Executive Summary

Nearly thirty years ago the Florida Keys were designated as an Area of Critical State Concern. The state recognized that Monroe County contained many valuable natural, environmental, historical, and economic resources that required thoughtful management. In 1996, as a result of many years of discussion, negotiation, and litigation, the Florida Administration Commission issued an Executive Order requiring the preparation of a “carrying capacity analysis” for the Florida Keys. To fulfill this requirement, the U.S. Army Corps of Engineers and the Florida Department of Community Affairs jointly sponsored the Florida Keys Carrying Capacity Study (FKCCS). The key component of this study is a carrying capacity analysis model (CCAM) that provides a technical tool for state and local jurisdictions to “determine the ability of the Florida Keys ecosystem, and the various segments thereof, to withstand all impacts of additional land development activities.”

This National Research Council (NRC) report provides a critical review of the Florida Keys Carrying Capacity Study: Test Carrying Capacity Analysis Model, First Draft (URS Corporation, Inc., 2001a), hereafter referred to as the Draft CCAM. This independent review offers critical commentary in order to assist the sponsors and contractors in making final adjustments to their report and the Carrying Capacity Analysis Model. The committee (Appendix A) was charged with the task of reviewing the Draft CCAM and submitting their report within 13 weeks. Given the short timeline for this review, the committee was unable to comment on the inner workings of the model, examination of input data, or future data collection. The committee was able to present a thorough review of the Draft CCAM and the data and calculations presented in that document as re-



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A Review of the Florida Keys Carrying Capacity Study Executive Summary Nearly thirty years ago the Florida Keys were designated as an Area of Critical State Concern. The state recognized that Monroe County contained many valuable natural, environmental, historical, and economic resources that required thoughtful management. In 1996, as a result of many years of discussion, negotiation, and litigation, the Florida Administration Commission issued an Executive Order requiring the preparation of a “carrying capacity analysis” for the Florida Keys. To fulfill this requirement, the U.S. Army Corps of Engineers and the Florida Department of Community Affairs jointly sponsored the Florida Keys Carrying Capacity Study (FKCCS). The key component of this study is a carrying capacity analysis model (CCAM) that provides a technical tool for state and local jurisdictions to “determine the ability of the Florida Keys ecosystem, and the various segments thereof, to withstand all impacts of additional land development activities.” This National Research Council (NRC) report provides a critical review of the Florida Keys Carrying Capacity Study: Test Carrying Capacity Analysis Model, First Draft (URS Corporation, Inc., 2001a), hereafter referred to as the Draft CCAM. This independent review offers critical commentary in order to assist the sponsors and contractors in making final adjustments to their report and the Carrying Capacity Analysis Model. The committee (Appendix A) was charged with the task of reviewing the Draft CCAM and submitting their report within 13 weeks. Given the short timeline for this review, the committee was unable to comment on the inner workings of the model, examination of input data, or future data collection. The committee was able to present a thorough review of the Draft CCAM and the data and calculations presented in that document as re-

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A Review of the Florida Keys Carrying Capacity Study quired by the statement of task (below). (Note: This NRC Committee also provided an Interim Review of the Florida Keys Carrying Capacity Study [National Research Council, 2001] in March 2001 [Full text included in Appendix B]). The Draft CCAM is composed of several modules: Socioeconomic, Fiscal, Human Infrastructure, Integrated Water, Marine, and Terrestrial. These modules are designed to work together to evaluate the impact of further development in the Florida Keys. In addition, the Draft CCAM includes a Graphic User Interface (GUI) for a Scenario Generator, a tool that allows the user (through a series of menus) to specify different land use change scenarios, including new development, redevelopment of existing urban uses, and restoration of disturbed or developed land. The GUI enables the user to specify the type and intensity of land use change at scales ranging from individual parcels to whole-island planning units. Outputs from the Scenario Generator, generally reported at the planning unit scale, serve as inputs that drive other model modules. The GUI is a useful interface to the Draft CCAM. It appears to be appropriate and flexible. Though user-friendly, its present design does not allow the user to specify parameters (coefficients) within the individual modules. In addition, the GUI lacks a method to represent directly the impacts of tourism, or model the impacts of vested developments. These limitations result in uncertainties with regard to future population size, corresponding numbers of dwelling units, and commercial floor areas. The inability to estimate separately tourist populations also precludes modeling of the direct effects of tourist activities such as boating, fishing, and diving. These constraints, in turn, affect the model’s analysis of any future growth scenarios and limit the other modules’ utility. Two alternative scenarios—Current Conditions and Smart Growth—were tested in the Draft CCAM but neither was explained in detail. The Socioeconomic Module produces population estimates that serve as input for all the other modules. These estimates implicitly account for tourism, but the method used is too simplistic. In addition, the module produces no useful quality of life indicators. Although the Affordable Housing Index could be useful, it currently lacks a functional link to the user-defined land use change scenarios. The Fiscal Module produces some useful indicators of fiscal impact and seems ready for use with some adjustment. It lacks consideration of local/non-local cost sharing, costs of land acquisition, and tax losses, however. It also suffers from an assumption of constant demographic composition, which makes it unable to evaluate shifts in population patterns (e.g., a larger percentage of retired residents or school-age children). The Human Infrastructure Module deals exclusively with traffic impacts. It produces estimates of additional trips, level of service, and hurricane evacuation times. Level of service estimates are constrained by a lack of local trip genera-

