MEMORANDUM
TO: Chip
Merriam, Deputy Executive Director, Water Resources
FROM: SFWMD Staff Environmental Advisory Team
DATE: November 20, 2007
SUBJECT: Weekly
Environmental Recommendation for Systems Operations
Recommendation
No Lake Okeechobee regulatory releases to the
south or estuaries are recommended.
Background
Scattered showers this weekend. Northeast to east winds will bring widely
scattered light showers east today. As
high pressure currently near
Over the last seven days, the upper Kissimmee Basin
received 0 inches of rainfall to bring the 30 day total to 2.17 inches (83% of
the long-term average) and the lower basin received 0 inches to bring the 30
day total to 1.65 inches (69% of the long term average). During the last week, water levels in most of
the upper basin lakes decreased slightly or remained steady. Water levels in
Flow has been reestablished to the
According
to the USACE web site,
Near
shore areas of the lake continue to experience moderate turbidity in response
to windy conditions. Beds of the macroalga Chara are declining in offshore areas on the south
side but appear to be stable closer to shore. Beds of the vascular
species eelgrass (Vallisneria
St. Lucie Estuary
There were no releases through S-80 over the past
week. Discharge at S-97 on the C-24
Canal is currently 0 cfs. Discharges at S-49 on the C-23 canal are
currently about 4 cfs. 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 |
|
4.28 (2.5) |
5.69 (2.9) |
|
HR1 (N. Fork) |
8.06 (7.3) |
11.02 (10.3) |
|
|
11.04 (9.7) |
12.34 (12.1) |
8.0 – 25.0 |
A1A Bridge |
18.40 (17.9) |
24.34 (24.4) |
20.0 – 31.0 |
Salinity conditions improved this week throughout
the estuary. Both the surface and bottom
salinity are now up to the preferred range at the
Caloosahatchee Estuary
No discharge occurred at S-79 last week. The concentration of chlorides at the Olga
Plant is 144 mg/l. Average salinity
increased throughout the estuary last week.
Weekly average salinities for specific sites are given below in parts
per thousand (ppt).
Current weekly averages (in bold) may be compared to last week’s data
(in parenthesis).
|
Weekly Average Salinity (ppt) |
|
Sampling Site |
Surface |
Bottom |
|
13.3 (10.9) |
14.0 (12.3) |
Rt. 31 Bridge |
12.0 (10.2) |
14.0 (13.7) |
I-75 Bridge |
12.0 (10.5) |
14.6 (14.2) |
|
17.1 (15.4) |
18.4 (17.1) |
|
22.8 (22.3) |
25.1 (24.5) |
Shell Point |
30.3 (30.0) |
31.5 (30.9) |
Salinity conditions throughout the system remain
good seaward of
FWRI reports that water samples collected offshore this week, 7 to 25 miles
west of
Water Conservation Areas
Rainfall throughout the WCAs was negligible (i.e., 0.08” – 0.02”). Average
precipitation for the Greater Everglades was only 0.04 inch. This was another
week with a deficit water budget because ET was 1.11
Dry season recession rates now predominate
the entire region but not as much as they did last week. Water depths decreased
by 0.15’ in WCA-1, 0.12’ in WCA-2A,
0.16’ in northern WCA-3A, 0.11’ NESRS,
but only by 0.04’ in WCA-3B and central WCA-3A. Water depths are typically between
2-3 ft, at this time of year, in the WCAs.
However, WCA-1, 2A and WCA-3A
are just barely above 2.0 ft. In northern WCA-3A,
where drought impacts are expected to be severe this spring, the depths are
similar to the drought of last year and about 1.25 ft less than in 2005.
However, the wet season depths last year were greater and provided for better
fish habitat. Therefore, wading bird prey populations will likely be worse than
they were last year.
Stages in WCA-1 are about to enter
within Zone B, WCA-2A remains well above regulation,
and stages in WCA-3 remain below regulation.
ENP wetland water levels declined last week. Water level at Shark
River Slough (P33) was down by 0.2”, but remains low for this time of
year. To the south, water levels declined by 1.2 and 2.3” at Craighead
Pond and EVER6, respectively, and
Salinity
managed to concurrently increase, decrease, and/or remain stable across FL Bay
last week. At Trout Creek, salinity was quite variable throughout the
week, flashing (almost daily) from single digits up to the low 20s, but
ultimately increasing to near 25 psu by week’s
end. A similar trend occurred at
Water Supply
Water
levels in the upper and lower Kissimmee Basin and Lower West Coast declined
slightly this week – and are now slightly below their historical average
conditions for this time of year. Water levels in the coastal areas of
The
Water Supply Risk Measures were unchanged this week. Six out of eleven
water supply risk measures are in the “high” risk category - the projected Lake
O Stage (SSM), the Palmer Index for Tributary
Conditions, the LOK Seasonal Net Inflow Forecast 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
CPC Precipitation Outlook and Multi-Seasonal Net Inflow Forecasts remain at
“medium” risk this week.
WSE
(
The current
CC: George
Horne