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:                 July 3, 2007

 

SUBJECT:         Weekly Environmental Recommendation for Systems Operations

 

 

Recommendation

 

No regulatory releases to the south or estuaries are recommended.

 

Background

 

An active thunderstorm day.  An upper level low located off the west coast of Florida will bring favorable upper level wind flow to the area today.  Some surface convergence also remains across the District along a trough which extends from a weak low located off the coast of the Carolinas.  Expect daytime heating to generate thunderstorms focused along bands across south Florida and across the Kissimmee Valley.  As the upper level low moves south and southwestward the next couple of days, conditions for thunderstorms will become less favorable over the southern portion of the District.  Therefore expect daily thunderstorm activity to be focused north and east Tuesday and Wednesday.  Thunderstorm coverage will then decrease a bit Thursday and Friday and be focused over the interior and east.  The next ten days precipitation outlook is near average with low confidence.

 

Kissimmee Watershed

 

The upper Kissimmee Basin received 1.32 inches of rainfall over the last 7 days to bring the 30-day total to 5.69 inches (77% of average) and the lower basin received 1.20 inches to bring the 30-day total to 4.08 inches (58% of average) (Daily Rainfall Report for 7/02/07).

 

The majority of snail kites are associated with Lake Tohopekaliga and Lake Kissimmee.  The most recent surveys include a number of fledglings.  Many active nests, including some recent nests, are still present on Lake Tohopekaliga.

 

No water releases are being made at this time.  The Kissimmee River has lacked flow for 237 days (gates at S-61 and S-65 were closed Wednesday 11/8/2006).  Concentration of dissolved oxygen in the Phase I restored river channel has been above thresholds of concern with mean daily values exceeding 3.50 mg/L.

 

Lake Okeechobee

 

According to the USACE web site, Lake Okeechobee stage is 8.82’ NGVD today which is 0.10’ lower than it was a week ago and 0.19’ lower than it was a month ago. Surface inflows are 93 cfs. and surface outflows are not reported due to missing S77 and S308 data.

 

One third of the monthly SAV sampling is complete and moderate to dense beds of Chara were observed off of the north west tip of Ritta Island and east of Kreamer Island in Pelican Bay


St. Lucie Estuary

 

No releases occurred at S-80 over the past week.   At the Roosevelt Bridge salinity averaged 21.7 ppt on the surface and 22.0 ppt on the bottom for the week.  Corresponding values further downstream at the A1A Bridge are 28.4 ppt and 29.3 ppt.  Salinities at both sites are within the preferred range (8-25 ppt for the Roosevelt Bridge and 20-31 ppt for the A1A Bridge).

 

Caloosahatchee Estuary

 

Discharge occurred at S-79 on one day over the past week (weekly average 40 cfs).  Chloride concentration at the Olga Plant is presently 166 mg/l.  Weekly average surface salinity ranged from 16.2 ppt at S-79 to 21.6 ppt at Ft. Myers. Bottom salinities ranged from 18.4 ppt at S-79 to 22.9 ppt at Ft. Myers.  Salinity at Shell Point averaged 36.4 ppt on the surface and 37.6 ppt on the bottom.  Salinity remains high in the upper estuary.  In the lower estuary and San Carlos Bay high salinities are good for seagrass and fair for oysters.

 

There have been reports of anoxic bottom water around the Route 31 Bridge.  A combination of warm temperatures, the deep navigation channel in this area and stratification of the water column is the likely cause.

 

FWRI reports that no Karenia brevis, the Florida red tide organism, was detected alongshore this week in samples collected between Pinellas and Collier counties.  Discolored water due to a bloom of the non-toxic cyanobacteria Trichodesmium is possible in southern Lee County.

 

Water Conservation Areas

The stage increased for most of the Everglades, but not significantly.  In WCA-1 depth is about 0.8 ft, but stage increased by only 0.05 ft for the week. In WCA-2A, the depth is still relatively low at 0.17 ft, but inundation was good at 0.13 ft. WCA-2B is something of an enigma where the gage near the canal dropped by 0.11 ft and the interior site (EDEN-13) increased by 0.26 ft. Enhanced seepage due to urban withdrawals may be the cause.  In the northern sections of WCA-3A water levels actually dropped by as much as 0.18 ft and the northeastern section of the region is -0.33 below ground. WCA-3B had fair re-wetting rates and has an average depth of 0.89 ft, which is good. The NESRS had a good re-wetting rate this week but is still relatively shallow for this time of year (depth=0.63 ft).  WCA-1 and 3 are below Regulation and WCA-2A is right at Regulation.

 

Everglades National Park

 

Rainfall was patchy across ENP & FL Bay again last week, with the panhandle region of ENP & the Bay proper receiving more rainfall than areas to the north & west.  The range of precip recorded across the basin (at the stations for which we receive data) was 1.2” – 5.2” as a 7 d accumulation.  This is not well reflected in the RAINDAR weekly ENP basin-wide spatial average accumulation of 2.0”.

Water levels across the area displayed mixed patterns for another week.  In SRS at P33 and at the Taylor Slough Bridge, water levels were down again by ~ 0.75”.  In the southern part of the system, down at Craighead Pond (station CP), water levels did not change from last week.  In contrast, in the panhandle (at EVER6), water levels were up considerably by 2.6”.

Salinity continued to drop or remain low across FL Bay last week.  Salinity at Trout Ck. remained in single digits for much of the week.  The platform at the mouth of L. Madeira Bay read salinity concentrations in the mid-20s, dropping slightly from last week’s upper 20s.  Salinity in the Taylor River ponds remained < 5 psu all week (~ 3 psu @ Pond 5 & nearly fresh up at Argyle Hendry).  The 30 d moving average concentration at TR continues to decline, remaining well below the 30 psu point (at 5.0 psu as of Sunday, 7/1).  Salinity is expected to remain low in the ponds for the remainder of the wet season.  Salinity concentrations held steady in the north central Bay areas of McCormick Ck. and Terrapin Bay, into the lower-20s or below 20 psu.  In the central Bay, Whipray Basin salinity held near 35 psu for yet another week.  On a trip taken on Friday (6/29) the measured salinity was 20 psu in Garfield Bight.  This is well below average for this time of the wet season (normally salinity is near 30 psu this time of year @ GB), further highlighting the fact this part of the system has received copious rainfall & flow is making its way into FL Bay.  To the north and west, Tarpon Bay (SRS outflow) salinity dropped to near 2 psu as of Sunday, 7/1. 

Until the great disparity between the southern and northern rainfall patterns in the Everglades subsides, we are not likely to experience an optimistic frame of mind.

 

Water Supply

 

Water levels in the Lower West Coast continue to remain near low levels for their periods of record, although rebound continues to occur in the coastal areas of Upper and Lower East Coast and Water Conservation Area 1 as a result of local rainfall.

 

Five out of eleven water supply risk measures are in the “high” risk category this week.  The projected Lake O Stage (SSM), the Palmer Index for Tributary Conditions and Lower East Coast Service Areas 1, 2 and 3 are all in the high risk category.  Water Conservation Areas 1 and 2A are now in the low risk category.  The Lake Okeechobee Multi-seasonal Net Inflow Forecast and Water Conservation Area 3A stage are now at medium risk.  The CPC Precipitation Outlook remained at “low” risk this week, along with the LOK Seasonal Net Inflow forecasts.

 

The chloride concentration at the Olga WTP is at 166 mg/L today.  There was no significant news to report on “Utilities of Concern” monitored by the Water Supply Department this week.

 

WSE (Lake Okeechobee Regulation Schedule)

 

The current Lake O stage – at 8.82’ 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