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:                 June 3, 2008

 

SUBJECT:         Weekly Environmental Recommendation for Systems Operations

 

Recommendation

 

No Lake Okeechobee regulatory releases to the south or estuaries are recommended.

 

Background

 

The cycle of daily afternoon showers and thunderstorms should continue this week.  An upper level trough will enhance shower coverage again today with a focus of activity over the interior and west.  As the upper trough shifts east of the District, sinking air on its back side will begin to suppress daily shower Wednesday through Friday and southeasterly winds will focus this activity west.  An upper level low is forecast to spin up in the base of the trough and drift westward during the week.  This low is expected to increase daily shower coverage Saturday and Sunday as it moves west of the District.  The next ten days precipitation outlook is near average with low confidence.

 

Kissimmee Watershed

 

Over the last seven days, the upper Kissimmee Basin received 0.08 inches of rainfall to bring the 30 day total to 1.37 inches (38% of average), and the lower basin received 0.09 inches to bring the 30 day total to 1.25 inches (33% of average) (Daily Rainfall Report 6/2/08).

 

Releases from East Lake Tohopekaliga (S-59) are approximately 177 cfs.  Releases from Lake Tohopekaliga (S-61) increased to approximately 800 cfs.  No other releases are being made at this time.  All upper Kissimmee Basin lakes are below regulation schedule.

 

In the upper basin, snail kites continue to nest on East Lake Toho, Lake Toho, and Lake Kissimmee.  Nests on Lake Toho continue to represent a large fraction of the total number of snail kite nests in Florida.

 

Flow has been reestablished to the Kissimmee River for 322 days (S-65 re-opened on 07/18/07).  Flow is approximately 200 cfs at S65 and 137 cfs at S-65C.

 

With the decreased inflow from the upper basin, water levels continue to decline across the Kissimmee River Restoration Project.  The water level at PC62, near the upstream end of the Phase I area, is currently 33.98 feet and the headwater stage at S-65C has is 33.31 feet, so that the water surface elevation decreases by 0.67 feet from the upstream end to the downstream end of the restoration project.  The floodplain in the restored reach is nearly dry except for isolated areas.  Numerous wood storks and other wading birds were observed foraging in isolated wetlands on the floodplain over the past week.

 

Dissolved oxygen concentrations in the river channel of the Kissimmee River ranged from 4.6 mg/L to 9.4 mg/L with an average of 7.3 mg/L.

 


Lake Okeechobee

 

According to the USACE web site, Lake Okeechobee stage is 9.55’ NGVD, which is 0.21’ lower than a week ago and 0.63’ lower than a month ago.  The current stage is 0.54’ higher than it was a year ago and 3.66’ below its historical average for this time of year.  Reported inflows include 319 cfs from the Kissimmee River.  Reported outflows include 32 cfs through the S77.  Outflows also are occurring through temporary forward pumps at S351, S352 and S354, at the rates of 660, 440, and 440 cfs respectively.

 

Submerged Aquatic Vegetation (SAV) west update – For the first time in several years we found Vallisneria and or Chara at all three Clewiston sites.  Although plant biomass is still low, Vallisneria and Chara are abundant along the entire west wall between Clewiston to FEB.  Secchi transparency was on the bottom > 1 mile off shore in about 0.9 m of water.

 

Five wildfires including:

·        Grassy Island – reported 5/01/08: 7:47pm. This wildfire is still 100% contained at 2,756.4 acres.  Producing some residual smoke.

·        Myakka Cut – reported 5/02/2008: 10:20am. This wildfire is 90% contained at 38,000 acres. Rekindled Memorial Day and smoking well into the interior.  This wildfire will require a significant amount of rain in order to control it.

·        Big Bear Beach – reported 5/17/08: 1:38pm. This wildfire is 90% contained at 227 acres.  This wildfire is near the town of Lakeport.  Disk lines (fire breaks) have been established along the rim from Moore Haven to the Kissimmee River.  Then the rim of the Lake serves as another fire break and finally there is a canal that separates the town from the wildfire that is in the lake.

 

St. Lucie Estuary

 

There were no releases through S-80 from C-44, S-48 from C-23, and  S-49 from C-24 over the past week.  The current weekly average salinities (in bold) at the four monitoring sites in the St. 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)

16.64 (18.89)

18.88 (20.14)

 

HR1 (N. Fork)

21.40 (21.67)

21.98 (22.90)

 

Roosevelt Bridge

NR (NR)

NR (NR)

8.0 – 25.0

A1A Bridge

29.56 (29.49)

30.67 (30.42)

20.0 – 31.0

 

Average salinity decreased slightly at HR1 and by 2 ppt at Palm City Bridge due to local runoff.  The average salinity increased slightly at A1A Bridge and is still unavailable at Roosevelt Bridge.  Based on salinity data collected at the other stations, it can be reasonably assumed that weekly average salinity at Roosevelt Bridge would be similar to what was two weeks ago (about 22-23 ppt).  The salinities at A1A Bridge are just within the upper limit of the preferred range.  Salinity conditions in the estuary are considered fair, based on the salinity preference of the oyster, Crassostrea virginica, at Roosevelt Bridge.  The current surface salinity at Roosevelt Bridge is unavailable but should still be below the maximum weekly average of 28.0 ppt achieved in May 2001 during the 2000 – 2001 drought.


Caloosahatchee Estuary

 

No discharge occurred through S-79 during the past week.  An average weekly discharge of 237 cfs occurred at S-77and 53 cfs at S-78.   The concentration of chlorides at the Olga Plant was 249 ppm yesterday, up from 248 ppm in the beginning of this reporting period.  Current weekly averages (in bold) may be compared to last week’s data (in parenthesis).

