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 28, 2009

 

SUBJECT:     Weekly Environmental Conditions for Systems Operations

 

Summary

 

Discharge from Lake Kissimmee is approximately 600 cfs and will be incrementally increased to approximately 1000 cfs.  Lake Okeechobee stage is 11.29 feet NGVD, which is 0.28 foot lower than a week ago, 0.83 foot lower than a month ago, 1.10 feet higher than it was a year ago, and 1.19 foot lower then the simulated average using the current regulation 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 level recession rates are considered good for wading bird feeding in most of Water Conservation Area (WCA) WCA-1, WCA-3A and -3B.  Groundwater and surface water levels continue the current downward trend across most of the District.

 

Background

 

Mostly dry for the next week.  High pressure over the area will limit shower development the next few days.  Breezy southeast winds will bring some light showers south and south east.  There is the potential for some scattered afternoon shower activity this weekend.  The next ten days precipitation outlook is below average with moderate confidence.

 

Kissimmee Watershed

 

Over the last seven days, the upper Kissimmee Basin received 0.02 inches of rainfall and the lower Kissimmee Basin received 0.05 inches (Daily Rainfall Report 4/27/09).  Stage in Lakes Kissimmee, Hatchineha and Cypress is approximately 0.5 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 0.42 foot below regulation and Lake Gentry is 0.44 foot below regulation schedule.  Lakes Hart and Mary Jane are very close to regulation schedule.

 

Discharge from East Lake Tohopekaliga and Lake Tohopekaliga is 256 cfs and 630 cfs respectively.

 

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

 

Discharge from Lake Kissimmee continues at about 600 cfs and the floodplain of the Kissimmee River is essentially dry.  Some shoaling has been reported in the river channel in northern Pool B/C.

 

A slight turbidity plume (presumably from the ongoing construction) is visible in lower Pool B/C and northern Pool D.  Discharge at S65C is about 200 cfs.  Over the last seven days, dissolved oxygen (DO) concentrations in the Kissimmee River ranged from 5.5 mg/L to 7.8 mg/L and averaged 7.0 mg/L.

Lake Okeechobee

 

According to the USACE web site, Lake Okeechobee stage is 11.29 feet NGVD, which is 0.28 feet lower than a week ago, 0.83 feet lower than a month ago, and 1.10 feet higher than it was a year ago.  The current stage is 2.40 feet below the historical average for this date and 1.19 feet below the simulated average using the current regulation schedule (LORS2008).  Total reported inflows are 165 cfs and are limited to flows through S65E.  No inflow data are reported for S129, S133 and Fisheating Creek.  Total reported outflows are 2867 cfs and include releases to the Caloosahatchee River (274 cfs), water-supply releases through the S351, S352 and S354 (2288 cfs) and flow (579 cfs) through the S308.  No outflow data were reported for the S77, but a pulse-flow release to the Caloosahatchee began on Tuesday.

 

An apple snail mark-recapture experiment is being conducted on the lake to assist in the development of methods for large-scale snail stock enhancements.  Last Wednesday, Okeechobee Division staff tagged 1500 adult apple snails obtained from the District-funded snail-rearing facility at Harbor Branch Oceanographic Institute.  The following day, the snails were released in Eagle Bay marsh (outside the dike) across a 55m x 55m area.  All but 10 snails survived tagging and transport to the lake.  Sampling will be conducted at the release site every few days for the next month using standardized recapture methods to estimate survival and dispersal of juvenile and adult apple snails and reproduction.  Information gained from this study will provide valuable information on the acclimation, survival, and reproductive output of laboratory reared snails released into the wild that will be used to optimize protocols for future releases.

 

Saint Lucie Estuary

 

Over the past week, no discharge occurred at S-80.  Discharge from the Lake at S-308 averaged 345 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 (20.5)

 21.9 (21.5)

 

HR1 (N. Fork)

 25.3 (24.8)

 26.3 (25.7)

 

Roosevelt Bridge

 27.6 (27.3)

 27.6 (27.5)

  8.0 – 25.0

A1A Bridge

 31.3 (31.6)

 33.2 (33.4)

20.0 – 31.0

 

Salinity throughout the estuary increased slightly last week, except at A1A Bridge which had a slight decrease.  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, no discharge occurred at S-79.  Discharge averaged 128 cfs at S-78, while discharge at S-77 was unavailable.  The concentration of chlorides at the Olga Plant was 157 ppm on Sunday.  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)

    NR (5.3)

  9.1 (6.4)

Rt. 31 Bridge

    8.5 (5.3)

  9.1 (7.0)

I-75 Bridge

    9.6 (6.0)

11.4 (9.6)

Ft. Myers Yacht Basin

  17.1 (14.8)

17.9 (18.5)

Cape Coral Bridge

  24.7 (24.7)

25.6 (25.2)

Shell Point

  34.7 (34.1)

34.8 (34.5)

 

Average salinity increased throughout the estuary.  Conditions in the upper estuary east of Fort Myers are poor (30 day average at Fort Myers equals 17.2 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 dissolved oxygen concentration at Fort Myers and Shell Point ranged from 5.2 to 7.5 mg/L and chlorophyll at Fort Myers and Shell Point ranged from 1.0 to 16.0 mg/L.

 

Water Conservation Areas

 

The high rate of pan evaporation (1.80 inches), continues to draw down water levels, which are declining at rates considered fair or good for wading birds throughout the WCAs, but were particularly high in WCA-2A and -3A, -0.30 and -0.28 foot, respectively, last week.  WCA-2A is dry.

