South Florida Ecosystem Restoration Working Group

Annual Report 1996


Part IV. 1996 SUBREGION ACCOMPLISHMENTS, INITIATIVES AND 1997 GOALS


SUBREGION IV:
EVERGLADES AGRICULTURAL AREA

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


a. Ecosystem Problems and Restoration Objectives

Soil subsidence, caused primarily by microbial oxidation of organic matter under aerobic conditions, is a major ecological issue in the EAA. Drainage has caused significant subsidence of as much as 5 feet over a 50-year period, with an average rate of 1.2 inches per year. Due to improvements in water-table management, the annual subsidence rate in the EAA now is probably less than the historic average.

The most practical method to reduce subsidence is to maintain water tables as close to the soil surface as possible. The more soil within the profile that is inundated, the less oxidation occurs. Growers have already made important changes by including rice in their sugarcane rotations, increasing use of summer floods, and growing crops at higher water tables. These techniques help control subsidence and permit more water storage in the EAA. On-going research to breed and select sugarcane cultivars adapted to higher water tables is underway.

The quality of drainage water released from the EAA to the WCAs, including Loxahatchee National Wildlife Refuge (LNWR), is another significant issue. Phosphorus runoff and the resulting imbalance in nutrient concentrations and vegetation growth have received more attention than other EAA-related issues. Two major programs are in place to lower the phosphorus content of EAA drainage water: (1) use of Best Management Practices (BMPs), innovative farming practices which significantly reduce nutrient loads from farms; and (2) design of up to 40,000 acres of stormwater Treatment Areas (STAs). The STAs will be large constructed wetlands that will receive stormwater runoff from the EAA and provide water quality treatment through natural processes before the water enters the WCAs. The amount of phosphorus that can be released to the Everglades and sustain a balanced system is controversial and still to be determined with relevant research ongoing.

RESTORATION OBJECTIVES:

Tractor in the fields
Tractor application of fertilizer directly to roots
of plants helps to reduce phosphorus runoff in soil.

b. 1996 Accomplishments

Everglades Forever Act/Everglades Program

Reduced phosphorus leaving farms by more than 68 percent for the 12-month monitoring period from May 1995 to April 1996 through the implementation of on-site phosphorus-reduction practices. The three year average reduction is approximately 45

Completed detailed design for STA-6, Phase 1, an 81 2-acre constructed wetland to remove phosphorus from agricultural stormwater before delivering to WCA-3A. This STA is being designed to treat an average volume of 15,000 acre-feet per year.

Completed a study in the ENR Project to quantify the effects of changing water levels and fish abundance on wading bird foraging. Experiments were performed in the 0.5-acre experimental test cells. Data from these experiments will be used in setting minimum flows and levels for the Everglades.

Completed development and preliminary calibration of the South Florida Water Quality Model (SFWQM), including linkages to the South Florida Water Management Model (SFWMM). The SFWQM will be used to evaluate the effects of C&SF Restudy options, as well as other water management actions, on the fate and transport of nutrients in the Everglades Protection Area. The model will also be used to identify permissible upstream phosphorus loads to maintain threshold phosphorus concentrations.

Completed a research study that identified and quantified the effects of nutrients and water levels on growth and survival of cattail and sawgrass seedlings. These data will be useful for evaluating hydropattern restoration projects.

Implemented a BMP Make-up Water Rule. Under this rule, water is delivered from Lake Okeechobee to the Everglades Protection Area to make up for annual flow reductions that result from implementation of BMPs in the EAA.

Completed preliminary research showing that EAA growers may have the capability to remove up to 1 million more pounds per year of phosphorus from the 28 Everglades. It may be feasible through genetic research to produce sugarcane cultivars that could eventually play an even greater role in phosphorus removal.

Technical Assistance to Agriculture

Began a wind erosion study to quantify and assess the impacts associated with wind-blown particulates from organic soils of the EAA that occur when soils are exposed during crop harvesting. Products of this study will be the development of a wind erosion prediction tool and assessment of potential impacts to air and water quality.

