Setbacks and Buffers

Introduction to Setbacks and Buffers

In the coastal context, a setback is generally the required distance a structure must be located behind a baseline, like a tidal line (e.g., mean high or low water) or various types of natural features (e.g., a coastal dune, wetland, or floodplain).^{See footnote 1} Setbacks are typically designed to keep development away from portions of a property that are subject to coastal threats like flooding or erosion.^{See footnote 2} 

Setbacks are often specific to or tailored for individual properties whereby governments apply any combination of three common factors, as specified in the relevant law or regulations: (1) the size or square footage of a proposed development or structure; (2) the location of a baseline relative to the proposed development or structure; and (3) the level and severity of the physical risk facing that structure over a given time period (e.g., the lifespan of a structure). Nonetheless, governments can also implement standard setback distances for every property to which the requirement applies.

Similar to setbacks, buffers or buffer zones require landowners to leave parts of their property undeveloped to preserve them and their important natural functions.^{See footnote 3}  Governments commonly use buffers to prohibit property owners from building structures on or immediately adjacent to wetlands and coastal dunes.^{See footnote 4} 

Setback and buffer requirements vary and are usually implemented via state and local coastal, environmental, and natural resources laws and regulations and local land-use and floodplain ordinances. 

Setbacks and Buffers in a Managed Retreat Context

With setbacks and buffers, state and local governments can require property owners seeking a development (or redevelopment) permit to site structures and infrastructure away from vulnerable coastal areas, while simultaneously conserving important habitats and natural resources. Most setbacks and buffers will cover areas and be designed in ways that serve a dual or reciprocal benefit to protect people and the structures behind it, in addition to protecting the natural features they are conserving; however, the purpose and ecosystem benefits of some setbacks and buffers may be different based on location or type of physical risk. For example, setbacks and buffers could be used to site development away from highly erosive shorelines or intertidal areas that will be lost in the future and/or higher ground or adjacent tidal areas that can facilitate inland wetland migration. 

To support managed retreat efforts, setbacks and buffer distances can factor in future sea-level rise and erosion rates, but to do so requires significant investment in data collection and science to determine the rates that will be used to best achieve regulatory objectives. Governments may also have to evaluate and amend setback and buffer requirements, including what serves as the baseline, as physical conditions change over time (e.g., the rate of sea-level rise or erosion accelerates). For example, governments could consider setting fixed or permanent baselines for setbacks and buffers — for which no future development could occur seaward of that baseline — or move a baseline landward, as desired in response to local needs or concerns. From an administrative perspective, periodic updates to baselines can require lengthy and staff intensive regulatory processes. In comparison, dynamic baselines that, by law, are allowed to migrate landward (or seaward) with shifting coastlines and would not require a statutory or regulatory change can create more flexibility for agencies and potentially serve as a more effective climate adaptation strategy. 

Setbacks and buffers allow governments to facilitate managed retreat in a way that can enable people to stay on their properties longer. These tools are likely to be more feasible and a regulatory option in rural areas or communities with more land and larger lot sizes where setbacks and buffers can be implemented without preventing all development on a given parcel.

Policy Tradeoffs of Setbacks and Buffers

Legal Considerations for Setbacks and Buffers

The primary legal considerations concerning setbacks and buffers will relate to constitutional takings and environmental and natural resources statutes and regulations at the state and local levels. 

Jurisdictions can design setbacks and buffers to withstand potential regulatory takings challenges. The Fifth Amendment of the U.S. Constitution and analogous provisions of state constitutions prohibit governments from “taking” private property without just compensation.^{See footnote 5} While there are different types of takings, courts apply a “per se” test to physical occupations^{See footnote 6} and regulations that deprive a private property owner of all or essentially all of his/her property’s economic value;^{See footnote 7} however, in a managed retreat context, most setback and buffer regulations designed to protect people, property, and the coastal environment will be evaluated under a case-by-case-specific balancing test.^{See footnote 8} Generally, governments can use setbacks and buffers to restrict or limit development in vulnerable coastal areas and floodplains, so long as a property maintains some economic value and a regulation serves a legitimate public interest, such as safety or to offset ecological impacts resulting from use of private property. 

