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 14, 2007

 

SUBJECT:         Weekly Environmental Recommendation for Systems Operations

 

Recommendation

 

No regulatory releases to the south or estuaries are recommended.

 

Background

 

Moderate thunderstorm activity focused over the southern half of the District today, then drier through the weekend.  A trough moving into the northern portion of the District will move into the Florida Straits Wednesday.  This trough will tap moisture in place over the southern half of the District to generate showers and thunderstorms.  Dry air behind the trough will suppress most shower activity through the weekend.  Next week's weather is heavily dependent upon the long-term track of Tropical Storm Dean.  The next ten days precipitation outlook is below average with low confidence.

 

Kissimmee Watershed

 

The upper Kissimmee Basin received 0.21 inches of rainfall over the last 7 days to bring the 30-day total to 8.10 inches (120% of average) and the lower basin received 0.54 inches to bring the total for the month to 7.52 inches (122% of average) (Daily Rainfall Report for 08/10/07).

 

Stages in the upper basin lakes are slightly below regulation schedule (Lake Tohopekaliga, East Lake Tohopekalga, and Hart and Mary Jane).  Lake Kissimmee has risen to within 0.44 ft below the regulation schedule for this time of year (summer pool).

 

Releases are being made from Lake Tohopekaliga (758 cfs), East Lake Tohopekalga (175 cfs), and Hart and Mary Jane (94 cfs).

 

Flow has been reestablished to the Kissimmee River for 27 days (S-65 re-opened on 07/18/07).  Discharge at S-65 continues at approximately 500 cfs.

 

Dissolved oxygen in the river channel has increased in the last week and is now above thresholds of concern (> 2 mg/L).

 

Lake Okeechobee

 

According to the USACE web site, Lake Okeechobee stage is 9.46’ NGVD today which is the same as it was a week ago and 0.36’ higher than it was a month ago.  Surface inflows are 1210 cfs. and surface outflows are not reported due to missing S77 and S308 data.

The annual mapping of the entire submerged aquatic vegetation (SAV) community is concluded.  The abundance of SAV at approximately 277 shoreline sites has been documented and preliminary results indicate that Chara is the dominant plant species covering approximately 28,664 acres along the southern and western shorelines.

Coverage in the northern region was limited to approximately 494 acres of very sparse Vallisneria near the southwest corner of King’s Bar.  Light algal bloom formations were observed at many of the southern and western sites during this survey.

Approximately 8,000 acres of torpedograss from the Indian Prairie marsh south to the Moore Haven marsh are currently being treated at a rate of approximately 670 acres per day.  The intent is to treat at least 12,000 acres this year while lake levels are low.

 

St. Lucie Estuary

 

No releases occurred at S-80 over the past week.  Salinities on the surface remained about the same this week at 4.7 ppt in the South Fork (Palm City Bridge) and 3.5 ppt in the North Fork (Harbor Ridge Station).  Bottom salinities were down slightly in these same locations to 5.2 ppt and 6.7 ppt, respectively.  At the Roosevelt Bridge, averaged salinities were 9.5 ppt on the surface and about 10 on the bottom, remaining within the preferred range of 8-25 ppt. Corresponding values further downstream at the A1A Bridge were up slightly from last week to about 17 ppt and 22 ppt, which is near the bottom of the preferred range (20-31 ppt). Therefore, salinity conditions are fair in the estuary.

 

Caloosahatchee Estuary

 

The average discharge at S-79 was up this week to 363 cfs and the monthly average discharge is 252 cfs. Chloride concentration at the Olga Plant remain stable, averaging about 83 mg/l.  Average surface salinity in the upper estuary during the last week also was nearly unchanged, with both S-79 and the I-75 Bridge sensors reporting 4.6 ppt.  Bottom salinities ranged from 4.8 ppt to 7.9 ppt, respectively.  The salinity sensors at Ft. Myers are providing sporadic information.  Surface salinities appear to be near 10 ppt for the week and the 30 day average remains above 10 ppt . Average surface and bottom salinity for the week at the Cape Coral Bridge was 18 and 20.1 ppt.  The average bottom salinity at Shell Point was 31.9 ppt. Salinity conditions in the upper estuary are fair and they are good in the lower estuary.

 

FWRI reports that no Karenia brevis, the Florida red tide organism, was detected this week in water samples collected alongshore between Pinellas and Collier counties. Discolored water due to a bloom of the cyanobacteria Trichodesmium has been reported offshore along the southwest Florida coast and remains possible alongshore in portions of Charlotte, Lee (including San Carlos Bay) and Collier counties.

 

Water Conservation Areas

Rainfall amounts resulted in modest net increases in water depth for all regions with the exception of WCA-1 (-0.08’).  Marsh depths now range between 0.68 ft (6-3 gage) and 1.7 ft. (6-5 gage) (Note: Gage 99 is not considered a marsh gauge.), and continued increases are seen as good thing for the environment.  In terms of the Regulations Schedules; WCA-1 is below regulation, WCA-2A is above Regulation, and WCA-3A is below.

 

Everglades National Park

 

Trends in water levels across the Everglades National Park (ENP) wetlands have been mixed over recent weeks.  Some areas, like in the southern Taylor Slough area of Craighead Pond (CP), have remained unusually stable for several weeks now.  In other extremities of the Park, such as in Shark River Slough (P33) & in the panhandle (EVER6), there has been a slow decline over recent weeks, the timing of which corresponds with local rainfall accumulation (or lack thereof).  Water level at Taylor Slough Bridge has displayed a more variable pattern of late (fluctuation that is typical of this station).

A weekly decline of > 6” is fairly significant even at Taylor Slough Bridge showing just how sensitive the Rocky Glades is to local rainfall patterns (this station received < 0.1” of rain last week, a week with very high temps & ET).

 

Salinity continued to remain seasonably low & stable across FL Bay.  Trout Ck. salinity was somewhat flashy last week, generally holding in single digits with brief periods rising over 10 psu.  Salinity at the mouth of Taylor River was more variable, ranging between 2 – 15 psu throughout the week (seasonable concentrations).  Salinity concentrations in the Taylor River ponds remained very low for the 7 day period, close to 1 psu.  At the mouth of L. Madeira Bay salinity held near 20 psu for much of last week.  In the north-central Bay, McCormick Ck. salinity increased a bit from last week, remaining in the mid-20s for much of the week.  South of here, in Whipray Basin, salinity also started to climb a bit, likely a result of low local rainfall & high evaporation, but remaining near seasonable levels.  Salinity to the west in the Shark River Slough outflow of Tarpon Bay stayed low at near 2 psu for another week.

 

Water Supply

 

Water levels in the Lower West Coast (LWC) continue to remain near low levels for their periods of record, and water levels generally decreased 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 decreased on average 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 remains at medium risk this week.  The CPC Precipitation Outlook remains 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