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:                 August 7, 2007

 

SUBJECT:         Weekly Environmental Recommendation for Systems Operations

 

Recommendation

 

No regulatory releases to the south or estuaries are recommended.

 

Background

 

Afternoon storms mainly west.  Deep easterly winds have returned to the peninsula.  Easterlies guide the east coast seabreeze steadily westward where it can collide with the west coast seabreeze.  This scenario should dominate through Thursday afternoon.  The relatively undisturbed upper level pattern should translate into below average rainfall with a focus west each afternoon.  Changes begin Thursday night and Friday when a tropical wave moves through the peninsula.  Rains may increase, but these features are often over-hyped with respect to rain production.  The next ten days precipitation outlook is near average with low confidence.

 

Kissimmee Watershed

 

The upper Kissimmee Basin received 2.31 inches of rainfall over the last 7 days to bring the 30-day total to 8.51 inches (127% of average) and the lower basin received 2.33 inches to bring the total for the month to 8.40 inches (136% of average) (Daily Rainfall Report for 08/06/07).

 

Stages in the upper basin lakes continue to rise with several of the lakes reaching regulation schedule (Lake Tohopekaliga, East Lake Tohopekalga, and Hart and Mary Jane).  Lake Kissimmee has risen to within 0.48 ft below the regulation schedule for this time of year (summer pool).

 

Releases are being made from Lake Tohopekaliga (1000 cfs), East Lake Tohopekalga (175 cfs), and Hart and Mary Jane (80 cfs).

 

Snail kites continue to nest on Lake Tohopekaliga. No update from three weeks ago.

 

Flow has been reestablished to the Kissimmee River for 20 days (S-65 re-opened on 07/18/07).  Discharge at S-65 continues at approximately 500 cfs.  Discharge through the restored reach of the river is approximately 1000 cfs with the additional 500 cfs coming from tributary inflows and basin runoff.

 

After dropping to very low levels last week, the concentration of dissolved oxygen in the river channel has increased in the last week but remains below thresholds of concern.  At one location, values have risen but are still below 1 mg/L, where a fish kill may occur.  At the other, concentrations have risen above 1 mg/L but are still below 2 mg/L, where fish may begin to become stressed.  Water levels should allow fish access to the floodplain.

 

On Friday August 3, 2007, an algal bloom was reported covering most of Persimmon Mound Run (a remnant river channel in Pool A of the Kissimmee River).  Algal blooms were not observed in the C-38, which had flowing water, or in Rattlesnake Hammock Rum, another remnant river channel in Pool A.

Lake Okeechobee

 

According to the USACE web site, Lake Okeechobee stage is 9.46’ NGVD today which is 0.27’ higher than it was a week ago and 0.43’ higher than it was a month ago. Surface inflows are 3276 cfs. and surface outflows are not reported due to missing S77 and S308 data.

This week we began our annual Submerged Aquatic Vegetation (SAV) mapping effort.  The entire submerged plant community of the lake is mapped with an intensive program that includes over 700 sites around the shoreline.  The abundance of SAV at each site (center of each grid cell) is documented and the total number of acres of each dominant plant species is determined and coverage maps are developed.

An increase in algal bloom formations is anticipated as nutrient rich runoff increases with increased rainfall.

St. Lucie Estuary

 

No releases occurred at S-80 over the past week, and an average of 919 cfs flowed into Lake Okeechobee through S-308 from the C-44 canal during 6 of the 7 days.  Even though there was no discharge from S-80, salinities on the surface were down to 4.5 ppt in the South Fork (Palm City Bridge) and 3.4 ppt in the North Fork (Harbor Ridge Station).  Bottom salinities were 5.6 ppt and 9.3 ppt, respectively.  At the Roosevelt Bridge, averaged salinities were down 5 ppt from last week to 8.1 ppt on the surface and 8.5 ppt on the bottom due to local basin runoff (preferred range 8-25 ppt).  Corresponding values further downstream at the A1A Bridge were also down 5-6 ppt to 15.2 ppt and 19 ppt and were below the preferred range of 20-31 ppt.  Therefore, at the Roosevelt Bridge and upstream the salinity conditions are fair and are fair-poor at the A1A Bridge.

