LAKE TOHOPEKALIGA, LAKE OKEECHOBEE, ST. LUCIE AND CALOOSAHATCHEE ESTUARIES

DRAWDOWN ISSUES FACT SHEET

November 2003

[ Background | Present Conditions | Future Needs | Recommendations ]

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Flood control activities in central and south Florida have resulted in habitat degradation in the upper Kissimmee Chain of Lakes (including Lake Tohopekaliga), Lake Okeechobee and St. Lucie and Caloosahatchee estuaries. Such activities have resulted in many issues that must be addressed to preserve the health of these important resources.

Because of these emerging issues a Florida Fish and Wildlife Conservation Commission (FWC) Lake Tohopekaliga Issue Team was formed to address issues surrounding Lake Tohopekaliga and the Upper Kissimmee Chain of Lakes and associated resources to the south. Additionally, the development of a long-term management plan (LTMP) for the upper Kissimmee basin has been initiated.

This plan will address water management issues to provide flood control and water supply while limiting environmental stresses within the Kissimmee Chain of Lakes and resources to the south. Furthermore, the U.S. Army Corps of Engineers (USACE), South Florida Water Management District (SFWMD) and FWC have initiated an evaluation of the current water fluctuation schedule for Lake Okeechobee.

A 2003-04 extreme drawdown and habitat enhancement project has been proposed for Lake Tohopekaliga to improve habitat conditions in the near-shore, vegetated portions of the lake. Currently, the habitat in this zone is characterized by poor plant community structure and excessive organic accumulation. The proposed project will result in substrate improvements and a diverse aquatic plant community, providing improved fish and wildlife habitat.

Once completed, implementation of the LTMP should prolong the positive effects of the extreme drawdown and habitat enhancement project. Since the FWC Issue Team, based on SFWMD hydrologists’ input, believes the volume of water to be discharged during the extreme drawdown of Lake Tohopekaliga is negligible and will not cause further damage of resources to the south, the FWC Lake Tohopekaliga Issue Team offers the following:

BACKGROUND INFORMATION:

Lake Tohopekaliga

· This lake has been negatively impacted by flood control practices since 1970.

· There has been little enhancement work performed since 1987 to curtail negative impacts of flood control operations on Lake Tohopekaliga.

· Since the early 1980s exotic aquatic plants, namely hydrilla, have expanded throughout the lake and now cover approximately 14,000 acres of the lake. Expansion has occurred throughout the open water and near-shore, vegetated portions of the lake.

· Urban development within the watershed continues to escalate leading to additional point and non-point sources of pollution, namely increases in nutrients such as phosphorus and nitrogen.

· Without intervention, aquatic habitat in Lake Tohopekaliga will continue to be diminished over time.

Lake Okeechobee

· Extended high water since August 2002 (above 15 feet National Geodetic Vertical Datum [NGVD]) has resulted in detrimental impacts to bulrush (a native emergent aquatic plant) due to both high water levels and increased exposure to wave energy. The bulrush community will not experience appreciable recovery and further expansion until lake levels approach 12.0 ft NGVD.

· While aquatic vegetation losses have occurred, the acreage remaining is still greater than the amount existing prior to the managed water level recession in 2000 and subsequent drought of 2001. Spikerush, bulrush, eelgrass, pondweed and hydrilla can be found lake-wide in historical areas of location.

St. Lucie and Caloosahatchee Estuaries

· Water quality has been poor, characterized by high turbidity, low dissolved oxygen and low salinity due to high freshwater discharge volumes from Lake Okeechobee for flood control throughout 2003.

· Sentinel oysters died, indicating natural populations are stressed or, in some cases, may be dead due to freshwater discharges.

· Sea grasses are stressed due to the high volume of freshwater discharges.

· Only a few reports of fish lesions have been reported. For the St. Lucie estuary, nine reports involving 27 fish have been received since July 1, 2003. For the Caloosahatchee estuary, five reports involving six fish since July 1, 2003.

· Monthly sampling in the St. Lucie estuary by staff from the Florida Marine Research Institute (FMRI) resulted in no fish with lesions being collected.

· The Fish Health group of the FMRI participated with local guides to locate lesioned fish on November 4, 2003, with no impacted fish collected; however, they observed a group of mullet with lesions.

PRESENT CONDITIONS:

Lake Tohopekaliga

· Near-shore and open water habitat in Lake Tohopekaliga continues to deteriorate. Approximately 14,000 acres are dominated by invasive and exotic species of aquatic plants, which have contributed to the accumulation of approximately 6.7 million cubic yards of organic sediment.

· The local economy continues to be negatively impacted as anglers, tournaments, etc., relocate to other resources due to the scheduled extreme drawdown. This has been exacerbated by postponements of the project over the past three years.

· As of November 5, 2003, water levels are 0.5 feet below high pool on Lake Tohopekaliga and 2.4 feet below high pool on lakes Cypress, Hatchineha and Kissimmee.

· As of November 5, 2003, the volume of water to be moved to accomplish the enhancement project was 95,840 acre-feet in Lake Tohopekaliga and 72,000 acre-feet for lakes Cypress, Hatchineha and Kissimmee, a total volume of 168,000 acre-feet. (An acre-foot equals the volume of water contained in one acre with a water depth of one foot; nearly 326,000 gallons)

· This total volume equals approximately 0.37 feet (4.4 inches) of depth on Lake Okeechobee, assuming no evapotranspiration or water withdrawals for agricultural activities. Of this amount, all but approximately one inch will be discharged to Lake Okeechobee prior to June 1, 2003, even if the drawdown is cancelled.

