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:                        April 14, 2009

 

SUBJECT:     Weekly Environmental Conditions for Systems Operations

 

Summary

 

Discharge from Lake Kissimmee is approximately 250 cfs and discharge at S65C is 350 cfs.  Lake Okeechobee stage is 11.80 feet NGVD, which is 0.24 foot lower than a week ago, 0.63 foot lower than a month ago, 1.30 feet higher than it was a year ago, and 0.98 foot lower then the simulated average using the current regulations schedule.  Salinity conditions in the Saint Lucie estuary are considered to be fair based on the salinity preference of the oyster, Crassostrea virginica, and location in the estuary.  In the Caloosahatchee Estuary, salinity conditions are poor in the upper estuary, good in San Carlos Bay and good in the lower estuary.  Water levels are falling at rates considered fair or good throughout the WCAs), water depths are largely below ground in much of the Greater Everglades.  Wading bird feeding conditions are good in most of WCA-1 and middle WCA-3A and -3B.  Groundwater levels continue the current downward trend across most of the District.

 

Background

 

Strong storms extreme north on Tuesday.  A pre-frontal line of heavy showers and strong storms is moving into the Upper Kissimmee now.  This activity will move primarily eastward with some southward drift during the afternoon on Tuesday.  Winds are too strong for seabreeze formation, so will exclude showers/storms south of Lake Okeechobee (Lake) this afternoon.  By this Tuesday evening, some showers/storms may develop down to the Southwest Coast and Saint Lucie County before dissipating.  The associated cold front will slide down the peninsula overnight before reaching south Florida predawn.  Residual moisture, instability and convergence should pop a few showers/storms south of the Lake Wednesday afternoon.  Dry and pleasant conditions will follow on Thursday before a slow warming trend begins Friday.  Next chance for rain arrives around Monday.  The next ten days precipitation outlook is below average with moderate confidence.

 

Kissimmee Watershed

 

Over the last seven days, the upper Kissimmee Basin received 0.03 inches of rainfall and the lower Kissimmee Basin received 0.05 inches to bring the monthly totals to 1.10 (38% of average) and 1.71 (66% of average) inches respectively (Daily Rainfall Report 4/13/09).  

Stage in Lakes Kissimmee, Hatchineha and Cypress is approximately 1 foot below regulation schedule.  Lakes Tohopekaliga and East Tohopekaliga are now at or very close to their regulation schedules.  The Alligator chain of lakes is 0.57 foot below regulation and Lake Gentry is 0.61 foot below regulation schedule.  Lakes Hart and Mary Jane are 0.25 foot below regulation schedule.

 

Hydrilla treatments are scheduled for Lakes Kissimmee, Hatchineha and Jackson on April 14 through April 16, 2009.

 

Snail kites continue to nest on Lake Tohopekaliga, East Lake Tohopekaliga, Lake Kissimmee and Lake Istokpoga.

Discharge from Lake Kissimmee continues at about 250 cfs.  Discharge at S65C is about 350 cfs and the low stage target schedule has resumed (33 feet on May 15th unless there is a large rain event).

 

Over the last seven days, dissolved oxygen (DO) concentrations in the Kissimmee River ranged from 5.3 mg/L to 8.6 mg/L and averaged 6.9 mg/L.

 

Lake Okeechobee

 

According to the United States Army Corps of Engineers (USACE) web site, Lake Okeechobee stage is 11.80 feet NGVD, which is 0.24 foot lower than a week ago, 0.63 foot lower than a month ago, and 1.30 feet higher than it was a year ago.  The current stage is 2.22 feet below the historical average for this date and 0.98 foot below the simulated average using the current regulation schedule (LORS2008).  Total reported inflows are 130 cfs and are limited to flows through S65E.  No inflow data are reported for S133 and Fisheating Creek.  Total outflows are 3907 cfs and include environmental releases to the Caloosahatchee River (1805 cfs), water-supply releases through the S351, S352 and S354 (1784 cfs) and flow (323 cfs) through the S308.  Tuesday is the forth day of a nine day pulse release (averaging 650 cfs) to the Caloosahatchee River.  Lake levels continue to decline with an average monthly lake level recession rate of 0.62 foot since the beginning of January.

 

The “dry out” lake stages for 33 sites in the North, West and Fisheating Bay (FEB) that currently have sparse to dense beds of submerged aquatic vegetation (SAV) was predicted based on water depths recorded during the January to April SAV surveys (Dry out stages Apr 09 OPS.ppt).  These predicted “dry out” stages indicate that if lake stage reaches 10.0 feet. NGVD then half (17 of 33) of the sites that currently have SAV would go dry eliminating the SAV from those site.  In the North, 11 of the 18 SAV sites would go dry and three SAV sites in each of the West and FEB areas would go dry.  All of the sites along the western wall have dense beds of topped out and reproductive Vallisneria so fostering conditions that would allow the lake stage to remain above 10.5 feet would be beneficial to SAV maintenance and continued growth.  After the 2000 drought it took two to three years for sparse beds of SAV to emerge in areas that had been dry.

