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 9,
2008
SUBJECT: Weekly Environmental Conditions for Systems Operations
Summary
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
It is warmer
with some limited shower activity Tuesday and Wednesday, with showers and
thunderstorms Thursday. Southeasterly
winds are helping moisture to rebound over the area. Some widely scattered shower activity should
pop up mainly east Tuesday and Wednesday.
The next cold front is expected to move through the District Thursday
and generate scattered showers and thunderstorms. A post-frontal trough should keep some clouds
and some spotty light showers over the District on Friday. As this trough stalls over the District,
expect some scattered showers mainly east Saturday. The next ten days precipitation outlook is
near average with low confidence.
Over the last seven
days, the upper Kissimmee Basin received 0.03 inches of rainfall to bring the
30 day total to 0.96 inches (38% of average) and the lower basin received
approximately 0.03 inches to bring the 30 day total to 0.56 inches (27% of
average).
Stage in Lakes
Kissimmee, Hatchineha and
The floodplain in
the restored section of the
Stage in C-38 north
of the current backfilling project is approximately 7.5 feet higher than south
of the backfilling due to water being conveyed around the active construction
to limit turbidity issues. In the event
of increased inflows through S65A, culverts can be opened to pass additional
water around/through the construction area.
Wading bird numbers
were down significantly from October.
Most of the birds were observed in Pool B in one large flock at the
south end of the backfilling construction area on the west side of C-38, in the
large wet prairie area within the Bombing range fence. This area would be dry if we were not
conveying water onto the floodplain to bypass the active construction zone.
Dissolved oxygen (DO)
concentrations in the
According to the
United States Army Corp of Engineers (USACE) web site,
The monthly
submerged-aquatic-vegetation (SAV) survey was completed last week and eight of
the 24 sites sampled had plants (compared to 10 of 30 in November). Vegetation was sparse or very sparse at all
eight sites. The macroalga
Chara was found at one site in the south and one site
in the west. Two vascular species also
were found, Vallisneria (two sites in the west
and one in the north) and Ceratophyllum (four
sites in the north). Water clarity was
the same as it was last month with an average secchi depth:total depth ratio of 0.33.
St. Lucie Estuary
Over the past week
discharge averaged 214 cfs at S-80. Discharge from Lake Okeechobee (
|
Weekly Average Salinity
(ppt) |
|
|
Sampling Site |
Surface |
Bottom |
Envelope |
|
2.93 (3.14) |
9.92 (9.62) |
|
HR1 (N. Fork) |
13.78 (14.98) |
16.17 (16.95) |
|
|
14.85 (14.89) |
17.17 (17.27) |
8.0 – 25.0 |
A1A Bridge |
23.37
(23.16) |
25.17 (25.09) |
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 472 cfs at S-79, 233 cfs at S-78, and 227 cfs at
S-77. The concentration of chlorides at
the Olga Plant was 58 ppm
yesterday. 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 |
|
3.99 (4.81) |
4.13
(4.92) |
Rt. 31 Bridge |
4.27 (4.60) |
4.53
(5.89) |
I-75 Bridge |
4.69
(4.92) |
6.38
(7.60) |
|
9.90 (11.00) |
12.42 (13.90) |
|
17.83 (18.71) |
19.09 (20.19) |
Shell Point |
27.98 (29.82) |
27.01 (28.75) |
Salinity decreased
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 5.5 µg/L at
Water Conservation
Areas
The lack of rainfall
produced stage declines throughout the Water Conservation Areas (see WCA Stages
spreadsheet). Average basin weekly stage changes for this week varied
from no change in Northeast Shark River Slough (NESRS) resulting from continued
managed water releases from WCA-3 to nearly 0.2 ft in WCA-3A. The variability of basin stage changes
resulted from water management plus evaporation:
Stage Change: WCA-1: -
0.06 ft WCA-3A: - 0.18 ft
WCA-2A: - 0.10 ft WCA-3B: - 0.04 ft
WCA-2B: - 0.02 ft NESRS: -
0.00 ft
Annual dry season
recession rates are now being tracked. Seasonal
declines in the Everglades Protection Area ranging from - 0.05' to - 0.016' per
week are considered Good. Recession
rates ranged from Good to Fair throughout the WCA basins.
Water depths are
still locally above desired levels for tree islands at three gauges. The central region of WCA-3A is now below 2.5
feet and only the southernmost station (gauge 65) is above it. Water levels remain high at Gage 99 in WCA-2B
in southern WCA-3A because of ponding.
All three WCA’s are close to or at the regulation schedule
stages. WCA-2 and WCA-3 no longer exceed
these regulation stages.
Data transmission
problems on Dec. 7 preclude reporting 7 day trends, so this week’s Everglades
National Park (ENP) reports reflect six days of data (12/1 – 12/6).
Very little rain
fell across ENP and
Stages in ENP were
generally stable last week. Water level
in Shark River Slough was unchanged but increased 0.7 inch in the ENP
panhandle. In southern Taylor Slough,
water levels at the
Salinity was stable or dropped in
In the north central
Bay, strong northeasterly winds last week allowed salinity to drop from the low
30s in Terrapin Bay and McCormick to the low 20s and upper teens,
respectively. Salinity was steady in the
mid-30s at the central Bay platform in
Water Supply
Water levels are
continuing a declining trend across most of the District this week due to the
light rainfall. Water levels in the
LORS2008 (
Stages in
CC: George Horne