MEMORANDUM

 

 

TO:            Chip Merriam, Deputy Executive Director, Water Resources

 

FROM:      SFWMD Staff Environmental Advisory Team

 

DATE:       December 18, 2007

 

SUBJECT: Weekly Environmental Recommendation for Systems Operations

 

Recommendation

 

No Lake Okeechobee regulatory releases to the south or estuaries are recommended.

 

Background

 

Minor showers mainly east through Friday.  Look for warmer temperatures and increasing cloud cover on developing east winds today.  Weak showers could tickle the east coast by evening, but no significant rainfall is expected.  A weak cold front is expected to push through on Friday and again Sunday with only minor rainfall.  Next chance for any appreciable rainfall may arrive in 9-10 days.  The next ten days precipitation outlook is below average with moderate confidence.

 

Kissimmee Watershed

 

During the last week, water levels in all of the upper basin lakes decreased slightly from evapotranspiration.  Water levels in Lakes Kissimmee, Hatchineha and Cypress are approximately 2 feet below regulation schedule.  The only releases being made in the upper basin are at S-65, which is discharging approximately 250 cfs.  Flow has been reestablished to the Kissimmee River for 146 days (S-65 re-opened on 07/18/07).

 

In the river channel of the Kissimmee River, the concentration of dissolved oxygen ranged from 6.3 mg/L – 8.0 mg/L (mean 6.9 mg/L) during the past week.  The slight algal bloom reported last week in Pool D and Pool C has dissipated.

 

Recent wading bird surveys found foraging flocks, dominated by glossy and white ibis, along the receding water line in the upstream portion of the Kissimmee River Restoration Project.  Foraging flocks of wading birds were not observed in the deeper ponded areas near S-65C.

 

Lake Okeechobee

 

According to the USACE web site, Lake Okeechobee stage is 10.24’ NGVD, which is 0.06’ higher than a week ago and 0.07’ lower than a month ago.  The current stage is 1.86’ lower than it was a year ago and 4.58’ below its historical average for this time of year.  Total reported surface inflows have increased from last week and include flows of 424 cfs from the Kissimmee River (S65E), 168 cfs through the S77, and 179 cfs through the L8 at Canal Point.  No outflows are reported.

 

Results of November phytoplankton bloom monitoring show a continued absence of bloom formation.  Seven out of 9 monitoring stations had sufficient water for sampling.  The average chlorophyll concentration was 13 ppb, well below bloom levels (> 40 ppb).  No algal toxins were detected.  Total P concentrations averaged 118 ppb.  These results are similar to those from the past few months.


St. Lucie Estuary

 

There were no releases through S-80 over the past week.  Discharge at S-97 on the C-24 Canal averaged 76 cfs.  Discharge at S-49 on the C-23 canal averaged 52 cfs.  The current weekly average salinities (in bold) at the four monitoring sites in the St. Lucie are given below in parts per thousand (ppt), along with the previous week’s (in parenthesis).

 

 

Weekly Average Salinity (ppt)

 

Sampling Site

Surface

Bottom

Envelope

Palm City Bridge (S. Fork)

4.8 (7.0)

6.1 (9.0)

 

HR1 (N. Fork)

9.9 (11.7)

11.3 (14.4)

 

Roosevelt Bridge

11.9 (14.8)

12.9 (15.7)

8.0 – 25.0

A1A Bridge

20.0 (23.6)

23.5 (26.8)

20.0 – 31.0

 

Salinity decreased this week at all monitoring sites.  Both the surface and bottom salinity are in the preferred range at the Roosevelt Bridge, and at the A1A Bridge.  Based on the salinity tolerances of the oyster, Crassostrea virginica, salinity conditions in the estuary are good.

 

FWRI reports that water samples collected this week along the east coast of Florida detected Karenia brevis, the Florida red tide organism, between Volusia and St. Lucie counties.  Medium to high concentrations of K. brevis were detected alongshore between New Smyrna Beach (Volusia County) and Round Island Beach (southern Indian River County).  Very low to low concentrations were detected in St. Lucie County and background concentrations were detected in Martin County.

