South Florida Ecosystem Restoration Working Group

Annual Report 1996



[1996 Accomplishments] [1996 Initiatives] [1997 Goals]

a. Ecosystem Problems and Restoration Objectives

Changes in the natural hydrologic cycle in the Everglades National Park include water levels, surface-water inundation, and water flow. Completion of the Tamiami Trail in 1928, the first east-west road across the basin, altered and interrupted water patterns and blocked all natural sheetflow. Present flow patterns in ENP are limited and controlled by management of the WCAs to the north, extensive agricultural and urban pumping, and drainage canals to urban areas to the north and east. Unnatural hydroperiods and hydropatterns throughout ENP are now typical, resulting in sharp reductions of seasonal water levels and large discharges for flood control purposes. These have been both ecologically significant and deleterious. Ground water from the Biscayne Aquifer flows into Biscayne Bay modifying salinity and possibly carrying pollutants into the bay waters.

ENP is presently subject to intense disruptions of historic geochemical processes due to human activities along its margins and, to some extent, from atmospheric transport. With the advent of intense land-use change, notably artificial drainage and cultivation within the EAA and development of the Atlantic Coastal Ridge, phosphorus and other substances are delivered to the Everglades in quantities significantly above historic levels. One consequence of such enrichment is extensive development of cattail stands in phosphorus-enriched areas formerly dominated by sawgrass.

Changes in water quality, quantity, and distribution have had ramifications throughout the Park. The total number of wading birds nesting in the Big Cypress and Everglades basins has declined by more than 95 percent from peak estimates of nesting birds in the 1930s.

Understanding the relationships between decline in wading birds and changes in hydropatterns that have resulted from water management practices will require increased study of the (1 ) dynamics of prey populations and (2) specific foraging strategies and patterns associated with successful nesting of wading birds. Some of the changes in aquatic communities that form the food base for wading birds are subtle and difficult to detect in the early stages until they are manifested in obvious collapses of native communities and natural processes. A good example is the recent finding of mercury at dangerous levels in fishes and their predators. Also, non-native fishes have colonized natural and disturbed habitats during the past three decades. The rate at which fishes have been introduced has increased since the mid-1 970s. Several introduced species of herpetofauna also occur in ENP, and colonizations will likely continue.

Water management strategies have caused reduced reproductive effort, in creased frequencies of nest flooding, and increased rates of juvenile mortality for the American alligator, one of the most ecologically significant of the larger vertebrates in the Everglades.

The continuing and possibly accelerating loss of species diversity of both flora and fauna from upland communities is of great concern. Invasion of the natural vegetation communities by exotic pest plants, especially melaleuca and Brazilian pepper, is one of the most serious problems in ENP. It is possible these and other invasive species may modify the water table and hasten extinction of native species.


b. 1996 Accomplishments

Modified Water Deliveries to ENP

Placed 25% of the western 8.5 Square Mile Area on the Save Our Everglades land acquisition list. All required public coordination was completed. This acquisition will be incorporated into the Modified Water Deliveries to ENP Project.

Solicited residents of the 8.5 Square Mile Area to determine their interest in selling properties. Over 100 affirmative responses were received from residents and landowners in the western area. The appraisal process will be initiated in early 1997 to pave the way for land acquisitions.

Completed design memorandum for relocation of the Tigertail Camp to avoid flooding associated with restoration of Shark River Slough and prepared construction contract plans and specifications for the site preparation.

Obtained Water Quality Certification for Modified Water Deliveries to ENP.

Experimental Program of Water Deliveries to ENP

Developed an ecological and hydrologic monitoring network to evaluate impacts of operational modifications for the seventh iteration of tests in Shark River Slough and Taylor Slough.

Ecologic Programs

Developed a success criterion for restoration based on periphyton in the Everglades.

Treated over 302,000 Melaleuca trees at 1182 new sites and 339 old sites within Everglades National Park. Mechanical and chemical treatment was accomplished by a seven member crew during the dry season (January through May). Over 60 square miles were retreated and the treat ment area was expanded by 10 square miles. An estimated 10 to 40 million trees were treated by aerial spraying.

Documented the timing of vegetational changes over the last two millennia in sites located in the mangrove fringe near Taylor Slough. Collected a transect of cores along Taylor Slough for analysis of biotic and geochemical changes over the last few millennia.

Released female, radio-tagged Texas cougars in south Florida in order to reverse the effects of inbreeding and genetic loss to the remaining endangered Florida panther population. Radio tracking showed that the Texas cougars' ranges overlapped ranges of known male Florida panthers. Two females released in Everglades National Park have one kitten each. Additionally, a Texas cougar released in Big Cypress has two kittens and another cat located in Fakahatchee Strand State Preserve has one kitten.

C-111 Project

Acquired approximately 300 acres in the Rocky Glades in 1996. Of the 10,500 acres of land needed for completion of the C-111 South Dade Project, 6,439 are now under public ownership. Acquisition of the 5,200-acre Frog Pond, previously used for agriculture, was completed in 1995.

Issued water quality certification for C-111 Mounds Degrading Project involving removal of 750,000 cubic yards of dredged material along the southern side of the C-111 canal. This will improve sheetflow of freshwater to ENP and Florida Bay.