Bolles and Cross Canal General Reevaluation Report

Completed topographic surveys and geotechnical field work for the Bolles Canal.

Completed hydrologic modeling of existing conditions to determine the extent of water management problems in the basin.

Aerial view of test cell
Everglades Agricultural Area Test Cell

c. 1996 Initiatives

Technical Assistance to Agriculture

Accelerated the application of conservation technical assistance to agricultural growers in the Everglades Agricultural Area (EAA) and C-139 Drainage Basin to improve, conserve, and sustain natural resources. Initiated work with 29 private landowners that farm on 32,637 acres in those areas. As a result, landowners are implementing conservation practices and BMPs which are having positive impacts on water quality, water quantity, soil stability, air quality, and wildlife habitat contributions.

Everglades ForeverAct/Everglades Program

Initiated a 3-year research study to improve our understanding of the mechanisms of cattail and sawgrass growth and reproduction in the Everglades. This work will furnish data for calibrating the Everglades Landscape Model (ELM) and will be useful for evaluating hydropattern restoration alternatives.

Initiated construction of a greenhouse facility for Everglades research on the Florida Atlantic University campus. This research facility will be used to conduct experiments to address management questions concerning phosphorus threshold concentrations and minimum water flows and levels needed to support the Everglades plant and animal communities.

Initiated a cooperative five-year mercury research program in the Everglades. This program will identify and quantify the processes that govern mercury transport, transformation, and accumulation in the Everglades canals and marshes. The results will be used to support development of mathematical models for evaluating the impacts of various restoration scenarios on mercury transport and accumulation.

Initiated a 3-year study to quantify exchanges of mercury between air and water in the ENR Project. Results from this study will aid in completing a more accurate mercury mass budget for the ENR Project and in identifying potential mechanisms for more rapidly purging mercury from the Everglades.

Initiated a demonstration project to evaluative effectiveness of phosphorus removal by microfiltration.

Everglades Agricultural Area Test Cell

Initiated detailed design for STA-5.

Initiated detailed designs for STA-2 and STA-1W pumping stations.

Bolles and Cross Canal General Reevaluation Report

Initiated development of crop/flood duration damage relationships for the EAA.

d. 1997 Goals

Bolles and Cross Canal General Reevaluation Report

Complete economic evaluation of existing conditions and develop and analyze alternatives to address water-related problems in a manner that is consistent with and supports ecosystem restoration.

Everglades ForeverAct/Everglades Program

Initiate construction of STA-1 West.

Complete detailed design and initiate construction of STA-5.

Complete construction of STA-6, Phase I.

Initiate construction of STA-2 and the WCA-2A hydropattern restoration project.

Complete detailed design and initiate construction of STA-6, Phase 2, an additional 1,862-acre constructed wetland to treat runoff from the C-139 Basin and the C-139 Basin Annex before releasing to WCA 3A.

Install a new Mercury Deposition Network site within the ENR Project under the National Atmospheric Deposition Program. This will be used for collecting bulk atmospheric deposition data.

Design and construct a chemical treatment - direct filtration pilot facility in the Everglades Nutrient Removal Project. This pilot facility will be used to demonstrate and optimize this water treatment technology as a candidate for basin-scale use to reduce phosphorus loading to the Everglades.

Initiate design and construction of a demonstration-scale periphyton STA in the southern part of the EAA, near the future site for STA-3/4.

Technical Assistance to Agriculture

Initiate a study to assess the dynamic nature of the organic soils of the EAA. Specially, these observations will be made in terms of organic accretion which could provide potential benefits to atmospheric carbon sequestration. This study will determine what farmers who engage in installation of conservation practices and BMPs will have on securing sustainable agriculture by protecting their soil resource, but also maintaining a long-term carbon link for global climate change.


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