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 7, 2009

 

SUBJECT:     Weekly Environmental Conditions for Systems Operations

 

Summary

 

Discharge from Lake Kissimmee is approximately 250 cfs and discharge at S65C is 200 cfs.  Lake Okeechobee stage is 12.04 feet NGVD, which is 0.14 foot lower than a week ago, 0.53 foot lower than a month ago, 1.69 feet higher than it was a year ago, and 0.89 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.

The declining water levels are again reflected this week in areas of the Water Conservation Areas (WCA) and Everglades National Park (ENP).  Wading bird feeding conditions are good in most of WCA-1, WCA-2B, middle WCA-3A, and southern WCA-3B, but water levels are below ground in WCA-2A, northern WCA-3A, and in ENP.  Groundwater levels continue the current downward trend across most of the District.

 

Background

 

Still cooler Wednesday night; some showers this weekend.  A cold front has pushed through the District and dry conditions have spread across the area with cooler temperatures expected through Thursday morning.  Southeasterly winds will moderate temperatures Thursday and Friday and allow some spotty showers to pop up mainly southeast each day.  The next cold front is expected to move into central Florida Saturday and stall Saturday night.  Scattered shower activity will pop up over the District Saturday and Sunday due to the frontal boundary.  The next ten days precipitation outlook is below average with moderate confidence.

 

Kissimmee Watershed

 

Over the last seven days, the upper Kissimmee Basin received 0.57 inches of rainfall and the lower Kissimmee Basin received 1.08 inches of (Daily Rainfall Report 4/03/09).

 

Stage in Lakes Kissimmee, Hatchineha and Cypress is 1.18 feet below regulation schedule.

 

Lakes Tohopekaliga and East Tohopekaliga are now at or very close to their regulation schedules.

 

Stage in Lake Tohopekaliga will be held at its current level until the gate at S61 can be repaired.  Once the gate is repaired, stage will be decreased gradually to meet the target of 52 feet on 5/15/09.  The Alligator chain of lakes is 0.65 foot below regulation and Lake Gentry is 0.68 foot below regulation schedule.

 

Lakes Hart and Mary Jane are 0.28 foot below regulation schedule.

 

Hydrilla treatments are scheduled for Lakes Kissimmee, Hatchineha and Jackson on 4/14/09 through 4/16/09.

 

According to the survey maps from 3/26/09, there are approximately 23 active nests on Lake Tohopekaliga, 2 on East Lake Tohopekaliga, 12 on Lake Kissimmee and 6 on Lake Istokpoga.

 

Discharge from Lake Kissimmee continues at about 250 cfs.  Discharge at S65C is about 200 cfs and the low stage target schedule has resumed (33 feet on May 15th unless there is a large rain event).

 

A turbidity plume in lower Pool C was observed over the weekend.  The plume is likely a result of establishment of flow through the newly constructed section of river channel and turbidity is expected to dissipate in a short amount of time.

 

Over the last seven days, dissolved oxygen  (DO) concentrations in the Kissimmee River ranged from 5.1 mg/L to 7.5 mg/L and averaged 6.1 mg/L.

 

Lake Okeechobee

 

According to the United States Army Corps of Engineers (USACE) web site, Lake Okeechobee stage is 12.04 feet NGVD, which is 0.14 foot lower than a week ago, 0.53 foot lower than a month ago, and 1.69 feet higher than it was a year ago.  The current stage is 2.14 feet below the historical average for this date and 0.89 foot below the simulated average using the current regulation schedule (LORS2008).  Total reported inflows are 268 cfs and are limited to flows through S65E.  No inflow data are reported for S133 and Fisheating Creek.  Total outflows are 2219 cfs and include releases to the Caloosahatchee River (47 cfs), water-supply releases through the S351, S352 and S354 (1985 cfs) and flow (187 cfs) through the S308.  Lake levels continue to decline with an average monthly lake level recession rate of 0.50 foot since the beginning of January.

 

The routine aerial wading bird survey of the lake’s littoral zone was conducted on Wednesday March 25, 2009 by Florida Atlantic University researchers as part of the RECOVER Monitoring and Assessment Plan.  The marsh has dried substantially and the Moore Haven and Indian Prairie littoral zone are dry except for the edges closest to the pelagic zone.  Most foraging birds are along these edges and near Cochran's Pass.  Nesting activity has increased since last month, although colonies that were observed in the Moore Haven area during the January and February surveys are no longer active because the area is dry.  Two new colonies were observed, one in Cochran's Pass and another colony with 200 nests about 2 kilometers from Clewiston Spit (further into the lake along the channel).