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A Review of the Florida Keys Carrying Capacity Study tion coefficients. Hurricane evacuation clearance time estimates do not account for the spatial distribution of new development. The Integrated Water Module produces estimates of wastewater and storm-water generation and seasonal average pollutant loads to marine waters. While the marine loadings can be used to compare alternatives, they are not adequate to evaluate the effect on the near-shore marine environment. The Marine Module suffers from a lack of input information and should not be used to draw any meaningful conclusions on impact due to current or future development activities. This module lacks good data, leaves out important factors, and uses a dispersion model that is only appropriate for point source loading. It would need major revision in order to be useful within the context of the CCAM. Issues of terrestrial habitat and species richness appear to be reasonably well addressed by the Terrestrial Module. This module produces a number of measures of environmental impact, particularly with regard to a representative set of species (including endangered species). There are some important technical concerns that need to be addressed, however. The methods used are appropriate given the available science, but the results are imprecise. In some cases, the coefficients used in this module are inappropriate. The Draft CCAM does show great improvement over the version presented to the committee a little over a year ago. Nevertheless, several data and structure issues remain. Nomenclature and consistency in terminology continue to be a source of confusion to the reader. Several of the modules calculate various output measures using Census data from 1990 instead of 2000. Errors based on these old population figures resonate throughout the Draft CCAM. The usefulness of the model and integration of the modules are constrained by the lack of calibration and sensitivity testing. In addition, several of the modules lack direct statements regarding the uncertainty and the limitations of the data and analysis, yet output described in the text includes color coded maps that apply threshold values that imply a precision that simply does not exist. Many of the currently available models used in the Draft CCAM require that restoration, land acquisition for conservation, and conversion of septic tanks and cess pits to higher levels of treatment all occur immediately. All these actions require significant funds to implement but are nevertheless assumed to occur in the Draft CCAM. Results, therefore, cannot be used to draw conclusions about impacts from future development, and non-critical use of the CCAM may provide misleading results. In general, the Scenario Generator, Fiscal, Integrated Water, and Terrestrial Modules can be useful in estimating impacts to the Florida Keys with some relatively minor technical adjustments. As it exists, the Marine Module will require almost complete revision to be a functional part of the CCAM. The Socioeconomic and Human Infrastructure Modules also need major revision to remain useful parts of the CCAM. Detailed suggestions and recommendations

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A Review of the Florida Keys Carrying Capacity Study are provided for the CCAM as a whole and for each module in both the text and the appendices. The contractors did an admirable job of working with the data available. Time and money constraints aside, however, the task was perhaps too ambitious an undertaking for the data and level of knowledge that currently exist for Florida Keys ecosystems. In its present stage of development, the CCAM is not ready to “determine the ability of the Florida Keys ecosystem . . . to withstand all impacts of additional land development activities” as mandated by Florida Administration Commission Rule 28.20-100. Significant improvement of the CCAM is required in several key aspects if it is to be useful as an impact assessment tool. Endeavors such as the CCAM tend to obscure significant scientific uncertainty and project an unrealistic understanding of complicated environmental issues. What is needed and what the committee would like to express in this review, are expert opinion, common sense, and stakeholder consensus. The CCAM has important information to bring to the table, particularly where its modules have been based upon good and reliable scientific data. In the end, however, the decision to be made will be social not scientific. Once management has been implemented, science can make further progress toward understanding the natural system through modeling endeavors such as this one.