Portal de Periódicos da CAPES

The Proof of the Planning Is in the Platting: An Evaluation of Florida's Hurricane Exposure Mitigation Planning Mandate

2008; Taylor & Francis; Volume: 74; Issue: 3 Linguagem: Inglês

10.1080/01944360802229612

1939-0130

Robert E. Deyle, Timothy S. Chapín, Earl J. Baker,

Flood Risk Assessment and Management

Abstract Problem: Florida's 1985 Growth Management Act required the state's coastal communities to include policies for two types of hurricane hazard zones in their comprehensive plans: to direct populations away from coastal high hazard areas (CHHAs) and to maintain evacuation times within larger hurricane vulnerability zones (HVZs). State law requires local governments to initiate measures to implement these policies within one year of state approval of the local plan. Have communities complied with these state mandates? Purpose: This research aims to determine the extent to which post-plan residential development intensities within hurricane hazard zones conform to the state's policy mandate and the degree to which success in this regard can be explained by the quality of local plan maps and policies. Methods: We conducted graphical analysis of development trends, and undertook quasi-experimental analysis of pre- and post-plan residential development inside and outside CHHAs, as well as analyzing correlations between plan quality and post-plan residential development intensity. We also conducted interviews for case studies. Results and conclusions: We found residential exposure to hurricane flood hazards to have increased substantially in the majority of 74 municipalities and 15 coastal counties in Florida after the state approved local comprehensive plans. Residential development inside CHHAs did not slow after plans were adopted by most of these coastal communities. We found better maps and stronger policies to be correlated with lower post-plan development intensity, but the policy quality effect, though not the map quality effect, disappeared after controlling for pre-plan development intensities. These results may be due in part to vesting of development approved prior to adopting the plans, pre-existing zoning entitlements, and Florida's 1995 property rights law. Takeaway for practice: State planning mandates aimed at managing development in critical areas are likely to have only marginal effects because of prior entitlements and the legal and political inertia of existing local plan policies and land development regulations. Research support: Research support was received from the National Oceanic and Atmospheric Administration's Office of Sea Grant, the Florida Department of Community Affairs, and Florida State University's DeVoe Moore Center. Keywords: comprehensive plan implementationplan qualitystate planning mandateshazard mitigation policiesFlorida Notes ψ p < 0.10 * p < 0.05 ψ p < 0.10 * p < 0.05 ** p < 0.01 1. The Department of Community Affairs is the state agency that was tasked with reviewing and certifying that all local comprehensive plans meet the state's minimum standards. This process began in 1988, although most local comprehensive plans were certified in 1990 and 1991. 2. Hurricane intensity is typically measured using the five-level Saffir-Simpson scale based on wind speed and storm surge height. Category 1 hurricanes are characterized by wind speeds between 74 and 95 miles per hour and storm surge heights of 4 to 5 feet above mean sea level. A category 5 hurricane has wind speeds in excess of 155 mph and storm surge heights in excess of 18 feet. 3. Land use codes reported by county property appraisers in Florida for vacant parcels reflect the appraiser's judgment of highest and best use. Thus, they are influenced by the zoning of the parcel as well as uses of adjacent parcels. 4. In most Florida counties property appraiser parcel maps include separate "parcel" polygons for each condominium or cooperative unit to provide a geographic reference for their unique ownership. 5. This estimate is based on the proportion of total 2000 population in the 35 coastal counties that is accounted for by the 15 counties in our sample (36%). This extrapolation implicitly assumes that our sample is also proportionately representative of the spatial extent of CHHAs and HVZs throughout the state. 6. A total of 61 jurisdictions from our sample of 89 coastal communities have land both inside and outside a CHHA. We could not construct complete pre-plan data for 3 of those communities, thus the sample analyzed here is 58. An additional 16 communities are completely contained within their CHHAs, that is, they have no land outside their CHHAs. The remaining 12 communities have no land inside a CHHA, but have some land inside an HVZ that would be flooded by a category 3 hurricane. 7. The Mann-Whitney-Wilcoxon test (or simply the Mann-Whitney test or Wilcoxon test) is used with ordinal data, or data that are not normally distributed, to determine whether or not two independent samples can be assumed to come from the same population (CitationConover, 1980; CitationGarson, 2008). Ranks are assigned to each observation from the combined samples. The statistic tests whether the ranks of the individual observations are randomly distributed between the two samples. Shapiro-Wilk tests for each of the variables are significant at the 99.9% level, indicating that their values are not normally distributed. 8. Shapiro-Wilk test results were significant at the 99.9% level. 9. This transformation captures rank-order statistical relationships comparable to those employed by the Kendall's tau-b test. Although the rank transformation sacrifices information about the variable, loss of statistical power in regression is not usually a consequence, and the transformation generally ensures a normal distribution of error terms (CitationHettmansperger, 1978; CitationIman & Conover, 1979). 10. Copies of original comprehensive plans were obtained from the archives of the Florida Department of Community Affairs. We ascertained what the plan content had been in 2002 by comparing current comprehensive plan content with the original plans and, where the current plans contained different language, using the DCA library of comprehensive plan amendments to determine when relevant plan content was amended. 11. A Florida community's FLUM details the jurisdiction's desired land use mix and land use intensities over the planning horizon of the comprehensive plan. All local land development regulations, including zoning, as well as individual development orders, must be consistent with the land uses, densities, and intensities set forth in the comprehensive plan (CitationFlorida Growth Management Act, 1985c). While the comprehensive plan does not establish entitlements in the manner of the zoning ordinance (Citation Board of County Commissioners of Brevard County v. Snyder, 1993), the future land use element and FLUM define the parameters that must govern the zoning ordinance and other land development regulations. 12. We recognize that these models are not fully specified, as evidenced by the low adjusted R 2 values reported in Table 7. Although we have included constraints upon developable land (acreage in wetlands and CBRS units) and accounted for the amount of developable land in our dependent variable, ideally we would also control for variations in development costs (e.g., land costs and construction costs). However, these data were not readily available for the counties included in the analysis. We also acknowledge that our development demand proxies would not capture shifts in the location of development demand that may have occurred in the early 1990s. 13. All else equal, a community with the CHHA shown on their FLUM would exhibit a growth density rank 24 positions lower than one without it, while a difference of one point on the quality of the local policy directing populations away from the CHHA would lower a community's rank by roughly four positions. 14. Composite plan quality score was computed by averaging the plan scores for the original comprehensive plan and the 2000 comprehensive plan for each jurisdiction. These scores were derived from an aggregate of the assigned values for four plan items: CHHA definition, CHHA map, a policy for limiting public expenditures in the CHHA, and a policy for directing populations away from the CHHA. 15. We were able to assess development patterns after plan approval for evidence of vesting in the full set of 61 sampled jurisdictions with land inside and outside of a CHHA.