 

Great Egrets chicks are now hatching and the smaller herons are now laying eggs. White Ibis and Glossy Ibis are now building nests, mostly in cattails.  The colony in northern Indian Prairie has also increased in size with more nesting by Snowy Egrets and Tricolored Herons.  10 Roseate Spoonbills are nesting in the colony, with nest building activity confirmed on ground visits.  Eagle Bay also has nesting activity, although it is down from earlier surveys.

 

In total, eight colonies were detected.  Only four, however, were in the traditional littoral zone.  The others were at the gator farm, one at Lakeport, and two were on Clewiston Spit.  Although this year's nesting is considerably higher than the previous two years, it is not likely to be close to the outstanding year of 2006, probably because so much of the marsh is already dry.

 

Monday, April 6, 2009 District crews saw 30-40 egg masses of the native Florida apple snail in the canal between the Clewiston boat ramp and the Clewiston lock.  Eggs were also observed in the marsh south of the Clewiston channel.  The eggs were in an area dominated by spikerush but were mostly attached to sparse bulrush and cattail.

 

Saint Lucie Estuary

 

Over the past week discharge averaged 0 cfs at S-80.  Discharge from the Lake at S-308 averaged 86 cfs.  Provisional data indicates that a discharge of 0.04 cfs occurred at S-97 on C-23 and 20 cfs at 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)

 20.3 (20.4)

 21.3 (21.4)

 

HR1 (N. Fork)

 23.2 (24.1)

 23.9 (24.3)

 

Roosevelt Bridge

 25.8 (25.9)

 26.1 (26.2)

  8.0 – 25.0

A1A Bridge

 30.3 (31.1)

 31.7 (32.5)

20.0 – 31.0

 

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

 

Caloosahatchee Estuary

 

During the last week, discharge averaged 251 cfs at S-79, 300 cfs at S-78, and 578 cfs at S-77.  The concentration of chlorides at the Olga Plant was 145 ppm yesterday.  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 (10.3)

  6.2 (11.2)

Rt. 31 Bridge

    7.5 (12.0)

  9.0 (13.0)

I-75 Bridge

    9.4 (13.6)

13.0 (15.4)

Ft. Myers Yacht Basin

  18.6 (20.0)

19.0 (20.0)

Cape Coral Bridge

  26.3 (27.0)

27.0 (27.6)

Shell Point

  34.3 (34.0)

35.2 (35.8)

 

A seven-day pulse release at S-79 ended on Saturday, 4/4/09.  While average salinity declined throughout most of the estuary, the greatest decreases occurred in the narrow head waters of the estuary between I-75 and S-79.  Conditions in the upper estuary east of Fort Myers are poor (30 day average at Fort Myers equals 17.1 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 (FWRI) 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 DO concentration at Fort Myers (Shell Point  was unavailable) ranged from 5.3 to 9.9 mg/L


Water Conservation Areas

 

Recession rates have increased again, declining at rates considered good or fair throughout the WCAs.  WCA-2A and Northeast Shark River Slough are experiencing especially high recession rates, -0.31 and -0.33 foot, respectively, in one week:

 

Stage Change:            WCA-1:           -0.11 foot         WCA-3A:         - 0.10 foot

WCA-2A:         -0.31 foot        WCA-3B:         - 0.11 foot

WCA-2B:         -0.17 foot         NESRS:          - 0.33 foot

 

WCA-1 is still below its regulation schedule (about -0.2 foot).  WCA-2A canal stage (used from February to May) has fallen again to about -0.21 foot below schedule.  The WCA-3A marsh is below about -0.5 foot the bottom of Zone E1.

 

The declining water levels are again reflected in this week’s water depths map.  Large portions of WCA-1, WCA-2B, and WCA-3A are wet, but most of the rest of the Greater Everglades are dry.  Subsurface water depths continue to drop in the WCAs, Holeyland, Rotenberger, and in the Everglades National Park (ENP), which has large areas with water levels once again below -2.5 feet (as it was a month ago).  The drying front continues to head southward through northern WCA-3A, and nearly all of WCA-2A is dry.  The northern Refuge is now dry, and nearly the entire ENP except the coast is dry.  Water tables in Big Cypress Preserve have continued to dry; areas that are below -2.5 feet have expanded substantially from a month ago.

 

Wading bird feeding conditions are good in most of WCA-1, WCA-2B, middle WCA-3A, and southern WCA-3B, but water levels are below ground in WCA-2A, northern WCA-3A, and in ENP.  Recession rates are increasing with the higher evapotranspiration rates that are typical of this time of year.

