MEMORANDUM

 

TO:            Chip Merriam, Deputy Executive Director, Water Resources

 

FROM:      SFWMD Staff Environmental Advisory Team

 

DATE:       October 30, 2007

 

SUBJECT: Weekly Environmental Recommendation for Systems Operations

 

Recommendation

 

No regulatory releases to the south or estuaries are recommended.

 

Background

 

Windy with numerous showers and locally heavy rains to 4" near the east coast through tomorrow.  Tropical Storm Noel has pushed inland over eastern Cuba and is expected to turn northwest before exiting off the north coast tonight or early tomorrow.  Regardless, the most significant wind and rain will be east of the center and likely remain east of the District even if the center strays closer to our coast than the official forecast indicates.  That being stated, strong winds and numerous showers will continue to feed across mainly eastern sections of the District with locally heavy rain near the coast through tomorrow.  As Noel exits northeast, rains will end Thursday before dry and pleasant conditions arrive the end of the week.  The next ten days precipitation outlook is near average with moderate confidence.

 

Kissimmee Watershed

 

Over the last 7 days, the upper Kissimmee Basin received 0.13 inches of rainfall and the lower basin received 0.13 inches (Daily Rainfall Report for 10/29/07).  For the last week, water levels have risen slightly in most of the upper basin lakes.  Four lakes (Hart, East Tohopekaliga, Tohopekaliga, and Gentry) are approaching the high pool (maximum allowed) in the regulation schedule.  The only releases being made in the upper basin are at S-65.

 

Flow has been reestablished to the Kissimmee River for 104 days (S-65 re-opened on 07/18/07).  Discharge at S-65 continues at approximately 500 cfs.  In the river channel of the Kissimmee River, mean daily concentrations of dissolved oxygen have been from 2 mg/L to 4 mg/L.

 

Lake Okeechobee

 

According to the USACE web site, Lake Okeechobee stage is 10.28’ NGVD, which is 0.06’ higher than a week ago and 0.44’ higher than a month ago.  The current stage is 2.39’ lower than it was a year ago and remains almost 5’ below its historical average for this time of year.  Total reported surface inflows are 1249 cfs and include discharges through the S65E (1154 cfs) and S191 (95 cfs) structures.  This total does not include gravity flows that might be occurring from WCA1 or through the S77 and S308 structures.  No surface outflows are reported.

 

The monthly submerged-aquatic-vegetation (SAV) survey was completed during the first week of October.  Average SAV biomass increased from 6.42 g dw/m2 in September to 9.1 g dw/m2 this month.  The macroalga Chara is still the dominant species but the vascular plant Vallisneria is still being recorded behind King’s Bar in the North and in FishEating Bay on the west side.  Water clarity remains excellent at nearshore sites but is beginning to decline at offshore sites.

 

St. Lucie Estuary

 

No releases occurred at S-80 over the past week.  The C-24 canal is discharging about 265 cfs at S-97.  Discharge at S-49 on the C-23 canal is currently about 470 cfs.  Weekly average salinities at the four monitoring sites in the St. Lucie are given below in parts per thousand (ppt).

 

 

Weekly Average Salinity (ppt)

 

Sampling Site

Surface

Bottom

Envelope

Palm City Bridge (S. Fork)

2.8

2.9

 

HR1 (N. Fork)

2.0

4.6

 

Roosevelt Bridge

5.8

7.0

8.0 – 25.0

A1A Bridge

16.2

23.0

20.0 – 31.0

 

There was little change in average salinity over the past week.  Only bottom water at the A1A Bridge fell within the preferred salinity range.  Based on the salinity tolerances of the oyster, Crassostrea virginica, salinity conditions in the estuary are poor to fair.

 

Caloosahatchee Estuary

 

Discharge at S-79 averaged 135 cfs over the past week.  The concentration of chlorides at the Olga Plant is 82 mg/l.  Average salinity in the estuary changed little over the past week.  Data for specific sites are given below in parts per thousand (ppt).

