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: August 12, 2008
SUBJECT: Weekly
Environmental Recommendation for Systems Operations
Recommendation
No
Lake Okeechobee regulatory releases to
the south or estuaries are recommended.
Background
Below
average rainfall expected. Moisture has
improved over central
Over the last seven days, the
upper Kissimmee Basin received 0.77 inches of rainfall to bring the 30 day
total to 7.29 inches (108% of average), and the lower basin received 1.24
inches to bring the 30 day total to 9.43 inches (152% of average).
Water levels in all of the
upper basin lakes are at or slightly below their regulation schedules. Releases are being made from East Lake Tohopekaliga (290 cfs) and
Water depths on the
floodplain within the restoration project range from approximately 0.4 to 2.3
feet and nearly all of the floodplain is inundated.
From 8/5/08 to 8/12/08 dissolved
oxygen concentrations in the
According to the USACE web
site,
The monthly submerged-aquatic-vegetation (SAV) survey was
completed last week. Thirty-five sites
had sufficient water for sampling, and all but 1 site had water clarity
conducive to plant growth (secchi depth > 50% of
total depth). The macroalga
Chara remains the dominant SAV species and was
found at 20 of the 35 sites.
The vascular SAV species Vallisneria
americana was present 8 of the 22 sites sampled
near the northern and western shorelines but continues to be absent in the
south (13 sites sampled). For the first
time in over a year, the southern naiad (Najas
guadalupensis) was found in very low density in the northern region (
The
comprehensive annual SAV mapping on
St. Lucie Estuary
There were no releases
through S-80 from C-44 over the past week. An average discharge of 121 cfs through S-48 from
C-23 and 220 cfs through S-49 from C-24 occurred 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).
|
Weekly Average Salinity
(ppt) |
|
|
Sampling Site |
Surface |
Bottom |
Envelope |
|
5.78 (5.08) |
7.68
(6.01) |
|
HR1 (N. Fork) |
5.62 (4.60) |
11.08 (9.66) |
|
|
9.03 (7.80) |
12.57 (10.32) |
8.0 – 25.0 |
A1A Bridge |
18.88
(16.63) |
24.87
(22.76) |
20.0 – 31.0 |
Compared with salinities of
the previous week, average salinity in the estuary increased about 0.7 to 2.8 ppt. Three of four
monitoring stations are reporting salinities within the preferred range. Salinity conditions in the estuary are
considered to be fair to good based on the salinity preference of the oyster, Crassostrea virginica, and
location in the estuary.
Caloosahatchee Estuary
An average weekly discharge
of 1003 cfs occurred
at S-79. The concentration of chlorides
at the Olga Plant was 56 ppm yesterday, down from 64 ppm in 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).
Based on the USGS flow meter
located just below S-77 water is flowing back into the
|
Weekly Average Salinity
(ppt) |
|
Sampling Site |
Surface |
Bottom |
|
0.25 (0.29) |
0.25 (0.29) |
Rt. 31 Bridge |
0.27
(0.30) |
NR (NR) |
I-75 Bridge |
0.34
(0.40) |
0.30
(0.39) |
|
1.07 (0.85) |
1.49 (0.86) |
|
NR (7.78) |
NR (9.54) |
Shell Point |
21.15
(22.88) |
22.54 (24.41) |
In the estuary,
freshwater extends from S-79 downstream, at least to
Salinity at
No Karenia brevis, the
Water Conservation
Areas
In spite of this
net deficit, rehydration rates were good to fair over
most of the
Water depths at
the gages are generally higher than depths a few weeks ago. These depths range from 1.05’ in WCA-1 to
3.15’ in WCA-2B. WCA-3A depths range
from 1.6’ to 2.6’.
Stages are just
below regulation in WCA-1, slightly above regulation in WCA-3A, but remain well
above regulation in WCA-2A.
Rainfall totals were moderate
last week across Everglades National Park (ENP) and
Stages in ENP wetlands increased
last week. The water level was up by
1.2” last week in Shark River Slough (station P33). To the south, water level increased by approx.
2” and 3.25” in Craighead Pond (southern Taylor Slough) and the panhandle
(station EVER6), respectively. Data discrepancies
from
Salinity trends across
Water Supply
Water levels in the upper and
lower
Water levels in the
There was no change in the
water supply risk indicators since last week.
Seven 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.
Three out the eleven water
supply risk indicators are now in the “medium” risk category, including LEC
Service Areas 1, 2 and 3.
Only one risk measure is now
in the “high” risk category - the projected Lake Okeechobee Stage (
LORS2008 (
The current
CC: George Horne