salinities (in bold) at the six monitoring sites in the
Caloosahatchee Estuary are given below in parts per thousand (ppt), along with the previous week’s (in parenthesis).
Weekly Average Salinity
(ppt) |
||
Sampling Site |
Surface |
Bottom |
|
4.81 (3.39) |
4.92 (3.41) |
Rt. 31 Bridge |
4.60 (3.57) |
5.89 (3.85) |
I-75 Bridge |
4.92 (3.93) |
7.60 (5.60) |
|
11.00 (7.97) |
13.90 (11.13) |
|
18.71 (16.69) |
20.19 (18.22) |
Shell Point |
29.82 (26.89) |
28.75 (27.48) |
Salinity increased throughout
the estuary. Salinity conditions in the
upper estuary east of
Fish and Wildlife
Research Institute (FWRI) reports that water samples
collected alongshore between Pinellas and Collier counties contained no K. brevis. Monitoring data collected by the River,
Estuary and Coastal Observing Network (RECON) of Sanibel-Captiva
Conservation Foundation (SCCF) indicated that over the last week Chlorophyll
concentrations ranged between 3 and 6.5 µg/L at
Water Conservation
Areas
Stage dropped at
rates considered healthy in WCA-1, WCA-2A and WCA3A. However, structure openings were very
effective in maintaining water levels in WCA-3B and increasing water levels in
Northeast Shark River Slough. These
structure openings were implemented to reduce the high water levels in southern
WCA-3A and supply maximum inflows to Shark River Slough and Taylor Slough.
Average basin weekly stage changes for the week ending on 12-2-08 were:
Stage Change: WCA-1: - 0.03 ft WCA-3A: -
0.15 ft
WCA-2A: - 0.15 ft WCA-3B: +
0.07 ft
WCA-2B: +
0.08 ft NESRS: + 0.21 ft
Despite the fact
that some regions are increasing slightly due to structure openings, the EPA is
no longer at seasonal high water levels.
Water levels are now receding at rates considered typical of a healthy
Landscape scale
depth changes indicate that WCA-3A has changed considerably over the last two
months, while WCA-2A changed considerably over the last one month, and WCA-1
has not changed very much. All three WCA’s are close to the regulation schedule. WCA-2A stage dropped a quarter of a foot and
has been dropping very quickly over the last two months. As a result, thirteen months above regulation
in WCA-2A has come to an end, and the exceedance that
began in mid-July in WCA-3A will end soon.
Stages in
Salinity displayed a general
stable trend in
Water Supply
Water levels continued to
decline slightly across most of the District this week, as a result of
relatively light rainfall. Water levels
in the upper and lower Kissimmee Basin (KB) are now near or slightly below
their average conditions for their respective periods of record. Groundwater levels in the western portion of
the upper KB are generally lower than those in the eastern portion. Water levels in the Lower West Coast are
mostly above their historical averages although wells in the upper
Eight out of the eleven water
supply risk indicator parameters remain in the “low” risk category, including
the projected LOK Stage, the LOK Multi-Seasonal Net Inflow Forecast, Water Conservation Areas 1, 2A and 3A and LEC
Service Areas 1, 2 and 3 (no restrictions).
The CPC Precipitation
Outlook, Palmer Index for Tributary Conditions, and the Lake Okeechobee
Seasonal Net Inflow Forecast are now in the “medium” risk category,
anticipating seasonally dry conditions.
LORS2008 (
Stages in
CC: George Horne