South Florida Ecosystem Restoration Working Group

Annual Report 1996


Part IV. 1996 SUBREGION ACCOMPLISHMENTS, INITIATIVES AND 1997 GOALS


SUBREGION V:
EVERGLADES WATER CONSERVATION AREAS

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


a. Ecosystem Problems and Restoration Objectives

Both water quality and quantity in the WCAs have been severely impacted as a result of their location between urban development and agricultural development and the water management operations of the C&SF Project. Since a major portion of the Kissimmee/Okeechobee and Atlantic Coastal Ridge drainage is diverted to the ocean for regulatory flood control, historic hydrologic flow through the WCAs has been severely reduced. The areas have been virtually isolated from the Kissimmee and Okeechobee watersheds and the sheetflow that was a critical element in the formation and ecological structure and function of the Everglades landscape has been eliminated.

There have been major hydroperiod impacts resulting from impoundment of these areas. Channelization coupled with impoundment has increased depth and hydroperiods at the southern end of the systems, while dewatering and shortening hydroperiods in the northern end. One result is extensive invasion by exotic plants, such as melaleuca, as well as numerous exotic fish. Another is the shortening of hydroperiods and reduction in water coverage vital to successful wading bird reproduction. This is particularly critical since these units provide major rookery and foraging habitat for wading birds in normal and dry years.

With drainage and development of the EAA, the WCAs serve as retention/detention systems for water storage and for input of agricultural drainage. Chronic introduction of drainage waters with elevated concentrations of nutrients, especially phosphorus, has resulted in massive conversions of sawgrass and wet prairie communities to stands of cattails and cattail/sawgrass mixes.

RESTORATION OBJECTIVES:

b. 1996 Accomplishments

Everglades ForeverAct/Everglades Program

Killed approximately 1.5 million melaleuca trees by manual herbicide treatment and hand-pulled over 1.7 million seedlings within the Everglades Protection Area. This brings the total melaleuca kill in the Everglades since 1991 to 6.3 million trees and 22.5 million seedlings. In addition, approximately 593 acres of dense melaleuca stands were killed through aerial herbicide treatment during 1996. To date, a total of 843 acres of dense melaleuca monoculture have been aerially treated in the Everglades Protection Area.

Constructed a temporary boardwalk and experimental network of enclosed chambers in the Loxahatchee National Wildlife Refuge for phosphorus dosing studies to determine the threshold (i.e., no imbalance) phosphorus concentration. Experiments using a similar setup in WCA 2A were continued throughout 1996.

Produced vegetation maps of WCA 2A that showed significant increase in cattail coverage between 1991 and 1995.

Completed preliminary analyses of water quality and biological data collection along a nutrient gradient in WCA-2A. These data, coupled with data generated in controlled dosing experiments in WCA-2A, will aid in establishing the "no imbalance" threshold phosphorus concentration.

Drafted permit to operate non-ECP structures.

Reviewed background data and drafted report evaluating water quality criteria applicable to Everglades Protection Area pursuant to EFA.

Drafted report evaluating water quality criteria applicable to EAA pursuant to EFA.

Levee 28 Modification Study

Initiated development of a plan to restore more natural hydrologic conditions in the Big Cypress National Preserve and enhance the overall restoration goals for south Florida.

The acquisition of Frog Pond enabled early construction of Pump Station S-332D. Currently S-332 is the only pump station that can be used to discharge water to Taylor Slough.

Assessed existing conditions with hydrologic modeling and defined areas to be restored in the study area.

Established high accuracy elevation data for the terrain in WCA-3B and the agricultural area adjacent to Levee 31.

c. 1996 Initiatives

Ecologic Programs

Initiated a program to develop an initial target to rescale the Natural System Model in WCA-2 and WCA-3 in order to optimize depths and hydroperiods for fish and wildlife.

Established high accuracy elevation data for the terrain in WCA-3B and the agricultural area adjacent to Levee 31.

Initiated a program to define a hydrologic regime that would optimize habitat for wildlife in the WCAs.

d. 1997 Goals

Levee 28 Modification Study

Complete the L-28 Study feasibility phase with the evaluation and recommendation of a plan with the following goals:

  1. Re-establish natural flow characteristics and restore hydrologic conditions in support of improving existing wetland habitat and benefiting historic fish and wildlife resources.
  2. Maintain flood control.
  3. Improve continuity between habitats.
  4. Effectively monitor hydrologic and ecological effects of project modifications.
  5. Provide water quality consistent with ecological needs.
The acquisition of Frog Pond enabled early construction of Pump Station S-332D. Currently S-332 is the only pump station that can be used to discharge water to Taylor Slough. Pump Station
Aerial view of Frog Pond
Phosphorous tolerances are studied in enclosed chambers along a temporary boardwalk in the Loxahatchee National Wildlife Refuge. Chamber
Aerial view of boardwalk

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