ANNUAL CONGRESS 2025

Using Residential Density Regulations to Manage Coastal Flood Risk: How Local Governments Manage New Housing Development in Flood Zones

Not scheduled

20m

Yildiz Technical University, Istanbul

Oral Track 05 | ENVIRONMENT AND CLIMATE

Speaker

Dr Evangeline Linkous (University of South Florida)

Description

Coastal areas have long been important to human settlement due to access to trade networks and food. Today, approximately 40% of the world’s population lives in coastal areas—an estimated 2.15 billion people. Along with residential development, coastal areas are home to highly developed infrastructure systems and trillions of dollars in private property assets. In the face of sea level rise and climate change, local governments employ a variety of coastal planning strategies.

This research uses a case study of Florida to examine the way local governments regulate residential density in the places where people, property, and infrastructure are most at risk from storm surges. Such policies may be used as part of broader coastal planning frameworks. The research looks at both the variety of approaches used by local governments to manage housing development in flood zones and assesses whether density is an appropriate tool for planning for storm surge.

Under Florida Statutes, Coastal High Hazard Areas (CHHA) are defined as the area below the elevation of a Category 1 storm surge line and are those places most likely to be significantly damaged or submerged by sea water. Florida requires that local governments designate CHHA areas within the local comprehensive plan and limit CHHA development in accordance with the hurricane evacuation capacities supported by local transportation infrastructure. Although Florida’s CHHA rules have changed over time, the overall intent has been to limit development in the CHHA for the purpose of maintaining evacuation capacity and minimizing loss related to public infrastructure and other public expenditures (Puszkin-Chevlin and Esnard, 2009).

Many Florida communities have long-established policies prohibiting additional residential density in the CHHA, resulting in zoning codes that are “frozen in time” (Puszkin-Chevlin and Esnard, 2009, 36). This led to concerns about the abilities of some communities to accommodate projected population growth, support economic development, and provide affordable housing. These concerns were amplified following a 2016 update to the Florida Sea, Lake, and Overland Surges from Hurricanes (SLOSH) model used to identify the CHHA. In many communities, the update resulted in a significant expansion of the CHHA. For example, the City of St. Petersburg faced a 41% increase in the CHHA following the 2016 model update; this in turn resulted in text amendments to their Comprehensive Plan in 2020 that shifted from a strict prohibition of new development in the CHHA to a criteria-based project evaluation approach.

The research includes two phases. In phase one, a survey of local government comprehensive plans that include Coastal Management Elements was conducted to identify policies for addressing new density in the CHHA. Policies were analyzed to identify major approaches, such as those that strictly limit new density, those that incorporate incentives such as transferable development rights that direct density to specific areas, and those that use criteria such as building code or hurricane evacuation standards to permit density increases. For this phase, data collection is complete and analysis is underway. To date, I have identified five approaches to residential density regulation in the CHHA which range from not allowing any density increases to allowing density increases only if certain criteria are met. The criteria approach aims to balance considerations about existing infrastructure investments and community redevelopment planning but places new residents at increased risk.In phase two (currently underway), case studies of at least four Florida communities will be conducted to examine the decision-making context informing different policy approaches.

Florida’s experiences provide instructive, transferable lessons on the balancing act involved between protecting human lives and public assets, preventing climate gentrification, and accommodating demand for housing and redevelopment near existing urban infrastructure.

References

Butler, W., Deyle, R., and Mutnansky, C. (2016). Low-regrets incrementalism: Land use planning adaptation to accelerating sea level rise in Florida’s coastal communities. Journal of Planning Education and Research, 36(3): 319-332.

Holmes, T. and Butler, W. (2021). Implementing a mandate to plan for sea level rise: top-down, bottom-up, and middle-out actions in the Tampa Bay region. Journal of Environmental Planning and Management, DOI: 10.1080/09640568.2020.1865885

Markell, D. 2016. Emerging Legal and Institutional Responses to Sea-Level Rise in Florida and Beyond. Columbia Journal of Environmental Law, 42, 1-58.

Murley, J., Puszkin-Chevlin, A., Esnard, E., Kalin, R., Matthews, M., and Grooms, A. (2008). Assessment of Redefining Florida’s Coastal High Hazard Area. Florida Atlantic University Center for Urban and Environmental Solutions.

Puszkin-Chevlin, A. and Esnard, E. (2009). Incremental evolution and devolution of Florida’s Coastal High Hazard Area policy. Journal of Environmental Planning and Management, 52(3), 297-313.