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: January
20, 2009
SUBJECT: Weekly
Environmental Conditions for Systems Operations
Summary
Discharge from
On December 15, 2008, the
United States Army Corps of Engineers (USACE) discontinued base flows to the Saint
Lucie estuary and increased flows to the Caloosahatchee Estuary to 650 cfs. Today the USACE initiate a seven day pulse
release to the Caloosahatchee Estuary that will average 650 cfs over the seven
days.
Background
Freezing temperatures likely over the
Over the last
seven days, the upper Kissimmee Basin received 0.25 inches of rainfall to bring
the 30 day total to 0.45 inches (19% of average) and the lower Kissimmee Basin
received 0.23 inches of rain to bring the 30 day total to 0.41inches (23% of
average).
Stage in Lakes
Kissimmee, Hatchineha and
The final treatment of
hydrilla with Aquathol on
Surveys last week confirmed
that some of this hydrilla is likely to die soon and that additional treatments
are not warranted in all areas of the plot. The updated treatment area is immediately
south of Brown’s Point and does not include the deeper portions of the littoral
zone.
Snail kite courtship and
nesting behaviors are beginning to be observed around
Discharge from
Some shoaling has
been observed within the river channel in the northern portion of the restored
area. Care should be taken when
navigating through this area.
The dry season
drawdown of the Pool B/C area is on track to reach a low stage target of 33
feet on or around May 15, 2009.
Wading bird
activity observed during aerial surveys last Tuesday was average except near
the active construction area. One large
flock of white ibis and some smaller mixed species flocks were observed on the
west side of the construction area within flooded wet prairie.
Dissolved oxygen (DO)
concentrations in the
According to the USACE web
site,
December water-quality monitoring results are now available. All 25 monitoring stations had sufficient
water for sampling. Total phosphorous averaged 152 ppb lakewide
(compared to 225 ppb in November) and 139 ppb
at nearshore stations (compared to 177 ppb in November). Total suspended solids (TSS) averaged 21 ppm lakewide (compared to 67 ppm in November) and 16 ppm at nearshore stations (compared to
27 ppm in November.
Last week, transect sites along the western shoreline were sampled
for submerged-aquatic-vegetation (SAV) to complete the monthly survey. A total of 37 sites were sampled this month
(five in the south, 25 in the north, seven in the west) and plants were found
at 23 of those sites (zero in the south, 20 in the north, three in the west). Last month 24 sites were visited and only
eight had plants. The increase in the number of sites with
plants this month was due in part to being able to access more of the innermost
sites in the north where plants are starting to colonize in areas that were dry
before Tropical Storm Fay. The innermost
sites in the south and west are still too terrestrial to sample.
Monthly phytoplankton
monitoring was performed at eight of the nine sites last Wednesday (January 14th)
and no blooms were observed. Mean secchi
depth was 0.46 m (compared to 0.44 m in December) with greatest depths near the
mouth of the
Saint Lucie Estuary
Over the past week discharge
averaged 0 cfs at S-80. Discharge from the
|
Weekly
Average Salinity (ppt) |
|
|
Sampling
Site |
Surface |
Bottom |
Envelope |
|
12.2
(11.9) |
14.0
(13.9) |
|
HR1
(N. Fork) |
NR (14.7) |
NR
(18.1) |
|
|
21.7 (19.7) |
22.1 (20.4) |
8.0
– 25.0 |
A1A
Bridge |
29.6 (27.2) |
30.6
(28.6) |
20.0
– 31.0 |
Salinity increased throughout
the estuary during the past week. Salinity
at
Caloosahatchee Estuary
During the last week,
discharge averaged 652 cfs at S-79, 474 cfs at
S-78, and 695 cfs at S-77. The
concentration of chlorides at the Olga Plant was 69
ppm yesterday. 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).
|
Weekly
Average Salinity (ppt) |
|
Sampling
Site |
Surface |
Bottom |
|
2.5
(3.4) |
2.5 (3.6) |
Rt.
31 Bridge |
3.1
(4.0) |
3.1 (4.1) |
I-75
Bridge |
3.6 (4.5) |
4.9 (6.4) |
|
8.6
(11.5) |
10.4
(12.8) |
|
18.6
(19.7) |
19.1
(20.5) |
Shell
Point |
26.6
(29.5) |
28.8
(31.2) |
Salinity declined over the
past week. Conditions in the upper
estuary east of
Fish and Wildlife
Research Institute (FWRI) reports that water samples
collected alongshore between Pinellas and Monroe counties contained no K. brevis. Monitoring data collected by the River,
Estuary and Coastal Observing Network (RECON) of Sanibel-Captiva Conservation
Foundation (SCCF) indicated that over the last week Chlorophyll concentrations
ranged between 2.5 and 8.1µg/L at
Water Conservation
Areas
Stages in all
basins continue to decline at rates considered good for wading bird feeding and
support of chicks. Southern WCA-3A
depths are still above 2.5 inches (175 days), still stressing tree islands, but
water levels are declining. Average
weekly basin stage declines were:
Stage Change: WCA-1: - 0.07 foot WCA-3A: - 0.08 foot
WCA-2A: - 0.09 foot WCA-3B: - 0.06 foot
WCA-2B: -
0.09 foot NESRS: - 0.10 foot
Depths at gauges
range from 0.40 foot in WCA-2A to 3.52 feet in WCA-2B, but most gauges report
depths of one foot to a bit over two feet.
Local changes in water depths can be seen in the depth contours
maps. Areas of dryout are expanding with
declining water levels in the northern areas of the water conservation areas,
in Everglades National Park (ENP), and in Big Cypress Preserve. The deep water north and west of the L-67
canals is declining as well. Compartmentalization
has led to annual drying that proceeds from the north to the south. In the original system, peat rarely dried
out. Peat must remain hydrated to
accumulate and to avoid loss through oxidation.
Continuing recent
trends, WCAs 1 and 3 remain below the Regulation Schedule, while WCA-2 is above
regulation.
Only trace precipitation fell
across ENP and
Stages continued to decline
in ENP last week. Water levels in Shark
River Slough (P33) and at the
Salinity was stable or declined
in
Water Supply
Water levels across the
District continued to decline over the past week. Many Floridan aquifer wells in the
In the Lower West Coast area,
groundwater wells are showing seasonal declines in water levels in the
Surficial,
Water supply risk indicators
are in the “low” risk category including the projected LOK Stage, the Water
Conservation Areas 1 and 3A, and LEC Service Areas 1, 2, and 3 (no
restrictions).
The CPC Precipitation
Outlook, the LOK Seasonal Net Inflow Forecast, the LOK Multi-Seasonal Net
Inflow Forecast, the Palmer Index for LOK Tributary Conditions, and Water
Conservation Area 2A continue in the “medium” risk category.
LORS2008 (
Stages in
On December 15, 2008, USACE discontinued
base flows to the St. Lucie Estuary and increased flows to the Caloosahatchee
Estuary to 650 cfs. Today the USACE
initiate a seven day pulse release to the Caloosahatchee Estuary that will
average 650 cfs over the seven day period.
The District recommends that the USACE initiate another seven day 650
pulse release to the Caloosahatchee Estuary when the current one is completed.