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
21, 2008
SUBJECT: Weekly
Environmental Conditions for Systems Operations
Summary
Floodplain depths in the
restored area of the Kissimmee River continue to decrease and Lake Okeechobee (
On October 14th,
the United States Army Corps of Engineers (USACE) initiated baseflow
releases to both estuaries, with an overall average release of 450 cfs at S-79 to the
Background
Potential for
heavy rains on Thursday and Friday. A weak
post-frontal trough is across central
Over the last seven days, the
upper Kissimmee Basin received 0.34 inches of rainfall to bring the 30 day total
to 3.93 inches (98% of average) and the lower basin received approximately 0.16
inches to bring the 30 day total to 4.2 inches (108% of average).
Water levels in the upper
basin lakes continue to closely follow their regulation schedules. The stage in Lakes Kissimmee, Hatchineha and
Discharge from
Large numbers of wading birds
are foraging on the floodplain.
From 10/14/08 to 10/21/08
dissolved oxygen (DO) concentrations in the
According to the Unites
States Army Corp of Engineers (USACE) web site,
Monthly submerged aquatic
vegetation (SAV) sampling was conducted along the southern shoreline last
week. A continued decline in Chara was reported, with sparse growth reported at 1
of 7 sites. Water clarity remains poor,
with secchi depths < 0.5 m and secchi
depth:total depth ratios
< 0.2.
Vegetation management crews
are on the
A survey will be conducted
this week to determine the status of large numbers of the endangered Okeechobee
Gourd that became established on the southern islands during the drought.
St. Lucie Estuary
During the last week, an
average discharge of 210 cfs
occurred at S-80 from C-44 including 185 cfs at S-308
from the Lake, 188 cfs at S-97 from C-23, and 207 cfs 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 |
|
0.77 (0.46) |
0.83
(0.56) |
|
HR1 (N. Fork) |
1.66 (2.20) |
4.30 (4.79) |
|
|
4.41 (3.26) |
5.52 (3.83) |
8.0 – 25.0 |
A1A Bridge |
16.32
(10.85) |
23.90 (20.18) |
20.0 – 31.0 |
Compared with the previous
week, average salinity increased from < 1 ppt in
Caloosahatchee Estuary
During the last week, an
average discharge of 915 cfs occurred at S-79, 197 cfs at S-78, and 43 cfs at
S-77. The concentration of chlorides at
the Olga Plant was 53 ppm on Monday, up from 46 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 |
|
0.26 (0.24) |
0.27
(0.25) |
Rt. 31 Bridge |
0.27
(0.24) |
0.28
(0.25) |
I-75 Bridge |
0.31
(0.26) |
0.36
(0.27) |
|
1.19 (0.29) |
2.93 (0.30) |
|
6.78 (3.10) |
10.03 (5.71) |
Shell Point |
21.36 (16.61) |
22.48 (20.12) |
In the estuary, freshwater
conditions extend from S-79 downstream to
Compared with the previous
week, average salinity remained about the same in the upper estuary to
I-75. An increase in salinity of 1-2.5 ppt occurred at
Fish and Wildlife
Research Institute (FWRI) reports that background
concentrations of Karenia brevis, the Florida
red tide organism, were detected this week in water samples collected at the Gasparilla Fishing Pier (Charlotte County), South Seas
Plantation (Captiva, Lee County) and Lovers Key State
Park (Lee County). All other water
samples collected alongshore between Pinellas and Collier counties contained no
K. brevis.
A bloom of K. brevis, identified last
week west of
Water Conservation
Areas
Stage changes
declined throughout the Greater Everglades (GE). The greatest drop in stage occurred in WCA-2A
(-0.32’) and the least in WCA-1 (-0.05’).
Average basin stage changes are listed below:
Change: WCA-1: -0.05
ft WCA-3A: -0.20 ft
WCA-2A: -0.32 ft WCA-3B: -0.10
ft
WCA-2B: -0.16
ft NESRS: -0.19 ft
Stages in WCA-1
are slightly below regulation depths.
WCA-2A stages are declining but are still above their regulation stage,
as they have been for more than one full year.
The stage in WCA-3A has stabilized at last week’s level and remains over
a foot above regulation, continuing an exceedance
that began in mid-July. With the end of
the rainy season, we expect stages to drop gradually as evapotranspiration
exceeds rainfall.
Water depths in
the Greater Everglades are now below 4 feet at all gauges, and depths at two
gauges (EDEN-13 in WCA-2B and Site 62 in WCA-3A) have dropped below 2.5 fee, the general threshold for tree islands. Parts of WCA-1, -2, -3A, and 3B are still
above this threshold. So far none of
these regions have exceeded the 120 day maximum duration for tree islands. The two gauges with the longest inundation
periods are the ponded region of WCA-2B at 98 days
and southern WCA-3A at 84 days.
Light to moderate rainfall
accumulations were measured last week (from Sunday to Sunday) across Everglades
National Park (ENP) and
Stages in ENP wetland areas
declined for the week. Several areas,
including Shark River Slough, Craighead Pond, and the ENP panhandle, dropped by
approximately 1 inch over the seven day period.
Stages at
Salinity dropped or remained
stable across
Water Supply
Water levels in the upper and
lower
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
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. The LOK Seasonal Net Inflow Forecast has
turned from “low” to “medium” risk, on the anticipation of the coming dry
season.
LORS2008 (
Stages in Lake Okeechobee (
CC: George Horne