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: November
4, 2008
SUBJECT: Weekly
Environmental Conditions for Systems Operations
Summary
Water depths on the restored
On October 14th,
the United States Army Corps of Engineers (USACE) initiated baseflow
releases to both estuaries, targeting an overall average release of 450 cfs at
S-79 to the
Background
Mainly
dry and warm through Saturday morning.
Double barreled low pressure systems are developing off the east and
southeast coast of the
Over the last seven days, the
upper Kissimmee Basin received 0.19 inches of rainfall to bring the 30 day
total to 4.02 inches (146% of average) and the lower basin received
approximately 0.10 inches to bring the 30 day total to 3.15 inches (121% of
average).
Stage in Lakes Kissimmee, Hatchineha and
Discharge from
Lake
The post-Tropical
Storm Fay recession rate on the floodplain is approximately 2.4 feet/30 days.
From 10/28/08 to
11/4/08 dissolved oxygen (DO) concentrations in the
According to the Unites
States Army Corp of Engineers (USACE)
Field sampling during the
past week indicates that water-quality and biological conditions are similar to
previous weeks. Water clarity along the
western shoreline remains fair, with secchi depth:total depth ratios of 0.3 to
0.4, and locally dense areas of Vallisneria
persist in the Fisheating Bay-Harney Pond area.
St. Lucie Estuary
Over the past week, discharge
averaged 151 cfs at S-80. Discharge from the
|
Weekly Average Salinity
(ppt) |
|
|
Sampling Site |
Surface |
Bottom |
Envelope |
|
2.21 (2.96) |
2.96 (3.71) |
|
HR1 ( |
9.07 (4.81) |
14.42 (9.49) |
|
|
10.50 (8.30) |
12.99 (10.87) |
8.0 – 25.0 |
A1A Bridge |
19.80 (19.62) |
25.14 (25.78) |
20.0 – 31.0 |
Salinity increased in the
North Fork and at the
Caloosahatchee Estuary
During the last week,
discharge averaged 527 cfs at S-79, 51 cfs at S-78, and 0 cfs at S-77. The concentration of chlorides at the Olga
Plant was 53 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 |
|
0.71 (0.29) |
1.28 (0.55) |
Route 31 Bridge |
1.05 (0.52) |
1.18 (NR) |
I-75 Bridge |
1.18 (0.82) |
2.31 (1.99) |
|
4.05 (4.46) |
6.85 (7.32) |
|
11.95 (11.53) |
13.86 (14.71) |
Shell Point |
23.09 (24.73) |
NR (NR) |
Salinity conditions in the
upper estuary east of
Salinity remained about the
same downstream of
Fish and Wildlife
Research Institute (FWRI) reports that background
concentrations of Karenia brevis, the
Water Conservation
Areas
Rain was very
light throughout the Everglades Protection Area (EPA). The pan evaporation of 1.2 inches was slightly
greater than last week and significantly greater than rainfall, producing a
precipitation deficit for the week. Basin-level rainfall values for the week
ending on 11-04-08 were:
RAIN: WCA-1: 0.09 inches WCA-3A: 0.02
inches
WCA-2A: 0.16 inches WCA-3B: 0.03 inches
WCA-2B: 0.22
inches ENP: 0.03 inches
Stage dropped
significantly from last week everywhere due to evapotranspiration
and structure openings. Average basin
stage changes for the week ending on 11-04-08 were:
Stage Change: WCA-1: -0.11 foot WCA-3A: -0.20
foot
WCA-2A: -0.28 foot WCA-3B: -0.17 foot
WCA-2B: -0.17
foot NESRS: -0.14 foot
The EPA is still
at a seasonal high, in terms of depths. The southern region of WCA-3A has 3.67 feet of
water and is now 98 days above the tree island threshold of 2.5 feet. The central region of WCA-3A has 3.0 feet of
water and is now 84 days above the tree island threshold of 2.5 feet. Other high depth regions include: WCA-1, 2A,
2B, central 3A, and northern 3B. So far,
none of these regions have exceeded the 120 day maximum duration for tree
islands. With the end of the rainy
season, stages are expected to drop gradually to 2.5 feet or below, except in
southern WCA-3A, before tree islands are expected to experience flooding
stress.
Stages in WCA-1
are slightly below regulation depths. WCA-2A stages are declining but are still
above their regulation stage, as they have been for more than one full year. The stage in WCA-3A has stabilized at last
week’s level and remains over a foot above regulation, continuing an exceedance that began in mid-July.
Stages in Everglades National
Park (ENP) were down last week. Water
levels in Shark River Slough, the ENP panhandle, and
Salinity increased,
decreased, or remained stable across
Water Supply
Water levels declined
slightly across most of the District this week, as a result of relatively light
rainfall. Water levels in the upper and
lower Kissimmee Basin (KB) are now near their average conditions for their
respective periods of record. Groundwater
levels in the western portion of the upper KB are generally lower than those in
the eastern portion. Water levels in the
Lower West Coast are mostly well above their historical averages although wells
in the upper
Ten out of the eleven water
supply risk indicator parameters are now in the “low” risk category, including
the CPC Precipitation Outlook, Palmer Index for Tributary Conditions, the Lake
Okeechobee Multi-seasonal Net Inflow Forecast, and Water Conservation Areas 1,
2A and 3A. The projected Lake Okeechobee
Stage and Lower East Cost Service Areas 1, 2 and 3 (as a result of the removal
of water restrictions) are now in the “low” risk category. The Lake Okeechobee Seasonal Net Inflow
Forecast remains at “medium” risk in advance of the upcoming dry season.
LORS2008 (
Stages in
CC: George Horne