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: November
18, 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
Quite
cool Tuesday and Wednesday before a warming trend begins on Thursday. A strong, dry cold front will swing quickly
through the District on Tuesday. Look
for associated winds to kick up and temperatures to begin declining Tuesday
afternoon. Tuesday night will be breezy
and cold with some record lows possible north through west of
Over the last seven days, the
upper Kissimmee Basin received 0.50 inches of rainfall to bring the 30 day
total to 1.35 inches (53% of average) and the lower basin received
approximately 0.10 inches to bring the 30 day total to 0.80 inches (33% of
average).
Stage in Lakes Kissimmee, Hatchineha and
Discharge from
Water depths on the
floodplain currently range from 0.5 to 1.0 foot in the south end of the
restoration area and in low-lying areas.
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 onto the floodplain around the active
backfilling in an effort to control turbidity. The contractor expects to widen/clean out the
flow-way around the construction area and decrease the head difference soon.
The post-Tropical Storm Fay
recession rate on the floodplain is approximately 2.2 feet/30 days, about twice
as fast as our target rate.
From 11/4/08 to 11/18/08
dissolved oxygen concentrations in the
According to the Unites
States Army Corp of Engineers (USACE),
The monthly
submerged-aquatic-vegetation (SAV) survey was completed during the first week
of November and 10 of the 30 sites sampled had plants (compared to 16 of 35 in
October). The macroalga
Chara has declined in coverage at the
south end of the lake and has disappeared from
October
water-quality monitoring results are now available. All 25 monitoring stations had sufficient
water for sampling. Total phosphorus
averaged 155 ppb lakewide (compared to 128 ppb in
September) and 138 ppb at nearshore stations (compared
to 118 ppb in September). Total
suspended solids averaged 25 ppm lakewide (compared to 20 ppm in September) and 12 ppm at nearshore
stations (compared to 11 ppm in September).
October phytoplankton
monitoring was completed at 7 of the 9 sites and results are now available. Chlorophyll a concentrations averaged 12
ppb and ranged between 3 ppb (
Last week crews surveyed the
recently flooded scraped areas at
St. Lucie Estuary
Over the past week discharge
averaged 215 cfs at S-80. Discharge from the
|
Weekly Average Salinity
(ppt) |
|
|
Sampling Site |
Surface |
Bottom |
Envelope |
|
5.31 (3.35) |
6.61 (5.41) |
|
HR1 ( |
11.27 (9.76) |
12.58 (15.38) |
|
|
12.68 (11.82) |
14.06 (14.98) |
8.0 – 25.0 |
A1A Bridge |
22.68
(18.66) |
25.09 (24.44) |
20.0 – 31.0 |
Salinity increased throughout
the estuary with a slight decrease in bottom salinities at HR1 and the
Caloosahatchee Estuary
During the last week,
discharge averaged 433 cfs at S-79, 253 cfs at S-78, and 333 cfs at S-77. The concentration of chlorides at the Olga
Plant was 65 ppm Monday. 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 |
|
4.34 (4.31)
|
4.33
(4.47) |
Route 31 Bridge |
5.14(3.70)
|
5.46
(5.95) |
I-75 Bridge |
5.58
(3.30) |
6.59
(9.41) |
|
9.44 (6.18)
|
9.65 (13.72)
|
|
17.05 (12.77)
|
17.80 (16.24)
|
Shell Point |
27.97 (23.53)
|
27.50 (24.14)
|
Salinity increased throughout
the estuary except for bottom salinities above
Fish and Wildlife
Research Institute (FWRI) reports that water samples
collected alongshore between Pinellas and Collier counties contained no red
tide organism, Karenia brevis. Additional samples, collected offshore of
Sanibel Island in
Water Conservation
Areas
Stage dropped
significantly over the last two weeks everywhere due to evapotranspiration
and structure openings. Average basin
weekly stage changes for the week ending on 11-18-08 were:
Stage Change: WCA-1: -0.15 foot WCA-3A: -0.20
foot
WCA-2A: -0.28 foot WCA-3B: -0.10 foot
WCA-2B: -0.13
foot NESRS: -0.08 foot
The Everglades
Protection Area is still at a seasonal high, in terms of depths. The southern
region of WCA-3A has 3.42 feet of water and is now 112 days above the tree
island threshold of 2.5 feet. The
northern region of WCA-3A at gage 63 has 2.43 feet of water and is no longer above
the tree island threshold. Other high
depth regions include: 2B, central 3A, and northern 3B. So far, none of these regions have exceeded
the 120 day maximum duration for tree islands. With the end of the rainy season, stages are
expected to drop gradually to 2.5 feet or below, except in southern WCA-3A,
before tree islands are expected to experience flooding stress.
Stages in WCA-1
are within the A1 regulation depths. WCA-2A
stage has dropped some two feet in the last two months and is only slightly
above regulation stage. Thirteen months
above regulation in WCA-2A is about to come to an end. The stage in WCA-3A is
about 0.5 foot above regulation, continuing an exceedance
that began in mid-July.
Stages in Everglades National
Park (ENP) declined last week. Water
levels in Shark River Slough and the ENP panhandle decreased by 0.5 inches and
0.4 inches, respectively. In southern
Taylor Slough, water levels at the
Salinity remained mostly
steady in
Water Supply
Water levels declined
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 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
the highest recorded levels were within Water
Conservation Areas 1 and 2. Water levels
in the area of
Ten 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 Multi-seasonal Net Inflow Forecast, and Water Conservation Areas 1,
2A and 3A. The projected Lake Okeechobee
Stage and Lower East Coast Service Areas 1, 2 and 3 (as a result of the removal
of water restrictions) are now in the “low” risk category. The Lake Okeechobee Seasonal Net Inflow
Forecast remains at “medium” risk in advance of the upcoming dry season
LORS2008 (
Stages in
CC: George Horne