 

Stage Change:            WCA-1:           -0.17 foot         WCA-3A:         - 0.28 foot

WCA-2A:         -0.30 foot         WCA-3B:         - 0.15 foot

                                    WCA-2B:         -0.18 foot         NESRS:          - 0.03 foot

 

All WCAs remain far below their regulation schedules.  The WCA-1 marsh is about -0.5 foot below, WCA-2A canal stage has dropped to about -1.4 feet below, and the WCA-3A marsh is about -0.5 foot below Zone E1.

 

Twenty gauges in Big Cypress, the WCAs, and in Everglades National Park (ENP) have bottomed out (so recorded water levels are incorrect).  Gauges that are recording correctly have been used to produce this week’s maps, but until water levels rise, map areas representing Big Cypress are probably incorrect.

 

Water depths are below ground in much of the Greater Everglades.  Except for coastal areas, ENP is dry, with soil water depths well below -1 foot in most of the Park.  Water depths -1 foot or below exist in WCA-2A and the northern half of WCA-3A.  Surface water remains only in parts of WCA-1, WCA-2B, southern WCA-3A, and WCA-3B.

 

The driest areas of the WCAs are now in the high risk category for muck fires, and most of the Greater Everglades at moderate risk.  The wetter sections of WCA-1, WCA-2A, and WCA-3A and -3B, and coastal ENP are still in the low muck fire risk category.

Wading bird feeding conditions remain good in parts of WCA-1, -3A, and -3B.  The rest of the Greater Everglades are too dry, with a few areas still too deep for feeding.  With continuing high evaporation rates, these areas will continue to provide for future foraging for a while.

 

Everglades National Park

 

Light rain fell across ENP and Florida Bay last week, with moderate to heavy rain across coastal Dade County to the east.  ENP measured 0 – 0.5 inches, and the basin-wide spatially-averaged weekly RAINDAR totals were 0.03 and 0.19 inches for the ENP and C-111 basins, respectively.

 

Stages continued to drop last week.  Water levels in Shark River Slough and at the Taylor Slough Bridge dropped by 2.5 and 3.6 inches, respectively.  To the south, water levels in the ENP panhandle and at Craighead Pond dropped by 2.2 and 2.9 inches, respectively.  NOTE: Water level is now below the wetland surface at all of these four monitoring stations.

 

Salinity was mostly steady or increasing in Florida Bay last week.  Salinity increased slightly to near 39 psu in Long Sound, at the Little Madeira Bay platform, and farther into the Bay at Duck Key.  The 30 day moving average salinity at the Taylor River platform used for tracking the Florida Bay minimum flow and levels increased from 30.2 psu (4/20) to 33.5 psu (4/26), with a daily mean salinity of 37.1 psu as of April 26.  In the north central Bay, salinity increased from 40 to 47 psu mid-week before dropping back to the low to mid-40s by the end of the week in Terrapin Bay and McCormick Creek.  At the central Bay platform in Whipray Basin, salinity remained in the middle 40s.  To the west, in the upstream reaches of Shark River Slough, salinity was steady at 18 psu.

 

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 record for this time of year, while continuing a steady decline.  Some Floridan wells in western Orange County and northeastern Polk County are at their lowest 10th to 1st percentiles now.  Surficial aquifer wells in the Kissimmee Basin are declining steadily, with water levels between the 10th and 1st percentile ranges.  Headwater stage at the S-68 structure on Lake Istokpoga has dropped to 37.91 feet, approaching the floor elevation of 37.5 feet. Canal stages in the Upper East Coast (UEC) are approaching the 14 feet agricultural pumping cutoff criteria.  The C-24 canal is closest to the cutoff level, with headwater stage at S-49 at 14.92 feet on Monday 4/27.  Groundwater levels in the northern UEC are declining – northern St. Lucie County well STL-125 is approaching its all-time low.  In general, water levels are a bit higher near the coast and towards the south of the UEC as compared to inland and north.  Monitor well PB-565 in Tequesta is at 1.82 feet, which is nearly at the minimum level desired to maintain a one foot mound against saline intrusion (1.80 feet).  In the Lower East Coast, groundwater levels in southern Palm Beach and northern Broward counties remain high and are slowly declining.  Broward and northern Miami-Dade wells have higher water levels with respect to their periods of record than do wells located further inland and further south.  Conditions are very dry in Miami-Dade County, particularly south of Tamiami Trail (US 41).  The Surfical and Lower Tamiami aquifer levels in the Lower West Coast (LWC) are declining, with most wells reporting levels in their lowest 30th to 10th percentiles.  Sandstone aquifer levels in the LWC are very low, particularly in Lee County near Lehigh Acres; however, there were some increases in water levels, presumably due to public outreach efforts.  Mid-Hawthorn aquifer levels in the LWC are close to median values near the coast and are generally between the 30th and 10th percentile range further inland.

 

Water supply risk indicators in the "low" risk category include the LOK Seasonal Net Inflow Forecast and the LOK Multi-Seasonal Net Inflow Forecast.  The Palmer Index for LOK Tributary Conditions is in the “high” risk category this week. The CPC Precipitation Outlook, the projected LOK Stage for the next two months, and WCA 1 continue in the "medium" risk category.  Water Conservation Area 3A has moved into the "medium' risk category this week as well.

The water supply risk indicator for Service Areas 1 and 2 in the LEC is in the "medium" risk category, with two days per week watering restrictions in place except for the utilities at risk.  Service Area 3 in the LEC has moved into the “high” risk category because of dry conditions in south Miami-Dade. Water Conservation Area 2A remains in the "high" risk category, with headwater elevation at S11B below Line 2 (9.64 feet).

 

LORS2008 (Lake Okeechobee Regulation Schedule)

 

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

 

 

 

 

 

CC:      George Horne