 

 

Weekly Average Salinity (ppt)

Sampling Site

Surface

Bottom

Franklin Locks (S-79)

19.49 ( 16.71)

20.85 (17.47)

Rt. 31 Bridge

19.47 (18.12)

21.58 (19.06)

I-75 Bridge

20.28 (19.44)

22.67 (20.51)

Ft. Myers Yacht Basin

26.48 (24.53)

27.23 (24.77)

Cape Coral Bridge

31.74 (31.89)

31.95 (32.51)

Shell Point

35.88 (35.86)

36.60 (36.51)

 

Average salinities increased 2 – 3 ppt in the upper estuary and remained about the same in the lower estuary.  Average salinity at the Ft. Myers surface sensor was 26.48 ppt, above the 1-day MFL criterion of 20 ppt.  The current surface salinity of 19.5 ppt at S-79 is 0.5 ppt below the maximum weekly average of 20.0 ppt achieved in May 2001 during the 2000 – 2001 drought.  Salinity at Shell Point and the Cape Coral Bridge is above the optimal range for the oyster, Crassostrea virginica.  Conditions in the upper estuary east of Ft. Myers are poor due to high salinity.  Conditions in the lower estuary downstream of Cape Coral are becoming poor considering the combine salinity preference of oysters and seagrasses.

 

Water Conservation Areas

 

Stages are holding steady throughout the Water Conservation Area’s (WCA’s).  Despite it being June and the “normal” start of the wet season, good recession rates have returned to the Everglades, except in WCA-3B, where a high rainfall cell caused water levels to rise.  Wading Bird foraging depths continue to be Fair in WCA-1, Good in WCA-2A and Fair in WCA-3A.  Stages are currently at regulation in WCA-1 and WCA-2A and slightly below regulation in WCA-3A .

 

Everglades National Park

 

The spatial pattern for rainfall was reflected in last week’s trends for Everglades National Park (ENP) wetland water levels.  Water levels in SRS (station P33) were up by 0.8” for the week.  The panhandle (station EVER6), on the other hand, saw water level drop by nearly 0.75”.  Taylor Slough Bridge (TSB) water levels dropped by 2.5” (not an unusual recession rate at this station) and by 1.2” to the south at Craighead Pond (CP), an area where water levels have been declining rapidly of late.  While this week’s recession rates are not particularly high, it is notable that May water levels were below the decadal average at both TSB & CP, by 17” & 10”, respectively.

 

Salinity continues to trend upward.  Salinity remained in the middle – upper 30s across most of the northeast Bay last week, while, in the Taylor ponds, salinity continued to climb for another week, reaching the mid-30s at Pond 5 (USGS station) and Argyle Hendry (ENP station TR).  As of Sunday, June 1st, the 30 day moving average concentration at TR (used for tracking the FL Bay MFL criterion of 30 psu) was at 32.1 psu (up from 30.4 psu last week).  Low rainfall, especially in the pan handle, and high evapotranspiration across the region continue to facilitate this MFL exceedance.  Salinity increased into the mid-40s in the northcentral Bay areas of McCormick Creek and Terrapin Bay.  The central Bay station in Whipray Basin, though, where salinity had been rapidly rising of late, held in the mid-upper 40s last week.  Salinity in the upstream reaches of Shark River (Tarpon Bay platform) measured above the seasonal norm (mid-teens), but fell a bit (just below 20 psu) due to higher rainfall totals in this part of the system.

 

Wildlife

 

Hydrologic conditions have finally become more conducive to foraging/nesting in a number of areas of the system.  The District does not usually conduct a June nest count so the current survey was relatively limited in scope and focused only on colonies that are active or had a good possibility of being so.  A total of 11175 nests (3400 egrets and 7775 White Ibis nests) were counted.  This is almost double last month’s count but considerably lower than during the peak of nesting in 2006 and 2007.  Most nesting activity was in the Refuge and WCA 3A.

 

Most foraging activity was observed in southern WCA 2A and northern WCA 3A. Little foraging was noted in the Refuge.

 

 

Water Supply

 

Although there was some scattered rain last week, most water levels decreased across most of the District.  Water levels in the upper and lower Kissimmee Basin are now slightly below their historical average conditions for this time of year.  Water levels in the Lower West Coast are now at or below historical averages, though most water levels (e.g., Sandstone Aquifer) are below those conditions depending on the degree of confinement of the aquifers.  Water levels in the Lower East Coast are near or slightly below their historical averages.  Water levels in the Upper East Coast are still slightly above their historic averages.  Surface and groundwater levels in Water Conservation Areas 1, 2 and 3 are now near their historic averages – although they have been declining over the past few weeks.  Water levels in the southernmost portion of Miami-Dade County are now significantly below their average historic conditions.

 

There was no change in the water supply risk indicators since last week.  Six out of the eleven water supply risk indicator parameters are now in the “low” risk category, including the CPC Precipitation Outlook, the Lake Okeechobee Seasonal and Multi-seasonal Net Inflow Forecast, and Water Conservation Areas 1, 2A and 3A.

 

Four out the eleven water supply risk indicators are now in the “medium” risk category, including the Palmer Index for Tributary Conditions (dry) and the LEC Service Areas 1, 2 and 3.

 

The only risk measure that is in the “high” risk category is the projected Lake Okeechobee Stage (water restriction zone).

 

 

LORS2008 (Lake Okeechobee Regulation Schedule)

 

The current Lake Okeechobee stage remains in the Water Shortage Management zone and is unlikely to move back into the Operational Band in the next several months during the persistent La Nińa climactic conditions.

 

CC:   George Horne