 

March water-quality monitoring results are now available.  Two of the 25 monitoring stations (FEBIN and FEBOUT) were not sampled due to low water conditions.  Total phosphorus averaged 124 ppb lakewide (compared to 138 ppb in February) and 104 ppb at nearshore stations (compared to 125 ppb in February).  Total suspended solids averaged 21 ppm lakewide (compared to 22 ppm in February) and 18 ppm at nearshore stations (compared to 20 ppm in February).

 

Saint Lucie Estuary

 

Over the past week, no flow was discharged at S-80. Discharge from the Lake at S-308 averaged 214 cfs.  Provisional data indicates that no discharge occurred at S-97 on C-23 and S-49 on C-24. The current weekly average salinities (in bold) at the four monitoring sites in the Saint 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)

20.7 (20.3)

21.1 (21.3)

 

HR1 (N. Fork)

23.8 (23.2)

24.6 (23.9)

 

Roosevelt Bridge

26.2 (25.8)

26.5 (26.1)

8.0 – 25.0

A1A Bridge

 30.4 (30.3)

 32.1 (31.7)

20.0 – 31.0

 

Salinity throughout the estuary remained about the same with last week.  At both the Roosevelt and A1A Bridges, weekly average salinity is slightly above the upper bound of the preferred range.  Salinity conditions in the estuary are considered to be fair considering the time of year, the location in the estuary, and salinity preference of the oyster, Crassostrea virginica.

 

Caloosahatchee Estuary

 

During the past week, discharge averaged 578 cfs at S-79, 493 cfs at S-78, and 903 cfs at S-77.  The concentration of chlorides at the Olga Plant was 120 ppm on Monday.  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

Franklin Locks (S-79)

 5.5 (5.5)

 6.4 (6.2)

Rt. 31 Bridge

 7.6 (7.5)

 9.0 (9.0)

I-75 Bridge

 9.7 (9.4)

11.4 (13.0)

Ft. Myers Yacht Basin

17.8 (18.6)

18.6 (19.0)

Cape Coral Bridge

25.9 (26.3)

26.9 (27.0)

Shell Point

34.2 (34.3)

35.2 (35.2)

 

A seven-day pulse release at S-79 began on Saturday, April 11, 2009.  Average salinity remained about the same for most part of the estuary except for a slight decrease between Fort Myers Yacht Basin and Cape Coral Bridge.  Conditions in the upper estuary east of Fort Myers are poor (30 day average at Fort Myers equals 18.1 ppt). Salinities at the Cape Coral Bridge are within the preferred range for the oyster, Crassostrea virginica, and well within the range tolerated by seagrass, Halodule wrightii.  Therefore, conditions in the lower estuary are good.  Salinity at Shell Point indicates that conditions are good in San Carlos Bay.

 

Fish and Wildlife Research Institute reports that water samples collected alongshore between Pinellas and Monroe counties contained no K. brevis.  (Monitoring data collected by the River, Estuary and Coastal Observing Network (RECON) of Sanibel-Captiva Conservation Foundation (SCCF) indicated chlorophyll at Fort Myers and Shell Point ranged from 1 to 7 mg/L (DO was unavailable).

 

Water Conservation Areas

 

Regional pan evaporation of 1.93 inches drove continuing large stage decreases throughout the Greater Everglades.  Water levels are falling at rates considered fair or good throughout the WCAs, but are particularly high in WCA-2A and Northeast Shark River Slough, -0.24 and -0.31 foot, respectively:

Stage Change:            WCA-1:           -0.16 foot         WCA-3A:         - 0.19 foot

WCA-2A:         -0.24 foot         WCA-3B:         - 0.19 foot

WCA-2B:         -0.19 foot         NESRS:          - 0.31 foot

All WCAs are far below their regulation schedules.  WCA-1 is about -0.5 foot below, WCA-2A canal stage (used from February to May) has fallen again to about -0.9 foot below, and the WCA-3A marsh is about -0.6 foot below the bottom of Zone E1.

 

Water depths are largely below ground in much of the Greater Everglades.  Except for coastal areas, Everglades National Park (ENP) is dry, with soil water depths well below -1 foot in most of the Park.  Similarly, Big Cypress Preserve water tables are -2 feet or more below ground level.  Surface water remains only in WCA-1, WCA-2B, WCA-3A, and WCA-3B.  Subsurface water depths continue to drop in the WCA-2A and -3A, Holeyland, and Rotenberger.  These water depths increase loss of peat through decomposition and provide higher possibilities of muck fires.

 

Most of the Greater Everglades have moved into the moderate muck fire risk category except for the wetter areas described above and along the coastal regions of ENP.  There is a high risk of muck fires in far northern WCA-3A, portions of WCA-2A, along Miami Canal in Rotenberger and Holeyland, as well as locally within ENP.

 

Wading bird feeding conditions remain surprisingly good in most of WCA-1 and middle WCA-3A and -3B.  The southwestern coastal areas of ENP are also showing good recession rates and depths for wading bird feeding, an improvement over last week.

