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: April
21, 2009
SUBJECT: Weekly Environmental Conditions for Systems
Operations
Summary
Discharge from
Water level recession rates are
considered fair or good for wading bird feeding in most of WCA-1 and middle
WCA-3A and -3B. Groundwater levels
continue the current downward trend across most of the District.
Background
Showers ending; becoming warm and dry.
Showers associated with a cold front are exiting the District. Drier air is quickly moving in behind the
front with strong high pressure. This
high will move slowly west to east of the peninsula over the next few
days. Garbage showers could return east
over the weekend, but the next chance for appreciable rain is about ten days
away. The next ten days precipitation
outlook is below average with moderate confidence.
Over the last
seven days, the upper Kissimmee Basin received 0.62 inches of rainfall and the
lower Kissimmee Basin received 0.49 inches (Daily Rainfall Report 4/21/09).
Stages in Lakes
Kissimmee, Hatchineha and
Lakes Tohopekaliga and
Preliminary numbers for the
most recent snail kite nesting survey are as follows:
Discharge from East Lake Tohopekaliga and
A slight turbidity plume
(presumably from the ongoing construction) is visible in lower Pool B/C and
northern Pool D.
Wading bird numbers are low
except around drying pools near the active construction area in northern Pool
B/C.
Discharge at S65C
is about 350 cfs.
Over the last
seven days, dissolved oxygen concentrations in the
According to the United States
Army Corps of Engineers web site,
The monthly
submerged-aquatic-vegetation (SAV) survey was completed last week. A total of 38 sites were sampled this month
(24 in the north, 7 in the west, 7 in the south) and plants were found at 22 of
those sites (18 in the north, 4 in the west, 0 in the south). Two sites were dry (1 in the north and 1 in
the west) and 1 site in the north was too shallow to sample. Last month, 39
sites were visited and 21 had plants. In
the north, numerous dense beds of Vallisneria,
Hydrilla, and Ceratophyllum
were observed. The innermost sites in
the south are still mostly dominated by
cattail and spikerush and too dense to sample effectively although attempts to sample yielded no SAV. All of the sites along the western
wall have dense beds of topped out and reproductive Vallisneria,
so fostering conditions that would allow the lake stage to remain above
10.5 feet would be beneficial to continued SAV expansion.
Monthly
phytoplankton monitoring was performed at eight of the nine sites last week. One site was too shallow to effectively
sample. No blooms were detected at any
of the sites although green flecks were observed in the water column at two of
the northern sites (at the mouth of the
This week, scientists from
the District and Harbor Branch Oceanographic Institute will be tagging
approximately 1,600 juvenile
Saint Lucie Estuary
Over the past week, no
discharge occurred at S-80. Discharge
from the
|
Weekly Average Salinity
(ppt) |
|
|
Sampling Site |
Surface |
Bottom |
Envelope |
|
20.5 (20.7) |
21.5 (21.1) |
|
HR1 ( |
24.8 (23.8) |
25.7 (24.6) |
|
|
27.3 (26.2) |
27.5 (26.5) |
8.0 – 25.0 |
A1A Bridge |
31.6 (30.4) |
33.4 (32.1) |
20.0 – 31.0 |
Salinity throughout the
estuary increased slightly last week. At
both the Roosevelt and A1A Bridges, weekly average salinity is slightly above
the upper bound of the preferred range. Salinity conditions in the estuary are
considered to be fair considering the time of year, the location in the
estuary, and salinity preference of the oyster, Crassostrea
virginica.
Caloosahatchee Estuary
During the past week,
discharge averaged 324 cfs
at S-79, 277 cfs at S-78, and 703 cfs
at S-77. The concentration of chlorides
at the Olga Plant was 129 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 |
|
5.3 (5.5) |
6.4 (6.4) |
Rt. 31 Bridge |
5.3 (7.6) |
7.0 (9.0) |
I-75 Bridge |
6.0 (9.7) |
9.6 (11.4) |
|
14.8 (17.8) |
18.5 (18.6) |
|
24.7 (25.9) |
25.2 (26.9) |
Shell Point |
34.1 (34.2) |
34.5 (35.2) |
The seven day pulse release
at S-79 ended on Friday, 4/17/09. Average salinity decreased slightly throughout
the estuary. Conditions in the upper
estuary east of
Fish and Wildlife
Research Institute reports that water samples collected alongshore between
Pinellas and
Water Conservation
Areas
Water levels are falling at
rates considered Fair or Good for wading bird foraging in WCA-3, but in WCA-1, the rainfall on April 20-21 caused a
general reversal of some 0.10 to 0.20 feet over a single day:
Stage Change: WCA-1: +0.06 foot WCA-3A: -0.01
foot
WCA-2A: -0.00 foot WCA-3B: -0.07
foot
WCA-2B: -0.13 foot NESRS: -0.11 foot
All WCAs are below their regulation schedules.
Despite the recent rains,
water depths continue to be largely below ground in much of the EPA. Water is still available for foraging by
wading birds in WCA-1 and WCA-3A and 3B.
As water depths continue to
decline, there is a loss of peat through decomposition and a higher possibility
of muck fires. Most of the Everglades
Protection Area (EPA) continues to be in the low to moderate muck fire risk
categories.
Very little rain fell across
Everglades National Park (ENP) and
Salinity mostly increased in
Water Supply
Groundwater levels across the
District continue to decline. Floridan aquifer wells in the
Water supply risk indicators in the "low"
risk category include the Water Conservation Area 3A, the Lake Okeechobee (LOK)
Seasonal Net Inflow Forecast and the LOK Multi-Seasonal Net Inflow Forecast. The CPC Precipitation Outlook, the Palmer
Index for LOK Tributary Conditions, and the projected LOK Stage for the next
two months continue in the "medium" risk category. Water Conservation Area 1 has moved into the
"medium' risk category this week as well. The water supply risk indicator for the entire
LEC is in the "medium" risk category, with two days per week watering
restrictions in place except for the utilities at risk. Water Conservation Area 2A remains in the
"high" risk category, with headwater elevation at S11B below Line 2
(9.81 feet).
LORS2008 (
Stages in
On Saturday, April 11, the
Corps initiated a nine-day pulse release to the Caloosahatchee Estuary that
will average 650 cfs per day. Flows from this pulse release ended on
Friday, 4/17.
CC: George Horne