 

The muck fire index indicates that most of the Greater Everglades are still in the low to moderate risk categories, except for parts of Holeyland, Rotenberger, WCA-2A, and a small portion of ENP

 

Everglades National Park

 

Only trace amounts of rain fell across ENP and Florida Bay last week.  Stations for which we receive data from ENP measured 0 – 0.3 inch of rainfall over the seven day period, and the basin-wide spatially-averaged weekly RAINDAR total was 0.01 for the ENP and C-111 basins.

 

Stages continued to decline last week.  Water level at the Taylor Slough Bridge declined by 4.6 inches (NOTE: data problems last week at station P33 preclude reporting the water level trend at this site).  To the south, water levels in the ENP panhandle (EVER6) and at Craighead Pond declined by 1.7 and 1.2 inches, respectively (NOTE: water level has once again dropped below the marsh surface in the ENP panhandle).

 

Salinity remained steady or increased in Florida Bay last week.  In the near shore eastern Florida Bay, salinity was steady in the mid-30s in Long Sound and increased slightly from the low 30s to mid-30s at the Little Madeira Bay platform.  Farther into Florida Bay at Duck Key, salinity was steady in the mid-30s.  The thirty day moving average salinity at the Taylor River platform (used for tracking the Florida Bay minimum flow levels) increased from 18.9 psu (3/29) to 24.4 psu (4/5), and the daily mean salinity rose from 29.3 psu to 33.6 psu (4/5).  In north central Florida Bay, salinity increased slightly to 40 psu in Terrapin Bay, and following an early week decline to the mid 30s, salinity increased to near 40 psu in McCormick Creek.  At the central Bay platform in Whipray Basin, salinity remained at 40 psu.  To the west, in the upstream reaches of Shark River Slough, salinity increased slightly from 20 to 22 psu

Water Supply

 

Groundwater levels continue the current downward trend across most of the District (with the exception of Orange, south Palm Beach and Lee counties).  Water levels in the Kissimmee Basin are declining, and wells in both the Surficial aquifer and the Floridan aquifer are at lower levels than they were at this time last year by two - three feet, although the Floridan aquifer wells in Orange County have seen some recovery over the last seven days.  Surficial aquifer in Orange County is now at the level of the 2001 drought.  Surficial aquifer levels in the Upper East Coast (UEC) region have resumed steady decline in Saint Lucie and Martin counties.  C-25 canal water level is approaching the shut-off criteria (for agricultural withdrawals) of 14.0 feet NGVD.  The C-25 is at 14.17 feet.  C-24 canal (S-49_H) level dropped below 16 feet (15.78 feet as of 3/31/09) and C-23 canal level went up 0.13 foot to 17.66 feet NGVD.  Surficial aquifer in northern Palm Beach County resumed decline during last week, and is a foot below the 2001 drought elevations.  Surficial aquifer levels in most areas of the Lower East Coast (LEC) region are gradually declining, and Homestead and South Dade aquifers turned to yellow indicator. Surface water levels in most of the C-111 basin have either red (S-176_H and S-18C_H) or yellow (S-177_H) indicators.  The Surficial aquifer levels in the Lower West Coast (LWC) region are declining, but still above last year’s levels.

Lower Tamiami aquifer wells are approaching or dipping below last year’s levels.  Mid-Hawthorn aquifer levels somewhat recovered in Lee County (three out of four wells).  Sandstone aquifer water levels have improved but are still approaching the Maximum Developable Limit in the Lehigh Acres area.

 

Water supply outlook: The only remaining water supply risk indicators in the “low” risk category are Water Conservation Areas 1 and 3A.  The projected LOK Stage for the next two months, the CPC Precipitation Outlook, the LOK Seasonal Net Inflow Forecast, the LOK Multi-Seasonal Net Inflow Forecast, and the Palmer Index for LOK Tributary Conditions continue in the “medium” risk category. Water Conservation Area 1 has moved back to “low” risk category due to levels at 1-8C being above Line 1 (15.38 feet).  As a result of recent rains, the water supply risk indicator for the entire LEC is now in the “yellow” risk category. Water Conservation Area 2A is in the “high” risk category, with headwater elevation at S11B below Line 2 (10.52 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 Thursday, March 12, District staff briefed the Governing Board on the hydrologic needs and the ecological status of the entire system.  At that time, the Board did not request the Corps make additional environmental water supply releases to the Caloosahatchee Estuary.  Since then, the eastern portion of the District has received additional rainfall.  This represents new information that was not available at the March 12 Board discussion.  All the new additional information has been made available to the USACE to assist in their decision-making.

 

 

 

 

 

 

 

CC:      George Horne

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