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: October 7, 2008
SUBJECT: Weekly
Environmental Conditions for Systems Operations
Summary
Floodplain depths in the restored
area of the
On September 30th,
the United States Army Corps of Engineers (USACE) initiated a third, 12-day
pulse release, with an overall average release of 2,200 cfs
to the
Conditions in the
Average stage
increases in each of the WCAs ranged from barely
detectable (0.01 foot) in WCA-2B and Northeast Shark River Slough to over 0.5 foot
in WCA-1. Stages in WCA-3A and WCA-3B
rose slightly. Salinity concentrations declined across most of
Background
Showers and storms focus north
again. Not much change is evident from Tuesday,
except stronger low level easterly flow.
Therefore, look for showers and storms to focus east through north of
the
Over the last seven days, the
upper
Water levels in the upper
basin lakes continue to closely follow their regulation schedules except for
Lakes Kissimmee, Hatchineha and
Discharge from
Recent observations revealed
increased numbers of wading birds, waterfowl, migrant shorebirds and migrant
songbirds foraging in and around the floodplain in the restoration area. The post-Fay drawdown is coinciding with peak
migration for many species. Several flocks of migrant blue-winged teal (50-100+
per flock) were observed. Black-bellied
whistling ducks and mottled ducks also were seen. Well over 200 wood storks were mixed with
great egrets, white ibis, snowy egrets, tricolored
herons and little blue herons. At least
one roseate spoonbill and several juvenile wood storks were observed as well. Migrant shorebirds (mostly greater and lesser
yellowlegs, least sandpipers, and spotted sandpipers) were on the floodplain as
well as on newly formed or enhanced sandbars formed from Tropical Storm Fay’s
high flows. Migrant songbirds (mostly
palm warblers, American redstarts, blue-grey gnatcatchers, and other warblers)
were abundant in mixed-species flocks in shrubby areas and along the oak
hammocks foraging on caterpillars. From
9/30/08 to 10/7/08 dissolved oxygen concentrations in the
According to the USACE web
site, Lake Okeechobee (
Generally light algal bloom
activity continues to occur around the
Vegetation management crews
have been active on the lake in recent weeks. The large monoculture of the invasive exotic
plant Luziola previously reported at the mouth
of Fisheating Creek has been successfully treated
with no evidence of regrowth. Another invasive grass, West Indian Marsh
Grass, has greatly increased in coverage since Tropical Storm Fay and is being
treated. Large growths of water hyacinth
and water lettuce have also developed and are being treated.
Spikerush stands that established this past summer along the
lake shoreline continue to persist despite continued high lake stage. Stands along the southern shoreline still
appear healthy, but those along the northwestern shoreline appear stressed,
likely due to a combination of deep water, turbidity, and wave action.
St. Lucie Estuary
During the last week, an
average discharge of 926 cfs occurred at S-80 from
C-44 and 706 cfs at S308, 73 cfs
discharge at S-97 from C-23, and 244 cfs discharge
from S-49 from C-24 (discharge values from S-97 and S49 are provisional). 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 |
|
1.07 (1.14) |
1.86 (2.08) |
|
HR1 ( |
5.65 (4.73) |
10.10 (9.57) |
|
|
7.14 (7.02) |
9.10 (10.30) |
8.0 – 25.0 |
A1A Bridge |
15.16 (16.49) |
21.99 (NR) |
20.0 – 31.0 |
Compared with the previous
week, average salinity remained about the same throughout the estuary. Salinities are close to the lower limit of the
preferred range at
Caloosahatchee Estuary
During the last week, an
average discharge of 3467 cfs occurred at S-79, 1152 cfs at S-78, and 267 cfs at S-77.
The concentration of chlorides at the
Olga Plant was 59 ppm yesterday, up from 53 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 |
|
0.23 (0.22) |
0.24 (0.22) |
Rt. 31 Bridge |
0.23 (0.22) |
0.24 (0.22) |
I-75 Bridge |
0.25 (0.25) |
0.26 (0.26) |
|
0.25 (0.24) |
0.25 (0.24) |
|
1.00 (1.76) |
1.93 (2.57) |
Shell Point |
12.95 (13.30) |
16.92 (17.42) |
In the estuary, freshwater
conditions extend from S-79 downstream to
Compared with the previous
week, average salinity remained about the same throughout the estuary. Salinities at
Fish and Wildlife
Research Institute reports that very low concentrations of
Karenia brevis, the
Water Conservation
Areas
Water levels rose
again with the week’s rainfall. Average
stage changes in each of the
Change: WCA-1: 0.51 ft WCA-3A: 0.08 ft
WCA-2A: 0.09 ft WCA-3B: 0.15
ft
WCA-2B: 0.01
ft NESRS: 0.01 ft
Stages in WCA-1
have risen rapidly this week to just below the regulation depths. WCA-2A stages rose slightly, and are still
above their regulation. This
conservation area has now been above regulation for more than one full year. WCA-3A stage rose slightly again this week
(0.08 foot) and has been above regulation since mid-July.
Water depths at
two gauges in the Greater Everglades range now exceed 4: 4.12 feet in the southern portion of WCA-2B
and 4.03 feet in southern WCA-3A. The
lowest depth recorded at any of the gauges we use is 1.82 feet in central
WCA-1. Large areas of WCA’s 2A and 3B 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, so Inundation Days are now being tracked. The southern region of WCA-3A is now 70 days
above the tree island threshold, the ponded region of
WCA-2B is now 84 days above this threshold, and northern and central areas of
WCA-2B and -3A are 35-56 days into this 120 day period. Efforts to lower stages in central WCA-2A have
kept depths below this threshold for the last two weeks in spite of rainfall
inputs.
Rainfall totals similar to
those in the WCA’s fell across Everglades National
Park (ENP) and
This rainfall increased
stages in ENP wetland areas. Water
levels rose 2.25 – 2.75 inches for the week at several gauges regularly
described in this report (Shark River Slough at P33, ENP panhandle at EVER6,
and Craighead Pond).
Salinity concentrations
declined across most of
Water Supply
Water levels in the upper and
lower
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 (
Stages in Lake Okeechobee (
CC: George Horne