 

Caloosahatchee Estuary

 

The estimated weekly average discharge at S-79 was down about 290 cfs from last week to 83 cfs, with no flow occurring during the previous 4 days.  The monthly average discharge from S-79 was 237 cfs, which is below the MFL target of 300 cfs and the preferred minimum level of 450 cfs.  Average flow for 24 of the previous 30 days from C-43 to Lake Okeechobee was about 796 cfs.

 

Chloride concentration at the Olga Plant did not change appreciably during the last week and is presently 86 mg/l.  Average surface salinity was down about 2 ppt in the upper estuary, ranging from 4 ppt at S-79 to 4.8 ppt at the I-75 Bridge sensor.  Bottom salinities ranged from 4.2 ppt at S-79 to 7.2, respectively.  The salinity sensor at Ft. Myers collapsed and no surface or bottom readings are available.  However, the 30 day average salinity remains above the 10 ppt MFL target.  Surface salinity at Shell Point also was not available, but bottom salinity continued to decline slightly again this week, averaging 31.6 ppt.  Salinity remains too high in the upper estuary.  In the lower estuary and San Carlos Bay salinity conditions are good.

 

Access to the FWRI weekly summary of the Florida red tide organism was unavailable at the time of this estuarine conditions report.


Water Conservation Areas

Rainfall exceeded evaporation for most regions and this resulted in net increases in water depth for all regions with the exception of WCA-3B (-0.06’).  Marsh depths now range between 0.62 ft (6-3 gage) and 1.56 ft. (6-5 gage) (Note: Gage 99 is not considered a marsh gauge.), and continued increases are seen a good thing for the environment.  In terms of the Regulations Schedules; WCA-1 is at Regulation, WCA-2A is above Regulation, and WCA-3A is below regulation.

 

Everglades National Park

 

No data was received from Everglades National Park (ENP) since last Tuesday.  We are using USGS & SFWMD data to provide an update for conditions in this area and will try to resolve data issues from ENP by next week.  Overall ENP experienced a net loss of water depth of -0.12’.  Salinity continues to remain seasonably low & stable across FL Bay.  Trout Ck. represented the 1 exception, having experienced a mid-week flow reversal that pushed FL Bay water northward and increased salinity concentration in the creek upwards of 20 psu before dropping to a seasonal level (~ 5 psu) over the weekend.  Salinity at the mouth of Taylor River was generally remained below 10 psu for another week.  Salinity concentrations in the Taylor River ponds held very low all week (close to 1 psu in Pond 5).  In the north-central Bay area of McCormick Ck. salinity rose briefly mid-week into the mid-20s before dropping back towards 20 psu by the weekend.

 

Water Supply

 

Water levels in the Lower West Coast (LWC) continue to remain near low levels for their periods of record, although water levels generally increased in the LWC over the past week.  Water levels declined slightly in the coastal areas of the Upper East Coast and Lower East Coast over the past week, but they remain above their historical averages.  Surface and groundwater levels increased over the past week in the Kissimmee Basin.

 

Four out of eleven water supply risk measures are in the “high” risk category this week including the projected Lake O Stage (SSM), 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 Palmer Index for Tributary Conditions remains at medium risk.  The LOK Multi-Seasonal Net Inflow Forecast decreased from high to medium risk this week.  The CPC Precipitation Outlook remained at “low” risk this week, along with the LOK Seasonal Net Inflow forecast.

 

WSE (Lake Okeechobee Regulation Schedule)

 

The current Lake O stage – at 9.46’ today - remains in the Water Shortage Management zone and is unlikely to move back into Zone E in the next two months.

 

 

 

 

 

 

CC:   George Horne