· This volume corresponds to approximately 710 cubic feet per second (cfs) of water flow over a four-month period (from November 1, 2003 until March 1, 2004).

Lake Okeechobee

· As of November 5, 2003, Lake Okeechobee stage is 16.3 feet NGVD, nearly a foot lower than on October 1, 2003 (approximately 17.1 feet NGVD).

· The amount and timing of water coming into Lake Okeechobee from the Lake Tohopekaliga extreme drawdown is expected to have minimal, if any, additional detrimental impacts to the ecology of Lake Okeechobee, assuming normal seasonal weather patterns. It is important to note that the long-term weather forecast for central and southern Florida is a normal precipitation pattern (i.e., no El Nino effect, unlike winter/spring 2002-2003). The water will be coming during a period when, typically, water demands on the lake by the Everglades Agricultural Areas increases, rainfall is at its lowest, and evaporation is high due to lower humidity. In a normal weather pattern, evaporation rates during the January-May period can be expected to exceed surface inflow to the lake.

· The duration and timing of water entering the lake due to the drawdown will probably result in no noticeable change in lake elevation. Wind activity on the lake results in lake-wide water level oscillations of 0.5 feet on a daily basis.

St. Lucie and Caloosahatchee Estuaries

· The estuaries continue to be stressed by freshwater discharge.

· As of November 5, 2003, Level II pulsed discharges are being conducted from Lake Okeechobee to the estuaries. It is anticipated that discharges will be reduced to Level I pulses the week of November 10, 2003, rainfall permitting.

· Monthly sampling by FMRI staff for leisioned fish is ongoing for the St. Lucie estuary.

· Neither estuary is in as poor of a condition as reported during 1998-1999 El Nino years, but anglers, guides, hotel owners, etc. are currently reporting negative economic impacts.

FUTURE NEEDS:

Lake Tohopekaliga

· Following the enhancement project, implement the LTMP when available and immediately initiate various management activities such as herbicide treatments to prolong beneficial impacts of the extreme drawdown and habitat enhancement project.

Lake Okeechobee

· Implement enhancement projects deemed necessary to facilitate recovery of habitat. For example, a restoration project is scheduled to begin January 2004 on Ritta and Kreamer islands in the southern lake area. On Ritta Island approximately four miles of agricultural levees will be degraded and an abandoned dragline removed. On Kreamer Island, approximately 1.92 miles of agricultural levees will be degraded and two abandoned water control structures will be removed. The goals of this restoration project are re-establishing hydrologic connections inside these natural islands and the surrounding lake, protecting native habitat for the proliferation of the endangered Okeechobee gourd, and increasing the spatial extent of willow and pond apple to gain benefits for wading bird populations. The project is a partnership with the SFWMD with funding from the Lake Okeechobee Protection Plan.

· Support implementation of a more desirable water fluctuation schedule for Lake Okeechobee and continue to evaluate the schedule. The FWC Lake Okeechobee and Associated Estuaries Issue Team recommended the following water level and discharge management strategy:

Water levels in Lake Okeechobee should be kept between 12.0 and 15.5 feet NGVD, with these low and high water levels being met every three years. Annually, water levels within Lake Okeechobee should be dropping from November through June, stable through August and peaking in October.

St. Lucie and Caloosahatchee Estuaries

· Resist continuous discharges and back-to-back Level III pulse releases from Lake Okeechobee, rainfall permitting.

· Encourage Level I or Level II pulse releases coupled with recovery periods of no freshwater discharge between releases, rainfall permitting. This will enhance recovery of the estuaries.

· Investigate possible enhancement projects, in partnership with other appropriate groups and agencies, necessary to facilitate recovery of habitat and marine species.

· The FWC Lake Okeechobee and Associated Estuaries Issue Team recommended the following water level and discharge management strategy:

Timing of discharges to the Caloosahatchee and St. Lucie Rivers and Water Conservation Areas should be timed to match natural hydrologic cycles as much as possible (i.e., major discharges should occur during annual wet periods). Discharge events to the St. Lucie estuary greater than 2,000 cfs and flows greater than 4,500 cfs to the Caloosahatchee estuary should be avoided to minimize adverse effects on estuarine ecology; however, in regard to the Caloosahatchee estuary, minimum fresh water flows of 800 cfs in the spring and 1,200 cfs in the fall are needed to maintain optimum salinities for submerged aquatic vegetation.

RECOMMENDATIONS:

· Continue with the Lake Tohopekaliga extreme drawdown as proposed.

· Transition water from Lake Tohopekaliga into lakes Cypress, Hatchineha and Kissimmee until mid to late December to delay discharges to Lake Okeechobee and buffer associated estuaries from further discharge.

· Once the Lake Tohopekaliga extreme drawdown and habitat enhancement project is completed, continue lowering Lake Okeechobee to at least 13.5 feet in elevation while limiting discharges to estuaries to maintain optimal salinities.

· Evaluate the need and cost-effectiveness for enhancement projects for Lake Okeechobee, St. Lucie and Caloosahatchee estuaries.

· Continue to re-evaluate the Water Supply/Environmental water level schedule for Lake Okeechobee and development of the LTMP.

· Participate in the development of the Conservation Everglades Restoration Plan projects particularly the water storage reservoirs and the integration of public use and fish and wildlife management plans.

· Work with SFWMD to implement the Headwater Revitalization Project to re-establish historical high water elevations on lakes Cypress, Hatchineha and Kissimmee.

FOR THE CURRENT QUARTERLY FISHING FORECAST FOR LAKE TOHO AND OTHER LAKES SEE FISHING SITES AND FORECASTS.

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