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
30, 2008
SUBJECT: Weekly
Environmental Conditions for Systems Operations
Summary
Inflows from the tributary
basins have continued to taper off and are now in the wet tributary hydrologic
conditions. Stages in Lake Okeechobee (Lake) are within one foot of the intermediate band. The LORSS recommended discharges are up to 3000
cfs at S-79 and up to 1170 cfs
at S-80, and maximum practical discharges to the south if desired or with
minimal impact. The United States Army
Corps of Engineers (USACE) initiated a second pulse release on September 16th,
with an overall release average of 3000 cfs at S-77
and 1500 cfs at S-80. Conditions in Lake Okeechobee are fair, with
some areas of algal bloom formation on the Lake,
and conditions in the estuaries are poor.
Background
Wet again Tuesday, then drier Wednesday and Thursday.
An old frontal boundary remains across the District and upper level
energy continues to stream across the area.
Expect areas of rain and embedded shower activity to move across the
District Tuesday afternoon and evening with heaviest activity focused across
the southern half of the District. The
front should push south of the District overnight so fairly dry conditions are
expected Wednesday and Thursday. A low
pressure system is forecast to develop in the northwestern Caribbean
Wednesday so the front should creep back northward into the District bringing a
return of rains Friday and Saturday. The
next ten days precipitation outlook is above average with low confidence.
Kissimmee Watershed
Over the last seven days, the
upper Kissimmee Basin received approximately 0.64 inches
of rainfall to bring the monthly total to 2.37 inches (41% of average). The lower basin received approximately 0.85
inches to bring the monthly total to 2.34 inches (42% of average. Water levels in all of the upper basin lakes
continue to closely follow their regulation schedules except for Lakes
Kissimmee, Hatchineha and Cypress which are slightly below regulation
and declining. Releases from the upper
chain of lakes have ceased except for minor releases (<100 cfs) from Lakes Myrtle, Hart, Gentry and Alligator.
Discharge from Lake Kissimmee
decreased from 800 cfs to approximately 300 cfs and discharge at S65C is down from 1700 cfs to 700 cfs.
Water depths on the
floodplain within the restoration project area have decreased by about 0.5 to
1.0 foot over the last week. Floodplain
depths in the restored area range from 0.5 to 2.0 feet in general.
From 9/23/08 to 9/30/08
dissolved oxygen (DO) concentrations in the Kissimmee
River ranged from 1.3 mg/L to 4.6 mg/Land averaged 2.9 mg/L, a
significant increase from last week. DO
concentrations were above levels of concern most of the time over the past
week.
Lake Okeechobee
According to the United
States Army Corp of Engineers (USACE) web site, Lake
Okeechobee stage is 14.93’ NGVD, which is 0.13 feet lower than a
week ago, 0.58 feet higher than a month ago, and 5.09 feet higher than it was a
year ago. The current stage is 0.06 feet
above the historical average for this date, and 1.16 feet above the simulated
historical average for the current regulation schedule (LORS2008). Total reported inflows are 1111 cfs (no report for S133), with the greatest contributions
from the Kissimmee River (454 cfs), S71 (152 cfs), S191 (275 cfs), S129 (102 cfs), Fisheating Creek (82 cfs). No back-pumping from the Everglades
Agricultural Area (EAA) is occurring at this time. Pulse releases to the estuaries continue at
1797 cfs through the S77 and 568 cfs
through the S308. Other outflows include 192 cfs to
the L8 at Canal Point.
The bloom that was reported
in the northern part of Lake Okeechobee and in Fisheating Bay last week has been identified by a
District contracted phycologists. Chlamydomonas,
a non-toxin producing green alga, was the dominant species. The cyanobacteria Microcystis and Planktolyngbya
were also present but in low numbers. Toxin concentrations are not yet
available. A crew will be on a
helicopter flight Tuesday afternoon and will report on current condition of the
bloom.