 

Caloosahatchee Estuary

 

No discharge occurred at S-79 last week.  The concentration of chlorides at the Olga Plant is 163 mg/l.  Average salinity increased at all monitoring sites over the past week. Shell Point was not reporting.  Weekly average salinities for specific sites are given below in parts per thousand (ppt).  Current weekly averages (in bold) may be compared to last week’s data (in parenthesis).

 

 

Weekly Average Salinity (ppt)

Sampling Site

Surface

Bottom

Franklin Locks (S-79)

15.9 (14.8)

16.6 (15.6)

Rt. 31 Bridge

15.7 (14.5)

17.4 (16.4)

I-75 Bridge

15.1 (14.1)

18.3 (16.9)

Ft. Myers Yacht Basin

21.3 (20.3)

21.8 (20.4)

Cape Coral Bridge

25.2 (25.6)

28.5 (27.7)

Shell Point

 

 

 

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

 

FWRI reports that water samples collected this week detected very low concentrations of Karenia brevis, the Florida red tide organism, at Marco Beach in Collier County.  All other samples collected between Pinellas and Collier County contained no K. brevis.


Water Conservation Areas

 

Good to Fair dry season recession rates continue to dominate the region except in WCA-1 where the rainfall caused water levels to increase by 0.06 ft.  Although recession rates were Good or Fair, the depths in the Everglades remain too deep for wading bird foraging.  This is normally not an issue at this time of year because foraging in support of nesting behavior does not usually begin until February.  Only the NW corner of WCA-3A has proper depths and recession rates to support wading birds.  However, it is unknown if birds are using this area and if fish for prey are available (fish may not have yet recovered from the current drought).  Stages in WCA-1 are right at Regulation, WCA-3 stages are below Regulation and WCA-2A remains about one foot above Regulation.

 

Everglades National Park

 

Mixed patterns for Everglades National Park (ENP) wetland water levels reflected the patchy distribution of precipitation over the week.  Taylor Sl. Bridge, an area that received nearly 1” of rain over the past 7 days, was the only station where water level was up for the week, by nearly 0.5”.  Water levels were down across other areas of ENP declining by 0.6” in the southern part of the system (both at Craighead Pond & in the panhandle at EVER6), and by 0.5” in Shark River Slough (@ P33).

 

Salinity remained generally stable across Florida Bay.  Taylor slough experienced a flow reversal.  Salinity concentrations at the Taylor River mouth were in the single digits early in the week, jumping up to 15 psu over the weekend before dropping back down < 10 psu yesterday.  In the Taylor River ponds the flow reversal that made it as far up as Pond 5 (where salinity jumped from < 1 psu to just over 5 psu) before salinity dropped back down yesterday; there was no such increase at Argyle Hendry (station TR) where salinity has remained below 1 psu. In the north-central Bay, salinity in Terrapin Bay and McCormick Creek remained low for much of the week (near 10 psu) before flow reversed quickly increasing salinity to just over 20 psu.  In central Florida Bay, Whipray Basin salinity held below 30 psu for another week.  In the SRS outflow at Tarpon Bay, salinity remained just over 4 psu through Sunday, 12/16.  As of now, the Bay appears to be well buffered in terms of salinity for the dry season.

 

Water Supply

 

Water levels in the upper and lower Kissimmee Basin and Lower West Coast continued to decline this week – and are below their historical average conditions for this time of year.  Water levels in the Lower East Coast are near their historical averages – although many wells recorded modest declines in the past week.  Water levels in the Upper East Coast continue to remain significantly above their historic averages.  Surface and groundwater levels in Water Conservation Areas 1 and 2 are near or slightly below their historic averages.  Water levels in WCA 3A continue to remain below their historic averages – and were somewhat lower this week.  Water levels in the southern-most portion of Dade County are near to their average historic conditions as a result of local rainfall.

 

The Water Supply Risk Measures were unchanged this week.  Six out of eleven water supply risk measures are in the “high” risk category - 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 Multi-Seasonal Net Inflow Forecasts remain at “medium” risk this week.

Chlorides at the Olga WTP on the Caloosahatchee River are now at 163 ppm – slightly above the concentration recorded last week - and the plant is currently operating.

 

WSE (Lake Okeechobee Regulation Schedule)

 

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

 

 

 

 

 

 

 

 

 

CC:   George Horne