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
28, 2007
SUBJECT: Weekly
Environmental Recommendation for Systems Operations
Recommendation
No
regulatory releases
to the south or estuaries are recommended.
Background
Afternoon
thunderstorms. Steering winds should focus daily activity
over the interior and west today through Wednesday. An upper level trough should increase overall
coverage Thursday and Friday, particularly north. The next ten days precipitation outlook is near
average with low confidence.
The upper Kissimmee Basin received 1.40
inches of rainfall over the last 7 days to bring the 30-day total to 4.91
inches (71% of average) and the lower basin received 0.52 inches to bring the
total for the month to 4.13 inches (66% of average) (Daily Rainfall Report for
08/27/07).
Stages in most of the upper basin lakes have been
stable over the last seven days and are below schedule. The stage in
Snail kites continue to nest on
Flow has been reestablished to the
For the last week, the concentration of dissolved
oxygen in the river channel has remained above thresholds of concern with mean
daily values above 5 mg/L for the previous week
According to the USACE
web site,
This month 21 of the 27 water quality sampling
sites had sufficient water for sampling but only TSS
results are available. TSS values averaged 8
mg/L. In April 07, the last time the
same 21 sites were sampled, mean TSS was 60
mg/L. As reported earlier in the month,
this improved water clarity is associated with a substantial expansion of SAV cover in the nearshore zone
of the lake.
St. Lucie Estuary
No releases occurred at S-80 over the past week. Weekly average salinities at the four
monitoring sites in the St. Lucie are given below in parts per thousand (ppt).
|
Weekly Average Salinity (ppt) |
|
|
Sampling Site |
Surface |
Bottom |
Envelope |
|
2.7 |
3.4 |
|
HR1 (N. Fork) |
3.9 |
7.4 |
|
|
7.8 |
8.9 |
8.0 – 25.0 |
A1A Bridge |
15.5 |
24.3 |
20.0 – 31.0 |
Average weekly salinity in the North and South
Forks declined slightly since the last report. Local freshwater inflow continues to maintain
surface salinity at both the
Caloosahatchee Estuary
During the past week, discharge at S-79 occurred on
two days and averaged 50 cfs for the week. Chloride concentration at the Olga Plant is
presently 82 mg/l. In general, average
salinity at the monitoring sites in the Caloosahatchee Estuary increased over
the past week. Data for specific sites
are given below in parts per thousand (ppt).
|
Weekly Average Salinity (ppt) |
|
Sampling Site |
Surface |
Bottom |
|
8.0 |
9.0 |
Rt. 31 Bridge |
NA |
10.2 |
I-75 Bridge |
7.7 |
11.6 |
|
14.0 * |
NA |
|
19.1 |
20.7 |
Shell Point |
30.5 |
33.0 |
* based on two-day average.
Since surface salinity exceeds 10 ppt at the
FWRI reports that no Karenia brevis, the
Water Conservation Areas
The conservation area gauges reported
rising water stages in the northern conservation areas but falling in the more
southerly ends of WCA-3 and in Everglades National
Park (ENP).
A large fire (“Mack’s Fish Camp South”
fire) of 23,096 acres burned in WCA-3B, merging with
another 3,500 acre fire from the week before.
It was triggered by a lightning strike on Aug. 17 and was declared under
control August 26. Predicted rainfall from
the tropical wave failed to materialize and so the fire continued unchecked.
Water levels decreased at all Everglades National
Park (ENP) platforms last week, likely in part to the
light rainfall pattern and high evapotranspiration
rates. At
Salinity showed mixed trends across
Water Supply
Water levels in the Lower West Coast (LWC) continue to remain near low levels for their periods
of record, and water levels generally decreased in the LWC
over the past week. Water levels
declined slightly in the coastal areas of the Upper East Coast and
There were no changes in the Water Supply Risk
Evaluation metrics between last week and this week. Five out of eleven water supply risk measures
are in the “high” risk category this week including the projected Lake O Stage
(SSM), the Palm Index for Tributary Conditions, and
Lower East Coast Service Areas 1, 2 and 3.
Water Conservation Areas 1, 2A and 3A continue to
be in the low risk category. The LOK Multi-Seasonal Net Inflow Forecast remains at medium
risk this week. The CPC Precipitation
Outlook remains at “low” risk this week, along with the LOK
Seasonal Net Inflow forecast.
WSE
(
The
current
CC: George
Horne