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: July
24, 2007
SUBJECT: Weekly
Environmental Recommendation for Systems Operations
Recommendation
No regulatory releases to the south or estuaries are recommended.
Background
Above average rain days
continue. A deep layered trough extends
from an anchoring low over West Virginia
through the Gulf of Mexico. The resultant upper level wind field is
considerably more energetic than we normally see in late July. So, a typically quiet/drier stage in the wet
season has been displaced this year.
Look for heavy showers/storms to yield a general focus north through
southeast of the Lake this afternoon/early
evening. Steering winds become light
tomorrow, and this should translate into a focus of storms over the interior
south. Steering winds become more
easterly on Thursday to probably provide some focus west of the Lake. Rainfall may
decrease to near average by Friday, but more changes on Saturday suggest an
increase in rains again over the weekend. The next ten days precipitation outlook is average
with moderate confidence.
Kissimmee Watershed
The upper Kissimmee Basin received 3.14
inches of rainfall over the last 7 days to bring the total for the month to
7.74 inches (159% of average) and the lower basin received 1.93 inches to bring
the total for the month to 8.17 inches (181% of average) (Daily Rainfall Report
for 7/23/07).
Snail kites continue to nest on Lake Tohopekaliga.
No update from last week.
Flow has been reestablished to the Kissimmee River. The river was without inflow from the upper
basin for 252 days (gates at S-61 and S-65 were closed Wednesday 11/8/2006 and
S-65 re-opened on 07/18/07). Some
movement of water began a few days earlier when the S-65A and S-65C structures
were opened.
One week ago, the concentration of dissolved oxygen
had declined to very low levels, but it has recovered fairly quickly as flow
was reestablished. Mean daily values
have been near or above 2 mg/L for several days.
The algal bloom reported last week in
Pool D section of the C-38 has disappeared with increased flow through the
pool.
A small fish kill in Pool D was
reported yesterday (Monday July 23, 2007). Only tilapia was observed
Lake Okeechobee
According to the USACE
web site, Lake Okeechobee stage is 9.09’ NGVD today which is 0.01’ lower than it was a week ago and
0.17’ higher than it was a month ago. Surface inflows are 1696 cfs. and surface outflows are not
reported due to missing S77 and S308 data.
This month’s water quality sampling was limited to
7 pelagic sites and the data are not yet available.
An algal bloom was reported on the north end of the
lake between Taylor
Creek and Nubbin Slough
on Sunday. Rainfall induced nutrient
rich inflows might stimulate more algal blooms, especially near major lake
inflow sites.
St. Lucie Estuary
No releases occurred at S-80 over the past
week. Average salinity was comparable to
last week. At the Roosevelt Bridge
salinity averaged 14.0 ppt on the surface and 15.4 ppt on the bottom.
Corresponding values further downstream at the A1A
Bridge are 23.5 ppt and 28.0 ppt. Salinities at both sites are within the
preferred range (8-25 ppt for the Roosevelt Bridge
and 20-31 ppt for the A1A
Bridge). In the North
Fork at the Harbor Ridge station, salinity averaged 10 ppt on the surface and 14 ppt on
the bottom. In the South Fork, at the Palm City
Bridge, corresponding
values were 9.3 ppt and 11.0 ppt. Salinity conditions are good. Oyster survey results from FWRI indicate that average density of oysters in the St.
Lucie increased from a mean density of 96.2 (+144.4) per meter square in
the fall of 2006 to a mean density of 169.0 (+229.4) per meter square
this past spring.
Caloosahatchee Estuary
Discharge at S-79 averaged 207 cfs
last week. Chloride concentration at the
Olga Plant is presently 95 mg/l. Average
surface salinity did not change appreciably in the upper estuary, with surface
salinity ranging from 5.8 ppt at S-79 to 13.3 ppt at Ft.
Myers. Bottom salinities
ranged from 6.3 ppt at S-79 to 17.1 ppt at Ft.
Myers. Salinity at Shell Point declined considerably
averaging 30.5 ppt on the surface and 33.8 ppt on the bottom.
Salinity remains high in the upper estuary. In the lower estuary and San Carlos Bay
salinity conditions are good.
FWRI reports that
no Karenia brevis,
the Florida
red tide organism, was detected this week in water samples collected alongshore
between Pinellas and Collier counties.
Discolored water due to a bloom of the non-toxic cyanobacteria
Trichodesmium remains possible in portions of
Charlotte, Lee and Collier counties.
Water Conservation Areas
As would be expected with a balanced water budget,
most gauges across the Everglades showed
little change, and in fact, four of the 14 standard measuring sites showed a
decline. The only area with a
significant stage increase was WCA-2B and this was
due to high localized rain. Average
stage increase across the entire system for the week was only 0.04 ft. Depths,
which averaged about 1 ft across the system, are relatively low for this time
of year. In terms of the Regulations
Schedules; WCA-1 is at Regulation, WCA-2A is above Regulation, and WCA-3A
is below regulation.
Everglades National
Park
Water levels were unchanged from last week in the southern part of
Taylor Slough, at Craighead Pond (CP).
Across all other areas of the Park, though, stages declined. In SRS at P33, water level dropped slightly
(by nearly 0.4”). Water level in the Everglades National Park panhandle (at EVER6) saw a decline of 1.2”. Once again Taylor Slough
Bridge saw the largest
weekly change, dropping by nearly 2.5” for the week. The water budget for the southern Everglades was either balanced or negative for yet
another week.
Despite lower water levels, salinity across FL Bay was generally
stable. Salinity at Trout Ck. remained
below 5 psu for another week. The platform at the mouth of Little Madeira
Bay held for a second week near 20 psu. Salinity in the TR
ponds was very low all week at ~ 1 psu at Pond 5 and
Argyle Hendry. The 30 d moving average
concentration at TR continues to slowly decline,
remaining well below the 30 psu point (at 0.8 psu as of Sunday 7/22).
Salinity concentrations held steady again this week in the north-central
Bay area of McCormick
Ck. & Terrapin Bay at or near 20 psu. In the central Bay, Whipray Basin salinity remained near 35 psu for yet another week.
To the north and west, Tarpon
Bay (SRS outlflow) salinity stayed low at just below 2 psu as of Sunday, 7/22.
Water Supply
Water levels in the Lower West
Coast continue to remain near low levels for their periods of
record, although rebound continues to occur in the coastal areas of the Upper
and Lower East Coasts and Water Conservation Area 1 as a result of local
rainfall.
Five out of eleven water supply risk measures are
in the “high” risk category this week. The projected Lake O Stage (SSM), the LOK Multi-Seasonal Net
Inflow Forecast and Lower East Coast Service Areas 1, 2 and 3 are all in the
high risk category.
Water Conservation Areas 1, 2A and 3A are now in
the low risk category. The Palmer Index
for Tributary Conditions are now at medium risk.
The CPC Precipitation Outlook remained at “low” risk this week, along with the LOK Seasonal Net Inflow forecasts.
Regarding “Utilities of Concern”, the water supply
dept. has reduced the reporting frequency of most systems from weekly to
monthly, in response to improved wet season conditions
WSE
(Lake Okeechobee Regulation Schedule)
The current Lake O
stage – at 9.07’ today - remains in the Water Shortage Management zone and is
unlikely to move back into Zone E in the next two months.
CC: George
Horne