St. Lucie Estuary
During the last week, an
average discharge of 858 cfs occurred at S-80 from
C-44 and 971 cfs at S308 with no discharge at S-97
from C-23 or S-49 from C-24. 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
|
Palm City Bridge (S. Fork)
|
1.14 (0.33)
|
2.08 (0.38)
|
|
HR1 (N. Fork)
|
4.73 (2.23)
|
9.57 (5.45)
|
|
Roosevelt Bridge
|
7.02 (4.32)
|
10.30 (6.36)
|
8.0 – 25.0
|
A1A Bridge
|
16.49 (14.77)
|
NR (23.42)
|
20.0 – 31.0
|
Compared with the previous
week, average salinity increased about 0.7 ppt in the
South Fork to about 3-4 ppt in the rest stations of
the estuary. All four monitoring
stations are reporting salinities below the preferred range, except for the
bottom salinity at A1A Bridge. Salinity
conditions in the estuary are still 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 5032 cfs occurred at S-79, 3558 cfs at S-78, and 3655 cfs at
S-77. The concentration of chlorides at
the Olga Plant was 53 ppm yesterday, up from 43 ppm at the beginning of this reporting period. 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
|
Franklin Locks (S-79)
|
0.22 (0.24)
|
0.22 (0.24)
|
Rt. 31 Bridge
|
0.22 (0.24)
|
0.22 (0.24)
|
I-75 Bridge
|
0.25 (0.26)
|
0.26 (0.27)
|
Ft. Myers Yacht Basin
|
0.24 (0.34)
|
0.24 (0.36)
|
Cape Coral Bridge
|
1.76 (3.45)
|
2.57 (5.17)
|
Shell Point
|
13.30 (16.66)
|
17.42 (19.42)
|
In the estuary, freshwater
conditions extend from S-79 downstream to Cape Coral Bridge. Salinity conditions in the upper estuary east
of Fort Myers are good (30 day average at Fort Myers equals 0.30 ppt).
Compared with the precious
week, a decrease in average salinity of about 2-3 ppt
occurred between Cape Coral
Bridge and Shell
Point. Salinity at Cape Coral Bridge
is below the preferred ranges for both oyster, Crassostrea virginica,
and seagrass, Halodule
wrightii.
Salinity at Shell Point is oscillating with the tide between about 29 ppt to 4 ppt. Therefore, conditions in the lower estuary
between Cape Coral
and Shell Point are considered poor.
Fish and Wildlife
Research Institute (FWRI) reports that no Karenia
brevis, the Florida red tide organism, was detected this
week in water samples collected alongshore between Pinellas and Monroe
counties. Monitoring data collected by the River, Estuary and Coastal Observing
Network (RECON) of Sanibel-Captiva Conservation
Foundation (SCCF) indicated that Chlorophyll concentrations over the last week
were about 4.5-5.5 ug/L at Fort Myers and 1.5 to 4 ug/L at Shell Point.
The dissolved oxygen (DO) concentration at the two locations ranged from
about 4 to 6 mg/L.
Water Conservation
Areas
Water levels are
rising again with the week’s rainfall except for WCA-2A, where depths decreased
by 0.29 foot.
Average water stage changes in each of the Everglades
areas are below.
CHANGE: WCA-1: 0.07 ft WCA-3A: 0.06 ft
WCA-2A: -0.29 ft WCA-3B: 0.16
ft
WCA-2B: 0.12
ft NESRS: 0.40 ft
Water depths in
the Greater Everglades (GE) range from a high of 4.11 feet in the southern
region of WCA-2B to a low of 1.36 feet in central WCA-1. Depths over large areas of the GE exceed 2.5
feet, a generalized threshold for tree island inundation. Continuous inundation beyond 120 days
potentially threatens the health of trees on the tree islands,
Inundation Days are now being tracked.
The southern region of WCA-3A is now 63 days above the tree island
threshold, the ponded region of WCA-2B is now 77 days
above this threshold, and northern and central areas of WCA-2B and -3A are
28-49 days into this 120 day period. The
declining stages in central WCA-2A have dropped depths below this general
threshold.
Stages in WCA-1
have risen slightly this week but are still below the regulation depths and
need to continue to rise. WCA-2A stages
continued to drop but not as much as last week (-0.29 foot compared to -0.62
foot), but are getting closer to their regulation stage. This conservation area has now been above
regulation for one full year. WCA-3A stage has risen slightly this week and has
been above regulation since mid-July.