Initiated construction of the C-111 Project through the award of a construction contract for S-332D. This pump station will help to partially reflood portions of the Taylor Slough headwaters.

Completed the Feature Design Memorandum, prepared plans and specifications and awarded construction contract for removal of spoil mounds along southern C-111. This will facilitate more natural flows across the ENP panhandle and into Florida Bay.

Modified the project cooperation agreement to establish a 50/50 cost share for Corps and SFWMD as authorized by WRDA 1996.

Hole-in-the-Donut Project

Awarded contracts for the engineering, construction, and environmental reclamation for the Hole-in-the-Donut Wetland Restoration and Mitigation Program.

Initiated construction and environmental reclamation to eradicate Schinus terebinthifolius (Brazilian pepper).

Constructed three four-channel flumes in Everglades National Park, one in Loxahatchee National Wildlife Refuge, in pristine "wet prairie' marshes to investigate the effects of low-level phosphorus additions on Everglades wetlands. Information from this research will be used to determine the threshold phosphorus concentration. Female panther kitten born in September in Everglades National Park (photographed at one month of age).

c. 1996 Initiatives

Experimental Program of Water Deliveries to ENP

Initiated a water quantity, water quality and biological monitoring program designed to determine the effects of a four year iteration of the Experimental Program of Water Deliveries to ENP.

Modified Water Deliveries to ENP

Awarded construction contract for S-355A and B, two new structures that will discharge water from WCA-3B into northeast Shark River Slough. This is the first construction for the Modified Water Deliveries to ENP Project.

Initiated land acquisition for more than $4 million for the levee/canal right-of way in the 8.5 Square Mile Area.

C-111 Project

Assisted in the development of measures to ensure adequate water quality in the Everglades through establishment of an interagency water quality team.

Established the Southern Everglades Restoration Alliance (SERA) composed of all agencies that have a role in the restoration of the southern Everglades. SERA will coordinate the activities of these agencies to ensure consistent and complementary programs.

Began participation in the Diversified Organization for Ecosystem Restoration and Sustainability (DOERS) composed of agricultural, environmental, and agency representatives to coordinate mutually beneficial solutions to water resources problems in south Dade County.

Ecologic Programs

Initiated a project to investigate the ground water and sediments of the Biscayne Aquifer. Coring and analyses will begin during 1997.

d. 1997 Goals

Experimental Program of Water Deliveries to ENP

Plug existing, non-project canals south of S-175 to facilitate more natural flows in Taylor Slough.

Add an additional pump unit at S-331 to minimize excessive canal drawdowns while still providing adequate protection against flooding.

Prepare an annual report documenting hydrologic and ecologic conditions that have occurred since November 1995 when Iteration 7 was initiated.

Modified Water Deliveries to ENP

Finalize a design for mitigation, flood protection, and water quality system for the 8.5 Square Mile Area.

Continue land acquisition for the right-of way for the canal and levee system in the 8.5 Square Mile Area.

Evaluate design modifications for flows through WCA-3B.

Determine the need for modifications to Tamiami Trail for restoration of flows to northeast Shark River Slough.

Initiate planning and design of facilities to address water quality in the western C-11 basin. Pump station S-9 currently pumps untreated water from this basin into WCA-3A. These discharges are conveyed by the L-67A canal directly to the S-12 structures which discharge into ENP.

Best Management Practices

Initiate a cost-shared demonstration project to improve water use efficiency and reduce leaching of fertilizers into groundwater. Using new soil moisture sensor technology, tropical fruit and vegetable growers in the C-111 basin will be able to refine irrigation schedules and test fertilization rates developed specifically for South Dade soils and crops.

Involving the Public

Conduct a groundbreaking ceremony that publicly recognizes the beginning of Everglades restoration.

C-111 Project

Complete Feature Design Memorandum for the Taylor Slough Bridge Improvements, complete plans and specifications, and award the construction contract.

Complete construction of S-332D and initiate operations to begin hydrologic restoration of Taylor Slough.

Initiate a pilot test for a periphyton stormwater treatment area in the Frog Pond to evaluate this technology for use in the C-111 project.

Hole-in-the-Donut Project

Complete removal of Brazilian pepper on 200 acres and begin removal from an additional 250 acres.

Begin environmental monitoring of vegetation, hydrology, and wildlife in the 200 42 acre parcel.

Begin a supplemental Environmental Assessment to assess possible on-site disposal alternatives for Hole-in-the-Donut substrate. Consideration of alternatives will include disposal methods and location, revegetation preferences, and impacts of alternative disposal on South Dade County agriculture.

Implement the Hole-in-the-Donut Science Program, a research program to identify alternative restoration methods and to develop an approach for long-term tracking.

East Cape and Homestead Canal Plugs

Complete construction of plugs in pre-project canals to prevent overdrainage of the southern Everglades.

Ecologic Programs

Begin the subsurface investigation of the Biscayne Aquifer with coring at ten sites and the installation of monitor wells. Sediments recovered will be analyzed for lithologies and permeabilities.

Complete coring of eastern Everglades and Buttonwood Embankment for analysis of extent and timing of vegetational change over the last few millennia.

Hole-in-the-Donut in the Everglades provides a monitoring area which with help scientists determine environmentally sound solutions.

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