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: September 2, 2008
SUBJECT: Weekly
Environmental Recommendation for Systems Operations
Recommendation
Overall the Central and
Background
Drier
conditions Tuesday, and Wednesday; followed by storms on Thursday. Hurricane Gustav is spinning down over
Over the last
seven days, the upper Kissimmee Basin received approximately 1.5 inches of
rainfall and the lower basin received approximately 1.7 inches (Seven Day Raindar Estimate 8/26/08 – 9/02/08).
Water levels in
all of the upper basin lakes are at or slightly above their regulation
schedules. Releases are being made from
Water depths on
the floodplain within the restoration project have decreased by about 0.5 feet
over the last week and currently range from 1.0 – 7.7 feet. The floodplain in the restored reach is
completely inundated at this time.
From 8/26/08 to
9/02/08 dissolved oxygen (DO) concentrations in the
According to the USACE web
site,
Total reported inflows are
19324 cfs, with contributions from the
and the L8 at canal point (485 cfs). Back pumping from the EAA is occurring
through S4 at 235 cfs. Outflows of 265 are reported through
S154. No flow data are available for the
S77 or S308.
Last week, field crews re-sampled
74 of the 154 annual mapping grid cells that had Submerged Aquatic Vegetation
(SAV) prior to Tropical Storm Fay. Plants
were still present at all but three cells.
These three cells had very sparse plants initially and the lack of
plants in the post sampling may be due to patchiness and not to wind and wave
effects. Crews reported very little
floating or uprooted vegetation (submerged or emergent), and most of what was
observed was cattail that had been dead prior to the storm. No blooms or toxins were present during
either the July phytoplankton sampling or immediately following Tropical Storm
Fay. A bloom was reported near Port Myacca on 8/29, but a crew sent out Tuesday found no blooms
in that area.
St. Lucie Estuary
During the last week, an
average discharge of 1753 cfs occurred at S-80 from
C-44. Average discharge values through
S-48 from C-23 and through S-49 from C-24 are unavailable 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) and the preferred range (envelope) at the two downstream
sensors. HR1 values are estimated from
two days at the beginning of this week.
|
Weekly Average Salinity
(ppt) |
|
|
Sampling Site |
Surface |
Bottom |
Envelope |
|
0.17 (1.43) |
0.17
(1.44) |
|
HR1 (N. Fork) |
0.15 (0.92) |
0.17(1.20) |
|
|
0.20 (1.89) |
0.20(1.96) |
8.0 – 25.0 |
A1A Bridge |
2.87
(3.82) |
9.75
(4.48) |
20.0 – 31.0 |
Compared with salinities of
the previous week, average salinity in the estuary decreased about 0.8 to 1.8 ppt., except for bottom salinity at A1A Bridge which
increased by 5.3 ppt.
All four monitoring stations are reporting salinities below the
preferred range. Salinity conditions in
the estuary are considered to be poor based on the salinity preference of the
oyster, Crassostrea virginica,
and location in the estuary.
Caloosahatchee Estuary
An average weekly discharge
of 10,311 cfs occurred at S-79. The
concentration of chlorides at the Olga Plant was 30 ppm
yesterday, up from 22 ppm at the beginning of this
reporting period.
Prior to Tropical Storm Fay,
S-78 remained closed with no discharge since June 30th. S-78 average discharge during the last week
was 3993 cfs. The
gates at S-77 have remained closed over the past week.
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 |
|
0.16 (0.16) |
0.15
(0.16) |
Rt. 31 Bridge |
0.16
(0.16) |
NR (NR) |
I-75 Bridge |
0.20
(0.19) |
0.18
(0.18) |
|
0.19 (0.28) |
0.19 (0.28) |
|
0.54 (NR) |
1.13 (NR) |
Shell Point |
7.69 (5.29) |
11.45 (7.35) |
In the estuary, freshwater
conditions extend from S-79 downstream to
Salinity at
No Karenia brevis, the
Water Conservation
Areas
Rainfall did not
keep up with evapotranspiration everywhere and water
depths increased (ft) in some areas and decreased in other, such that:
WCA-1: - 0.06 ft WCA-3A: + 0.25 ft
WCA-2A: + 0.50 ft WCA-3B: + 0.07 ft
WCA-2B: + 0.19 ft ENP: -
0.02 ft
June through
September is usually the time of year when the Greater Everglades (GE) is
expected to continuously rise at the rate of some 0.1 to 0.2 feet per week. However, with the arrival of Tropical Storm Fay
it is no longer necessary or appropriate to track this re-hydration rate. The GE has now reached a state where most of
the sentinel gages are at least 2 feet deep and large areas of the GE are
currently over 2.5 feet. This 2.5 foot
depth is a generalized threshold for tree island inundation where continuous
inundation of more than 120 days is a potential health hazard for islands. Thus, Inundation Days are now being tracked
and some areas of WCA-3A are now 35 days above the tree island threshold.
WCA-1 has dropped
below the regulation schedule. All the
other WCA stages are above regulation, especially WCA-2A, which has been above
regulation since Oct. 1, 2007 (i.e., the last 11 months). It is not possible to
restore drowned tree islands in WCA-2A under this hydrologic regime.
For the most part, stages in Everglades
National Park (ENP) increased. Water
levels rose over two feet in Shark River Slough (station P33) and nearly 1.5
feet at the
Salinity declined slightly
across
Creek salinity continued to
decline last week, although there was a marked pattern of flashy reversals
likely due to the prevailing southerly outflow winds from Hurricane
Gustav. Trout Creek.
salinity decreased into the middle-upper teens during
the week but briefly spiked to over 25 psu on Sunday,
8/31 before dropping back into the middle-upper teens by Monday morning (9/1).
Water Supply
Water levels remained largely
unchanged across most of the District. After enjoying a substantial rise (increase) as a result of Tropical
Storm Fay two weeks ago. Water
levels in the upper and lower
Eight out of the eleven water
supply risk indicator parameters are now in the “low” risk category, including
the CPC Precipitation Outlook, Palmer Index for Tributary Conditions, the Lake
Okeechobee Seasonal and Multi-seasonal Net Inflow Forecast, and Water Conservation
Areas 1, 2A and 3A. The projected Lake
Okeechobee Stage is now in the “low” risk category.
Eight out of the eleven water
supply risk indicator parameters are now in the “low” risk category, including
the CPC Precipitation Outlook, Palmer Index for Tributary Conditions, the Lake
Okeechobee Seasonal and Multi-seasonal Net Inflow Forecast, and Water Conservation
Areas 1, 2A and 3A. The projected Lake
Okeechobee Stage is now in the “low” risk category.
Three out the eleven water
supply risk indicators are now in the “medium” risk category, including LEC
Service Areas 1, 2 and 3.
LORS2008 (
Stages in
CC: George Horne