 

Everglades National Park

 

No appreciable rain fell across ENP or Florida Bay last week.  Stations for which we receive data from ENP measured 0 – 0.06 inch of rainfall over the week, and the basin-wide spatially averaged weekly RAINDAR totals were 0.009” and 0.001” for the ENP and C-111 basins, respectively.

 

Stages continued to drop last week.  Water level in Shark River Slough has dropped by 4.6 inches since 3/29 (not reported 4/5), and water level at the Taylor Slough Bridge dropped by 5.2 inches last week.  To the south, water levels in the ENP panhandle and at Craighead Pond dropped by 2.0 and 1.9 inches, respectively.

 

Salinity remained steady or increased slightly in Florida Bay (Bay) last week.  Salinity remained in the mid-30s in the near shore eastern Bay at Long Sound and at the Little Madeira Bay platform, as well as farther into the Bay at Duck Key.  In the north central Bay, salinity in Terrapin Bay and McCormick Creek decreased mid-week into the mid 30s before increasing to 40 psu by week’s end.  At the central Bay platform in Whipray Basin, salinity increased from 40 psu to 43 psu.  In the upstream reaches of Shark River Slough, salinity remained steady at 22 psu. The rate of decline in ENP stages and increase in Bay salinity is higher than average, but is not surprising given the combined effects of low rainfall, high rates of evapotranspiration, and the recent strong southerly winds that drive Bay water northward.

 

The Taylor River platform 30 day moving average salinity increased last week from 24.4 psu (4/5) to 28.0 psu (4/12), and the daily mean salinity remained at 33.0 psu.  It is likely this year will produce a second year exceedance of the Taylor River minimum flows and levels (MFL), perhaps as early as next week.  A violation is set as a 30-day running average salinity of 30 psu or above at the Argyle-Hendry station in Taylor River.  The rule, set in early 2006, defines a violation as three consecutive years of exceedances once in ten years, or two sets of two consecutive years of exceedances in a ten year period.  This second consecutive exceedance is not yet a violation of the Florida Bay MFL rule, but involves the period between now and 2018.


Water Supply

 

Groundwater levels across the District continue to decline.  Floridan aquifer wells in the Kissimmee Basin remain between the lowest 30 and 10 percentile of their periods of records for this time of year, with last week’s increases having receded.  Surficial aquifer wells in the Kissimmee Basin are declining steadily, with water levels between the 10th and 1st percentile ranges.  Canal stages in the Upper East Coast (UEC) are still about two feet above the 14 foot agricultural pumping cutoff criteria due to recent rains.  Groundwater levels in the northern UEC are declining – northern Saint Lucie County well STL-125 is less than 0.3 feet above its all-time low.  In the southern coastal part of the UEC, groundwater levels are declining but remain higher than further north as a result of the boost from March rains.  Inland UEC well levels are steadily declining.  In the Lower East Coast (LEC), groundwater levels in southern Palm Beach and northern Broward counties remain high and are slowly declining.  Southern coastal Broward and Miami-Dade wells are beginning to drop into the “yellow” category again; however groundwater levels are still a few inches higher than in early March.  Conditions are drier in inland Miami-Dade County, particularly in the area between Tamiami Trail and Homestead/ Florida City, where levels have dropped to the lows seen just before the mid-March rains.  The Surfical aquifer levels in the Lower West Coast (LWC) are declining, with most wells reporting levels between the 30th and 10th lowest percentiles for this time of year.  Coastal Lower Tamiami aquifer water levels are holding steady, with most around the 30th percentile.  Inland, the Lower Tamiami levels are also steady, with most wells in their lowest 10th percentile.  Sandstone aquifer levels in the LWC are very low, particularly in Lee County near Lehigh Acres.  Mid-Hawthorn aquifer levels are close to median values in coast areas, generally between the 30th and 10th percentile range further inland, and are above the lows seen in 2007.

 

Water supply risk indicators in the “low” risk category include the Water Conservation Areas 1 and 3A.  The LOK Seasonal Net Inflow Forecast and the LOK Multi-Seasonal Net Inflow Forecast have also moved into the “low” risk category.  The CPC Precipitation Outlook, the Palmer Index for LOK Tributary Conditions, and the projected LOK Stage for the next two months continue in the “medium” risk category.  The water supply risk indicator for the entire LEC is in the “medium” risk category, with two days per week watering restrictions in place except for the utilities at risk.  Water Conservation Area 2A remains in the “high” risk category, with headwater elevation at S11B below Line 2 (10.12 feet).

 

LORS2008 (Lake Okeechobee Regulation Schedule)

 

Stages in Lake Okeechobee have now moved into the Beneficial Use sub-band.  Tributary inflows are currently in the dry category.  The seasonal outlook for net inflow into the lake is for dry conditions.  The multi-seasonal outlook is normal.

 

On Saturday, April 11, the Corps initiated a nine-day pulse release to the Caloosahatchee Estuary that will average 650 cfs per day.

 

 

CC:      George Horne