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
3, 2007
SUBJECT: Weekly
Environmental Recommendation for Systems Operations
Recommendation
No regulatory releases to the south or estuaries are recommended.
Background
An active thunderstorm day. An upper level low located off the west coast
of Florida
will bring favorable upper level wind flow to the area today. Some surface convergence also remains across
the District along a trough which extends from a weak low located off the coast
of the Carolinas. Expect daytime heating to generate
thunderstorms focused along bands across south Florida
and across the Kissimmee
Valley. As the upper level low moves south and
southwestward the next couple of days, conditions for thunderstorms will become
less favorable over the southern portion of the District. Therefore expect daily thunderstorm activity
to be focused north and east Tuesday and Wednesday. Thunderstorm coverage will then decrease a
bit Thursday and Friday and be focused over the interior and east. The next ten days precipitation outlook is
near average with low confidence.
Kissimmee Watershed
The upper Kissimmee Basin received 1.32
inches of rainfall over the last 7 days to bring the 30-day total to 5.69
inches (77% of average) and the lower basin received 1.20 inches to bring the
30-day total to 4.08 inches (58% of average) (Daily Rainfall Report for
7/02/07).
The majority of snail kites are
associated with Lake Tohopekaliga and Lake Kissimmee. The most recent surveys include a number of
fledglings. Many active nests, including
some recent nests, are still present on Lake Tohopekaliga.
No water releases are being made at
this time. The Kissimmee
River has lacked flow for 237 days (gates at S-61 and S-65 were
closed Wednesday 11/8/2006).
Concentration of dissolved oxygen in the Phase I restored river channel
has been above thresholds of concern with mean daily values exceeding 3.50
mg/L.
Lake Okeechobee
According to the USACE
web site, Lake Okeechobee stage is 8.82’ NGVD today which is 0.10’ lower than it was a week ago and
0.19’ lower than it was a month ago. Surface inflows are 93 cfs.
and surface outflows are not reported due to missing
S77 and S308 data.
One third of the monthly SAV
sampling is complete and moderate to dense beds of Chara
were observed off of the north west
tip of Ritta
Island and east of Kreamer Island in Pelican
Bay
St. Lucie Estuary
No releases occurred at S-80 over the past week.
At the Roosevelt
Bridge salinity averaged
21.7 ppt on the surface and 22.0 ppt
on the bottom for the week. Corresponding values further downstream at
the A1A Bridge are 28.4 ppt
and 29.3 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).
Caloosahatchee Estuary
Discharge occurred at S-79 on one day over the past
week (weekly average 40 cfs). Chloride
concentration at the Olga Plant is presently 166 mg/l. Weekly average surface salinity ranged from
16.2 ppt at S-79 to 21.6 ppt
at Ft. Myers. Bottom salinities ranged from
18.4 ppt at S-79 to 22.9 ppt
at Ft. Myers. Salinity at Shell Point
averaged 36.4 ppt on the surface and 37.6 ppt on the bottom. Salinity remains high in the upper estuary. In the lower estuary and San Carlos Bay
high salinities are good for seagrass and fair for
oysters.
There have been reports of anoxic bottom water
around the Route 31 Bridge. A
combination of warm temperatures, the deep navigation channel in this area and
stratification of the water column is the likely cause.
FWRI reports that
no Karenia brevis,
the Florida
red tide organism, was detected alongshore this week in samples collected
between Pinellas and Collier counties. Discolored water due to a bloom of
the non-toxic cyanobacteria Trichodesmium
is possible in southern Lee
County.
Water Conservation Areas
The stage increased for most of the Everglades, but not significantly. In WCA-1 depth is
about 0.8 ft, but stage increased by only 0.05 ft for the week. In WCA-2A, the depth is still relatively low at 0.17 ft, but
inundation was good at 0.13 ft. WCA-2B is something
of an enigma where the gage near the canal dropped by 0.11 ft and the interior
site (EDEN-13) increased by 0.26 ft. Enhanced seepage due to urban withdrawals
may be the cause. In the northern sections of WCA-3A
water levels actually dropped by as much as 0.18 ft and the northeastern
section of the region is -0.33 below ground. WCA-3B
had fair re-wetting rates and has an average depth of 0.89 ft, which is good.
The NESRS had a good re-wetting rate this week but is
still relatively shallow for this time of year (depth=0.63 ft). WCA-1 and 3 are below Regulation and WCA-2A
is right at Regulation.
Everglades National
Park
Rainfall was patchy across ENP & FL Bay
again last week, with the panhandle region of ENP
& the Bay proper receiving more rainfall than areas to the north &
west. The range of precip
recorded across the basin (at the stations for which we receive data) was 1.2”
– 5.2” as a 7 d accumulation. This is
not well reflected in the RAINDAR weekly ENP basin-wide spatial average accumulation of 2.0”.
Water levels across the area displayed mixed patterns for another
week. In SRS at P33 and at the Taylor Slough
Bridge, water levels were
down again by ~ 0.75”. In the southern
part of the system, down at Craighead Pond (station CP), water levels did not
change from last week. In contrast, in the panhandle (at EVER6), water levels were up considerably by 2.6”.
Salinity continued to drop or remain low across FL Bay last week.
Salinity at Trout Ck. remained in single digits for much of the week. The platform at the mouth of L. Madeira Bay
read salinity concentrations in the mid-20s, dropping slightly from last week’s
upper 20s. Salinity in the Taylor River
ponds remained < 5 psu all week (~ 3 psu @ Pond 5 & nearly fresh up at Argyle Hendry). The 30 d moving average concentration at TR continues to decline, remaining well below the 30 psu point (at 5.0 psu as of
Sunday, 7/1). Salinity is expected to
remain low in the ponds for the remainder of the wet season. Salinity concentrations held steady in the
north central Bay areas of McCormick Ck. and Terrapin Bay,
into the lower-20s or below 20 psu. In the
central Bay, Whipray
Basin salinity held near
35 psu for yet another week. On a trip taken on
Friday (6/29) the measured salinity was 20 psu in
Garfield Bight. This is well below
average for this time of the wet season (normally salinity is near 30 psu this time of year @ GB), further highlighting the fact
this part of the system has received copious rainfall & flow is making its
way into FL Bay. To the north and west, Tarpon Bay
(SRS outflow) salinity dropped to near 2 psu as of
Sunday, 7/1.
Until the great disparity between the southern and northern rainfall
patterns in the Everglades subsides, we are
not likely to experience an optimistic frame of mind.
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 Upper and Lower East
Coast 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 Palmer
Index for Tributary Conditions and Lower East Coast Service Areas 1, 2 and 3
are all in the high risk category. Water Conservation Areas 1 and 2A are
now in the low risk category. The Lake
Okeechobee Multi-seasonal Net Inflow Forecast and Water Conservation Area
3A stage are now at medium risk.
The CPC Precipitation Outlook remained at “low” risk this week, along
with the LOK Seasonal Net Inflow forecasts.
The chloride concentration at the Olga WTP is at 166 mg/L today.
There was no significant news to report on “Utilities of Concern”
monitored by the Water Supply Department this week.
WSE (Lake Okeechobee Regulation Schedule)
The current Lake O
stage – at 8.82’ 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