Everglades National Park
Rainfall prior to the weekend
was light to moderate across much of Everglades National Park (ENP) and Florida Bay but heavier Monday. The highest rainfall totals were to the west,
with areas of Shark River Slough receiving at over 2 inches of rain, with
particularly heavy rainfall last Tuesday.
The basin-wide spatially-averaged weekly RAINDAR totals were 3.0"
and 2.12" in the ENP and C-111 basins, respectively.
Data from ENP were not
available for the full week, so this report covers the period only through
Friday. Stages in ENP wetlands showed
mixed trends last week in response to spatially variable rainfall. Water levels rose 0.6" in Shark River
Slough (station P33) but remained nearly unchanged at Taylor Slough
Bridge for the 5 day
period. To the south, stages decreased
during the same period by approximately 1” at Craighead Pond and 0.25" in
the ENP panhandle (station EVER6).
Salinity trends across Florida Bay were also mixed last week. Seasonably normal salinity was reported in
most nearshore areas, including the Little Madeira
Bay mouth (mid-upper 20s). The creeks
feeding Florida Bay measured near average salinity
before sharply increasing over the weekend into the 20s caused by a flow
reversal (high tides) that sent Bay water northward. Taylor River Pond was
stable for much of the period (under 10 psu), though
data for Pond 5 (USGS platform) indicated that the flow reversal increased
salinity in these areas to above 20 psu by the weekend. District staff will not report on the Taylor River
platform 30 day moving average salinity (used for tracking the Florida Bay MFL
criterion) until receiving updated data through the weekend. Salinity also remained near seasonal norms in
the north central Bay (low-mid 20s in Terrapin Bay
and McCormick Creek) before rapidly increasing over the weekend following a
flow reversal. Salinity at the central
Bay platform at Whipray Basin
was stable, remaining in the mid-upper 30s (prior to the weekend). Salinity remained near seasonally normal
concentrations in upstream reaches of Shark
River (Tarpon Bay
platform, where salinity is nearly fresh, under 1 psu.
Wildlife
The Fish and Wildlife Conservation
Commission reported that a large percentage of the deer populations of WCA 3A, Holey Land
and Rotenberger have dispersed to the levees. They have observed 200 or so deer on the L5
levee alone. While FWC lacks good
population estimates of the total deer population, they believe that the total
deer population is less than 1000 animals.
Health of the deer appears to be declining; the numbers of dead deer are
increasing, and the bucks are shedding their antlers early. Another species that appears to be highly
stressed is marsh rabbits. Large numbers
of dead marsh rabbits are being found in WCA-3A.
Water Supply
Water levels generally
declined slightly across most of the District, although there were some areas
of localized variability. Water levels
in the upper and lower Kissimmee
Basin are now near or
slightly below their average conditions for their respective periods of
record. Water levels in the Lower West
Coast are mostly above their historical averages although wells in the upper Caloosahatchee River Basin are now below their historic
conditions. Water levels in the Lower East Coast are now near or slightly below their
historical averages. Water levels in the
Upper East Coast remain above their historic
averages and are close to their highest recorded values. Surface and groundwater levels in Water
Conservation Areas 1, 2 and 3 continue to remain above their historic averages
this week – the highest recorded levels were within Water Conservation Areas 2
and 3.
All 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 and LEC Service Areas 1, 2 and 3 (as a result of the
removal of water restrictions) are now in the “low” risk category.
LORS2008 (Lake Okeechobee Regulation Schedule)
Stages in Lake
Okeechobee are within one foot of the intermediate band, and
tributary conditions are wet, which calls for discharges of up to 3000 cfs at S-79 and up to 1170 cfs at
S-80, and maximum practical discharges to the south if desired or with minimal
impact. The United States Army Corps of
Engineers (USACE) initiated a second pulse release on September 16th,
with an overall release average of 3000 cfs at S-77
and 1500 cfs at S-80.
CC: George Horne
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