 

 

Weekly Average Salinity (ppt)

Sampling Site

Surface

Bottom

Franklin Locks (S-79)

7.6

7.7

Rt. 31 Bridge

7.3

8.3

I-75 Bridge

NA

NA

Ft. Myers Yacht Basin

13.3

13.7

Cape Coral Bridge

21.4

22.6

Shell Point

29.0

30.8

 

Salinity conditions throughout the system are good seaward of Cape Coral.  Conditions in the upper estuary are poor.

 

FWRI reports that offshore samples collected this week detected Karenia brevis, the Florida red tide organism, west of southern Lee and Collier counties. Samples collected 3 to 9 miles west and southwest of Sanibel Island (Lee County) contained K. brevis concentrations ranging from very low to high.  Low to medium concentrations were identified 18 miles west of both Wiggins Pass and Naples and very low concentrations were detected 46 miles west of Naples.  Additional samples collected alongshore of Sanibel Island contained K. brevis concentrations ranging from not present to low with a single fish kill reported from the area.  All other samples collected between Pinellas and Collier counties contained no K. brevis.

 

Water Conservation Areas

 

Water depths rose under 0.1’ with the rainfall in the Everglades except for WCA-2B, where water levels declined slightly (-0.06’).  The decreases that were occurring over the last few weeks at the 2-17 and 62 gages have ceased, rising very slightly.  Water depths at most gages exceed 1.25 feet, but average conservation area depths vary a lot, ranging from 1.3’ in WCA 3B to 3.4’ in WCA 2B.  Stages in WCA-1 are within Zone A2, those in WCA-2A remain well above regulation, and stages in WCA-3 now are just within regulation.

 

Everglades National Park

 

Rainfall was patchy but higher than the previous week across Everglades National Park (ENP) and Florida Bay.  Wetland stations received between 0.8 - 3.4” of rainfall, and marine stations (excluding Taylor River and Whipray Basin) received between 0.6” - 2.5” of rainfall over the 7 day period.  The spatially averaged basin-wide accumulation for last week was 1.0”.

 

Rainfall kept ENP wetland water levels mostly static.  The water level at Shark River Slough (P33) decreased by 0.1” over the 7 day period and remained low for this time of year (end of the rainy season).  Southern stations’ depths increased by 0.6” and 0.8” at Taylor Slough Bridge and the ENP panhandle (EVER6), respectively.  Craighead Pond water level was unchanged last week.  All three of these southeastern Everglades stations had higher water levels than at this time last year.

 

Salinity remained low and stable across Florida Bay last week.  Strong flow from the Everglades down to the Bay through both Trout Creek and Taylor River allowed salinity to remain in the single digits (with a brief mid-week reversal).  Salinity at the Little Madeira Bay mouth platform remained in the low teens last week.  Salinity in the Taylor River ponds remained below 1 psu over the entire week.  In the north-central Bay areas, Terrapin Bay and McCormick Creek salinity decreased slightly to below 11 psu and 8 psu, respectively.  In central Florida Bay, Whipray Basin remained below 30 psu for another week.  In the Shark River Slough outflow at Tarpon Bay, salinity remained low, dropping below 1 psu.

 

Water Supply

 

Water levels generally increased last week, with the exception of the Lower West Coast.  Water levels also rebounded in the coastal areas of Lower East Coast over the past week, and they are now near or slightly above their historical averages.  Surface and groundwater levels in Water Conservation Areas 1 and 2 are now near the historic averages.  Water levels in WCA 3A are still somewhat below their historic averages.  Water levels in the southern-most portion of Dade County are slightly above average historic conditions as a result of local rainfall.

 

Six 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, the LOK Seasonal Net Inflow Forecast and Lower East Coast Service Areas 1, 2 and 3.

 

Water Conservation Areas 1, 2A and 3A continue to be in the “low” risk category.

 

The CPC Precipitation Outlook and the LOK Multi-Seasonal Net Inflow Forecast remain at “medium” risk this week

 

WSE (Lake Okeechobee Regulation Schedule)

 

The current Lake O stage – at 10.28’ today - remains in the Water Shortage Management zone and is unlikely to move back into Zone E in the next several months.

 

 

 

 

CC:   George Horne