Governments can avoid or mitigate potential takings risks by ensuring that setback and buffer requirements are informed by science and plans. At a minimum, governments should: clearly justify the need for setbacks and buffers based on best available science; articulate the purpose for these requirements in planning and other documents that put affected private property owners on sufficient notice; and design and implement them on a spatial scale that is proportionate to the coastal hazard being mitigated. For more information on takings and recommendations to minimize legal risk, see the Crosscutting Legal Considerations>Takings section of this toolkit. 

In addition to takings, governments should also evaluate how setbacks and buffers may intersect with other environmental and natural resources laws and regulations, particularly under the federal Clean Water Act^{See footnote 9} and complementary state and local laws that protect wetlands and open space areas. By comprehensively viewing these types of laws in a managed retreat context, policymakers can avoid potential conflicts between laws and agencies by assessing where there are synergies to promote coastal conservation in a changing climate. 

Practice Tips

When implementing setbacks and buffers in a managed retreat context, decisionmakers may consider the following practice tips to address and balance different legal and policy tradeoffs: 

• Invest in data at an appropriate scale: Physical impacts from sea-level rise, storm surge, different types of flooding (e.g., precipitation), and coastal erosion are the impetus or drivers for state and community decisions to retreat. Accordingly, governments will need the best available scientific data and information on an appropriate scale to effectively develop and implement setback and buffer requirements. The types of data that policymakers typically have to invest in to establish setback and buffer requirements include sea-level rise and erosion rates, shoreline conditions, and the location and movement of coastal habitats like wetlands and forests. Collecting and compiling this data into resources that enable regulatory decisionmaking can be complex and expensive; however, governments can turn to federal agencies, universities, and other nonprofit partners to minimize these administrative and economic costs.
  
  While scientific data is important, community residents — particularly those who have lived in an area for a long time or have historical or cultural ties — can provide additional types of data or information based on historical or lived experiences that, among other things, can help governments better understand cyclical or long-term changes on the coast to inform climate adaptation discussions. Governments, therefore, should aim to make data collection processes as comprehensive as possible and reach out to more than just scientific and coastal experts. Complementary datasets will be key to crafting well-rounded, interdisciplinary approaches for managed retreat. 

• Engage communities: Governments should engage communities in the development and design of setback and buffer requirements. By engaging residents throughout the entire planning and regulatory implementation process, governments may be able to avoid or mitigate potential legal challenges by proactively seeking and addressing public concerns and conflicts. Plans documenting the consideration and justification for setbacks and buffers can serve as legal and policy guidance that puts residents “on notice” of regulatory decisions that may impact private property rights. In light of potential takings litigation, courts often evaluate whether local governments provided adequate notice to private property owners as one factor to assess whether a takings has occurred. Specifically, courts generally view public notice as one factor, among others, favorable to governments in finding that a takings has not occurred. This can also produce an administrative record that can show the reasons and justifications underlying a municipality’s retreat decisions (e.g., to protect lives and property). A strong and factually supported administrative record can also aid governments in potential legal challenges. For more information on takings, see the Crosscutting Legal Considerations>Takings section of this toolkit. 

• Evaluate how setbacks and buffers can be combined with other legal and policy tools for managed retreat: State and local governments can consider coupling setbacks and buffers with other planning and regulatory tools to implement more comprehensive retreat strategies that support one another. In particular, coastal, hazard mitigation, transportation, wetland migration or ecosystem-specific, and local comprehensive plans are of special relevance for justifying and coordinating decisions around setbacks and buffers. Moreover, other regulatory tools, like zoning and overlay zones, could be layered to implement setback and buffer requirements over an appropriate spatial scale, for example in less dense areas prioritized for wetland migration or in a community’s most vulnerable, highly erosive coastal areas. Setbacks can also be combined with development permit conditions to remove or relocate structures. For example, a permit could provide that a future state or local approval to rebuild a structure may be denied if the shoreline becomes inundated and erodes as a result of sea-level rise and increasing erosion, such that the planned development can no longer comply with setback requirements. In this way, a setback and development permit condition could allow development now, while also putting property owners on notice as land is lost to sea-level rise and erosion. This advance notice provision may also mitigate potential takings liability. 

• Align setback and buffer requirements with related programs and plans: Local governments should strive to align setback and buffer requirements with other state and local plans and initiatives — especially state and local coastal and hazard mitigation programs, state and regional transportation plans, and local land-use and zoning plans and ordinances. This alignment will better ensure cross-governmental and agency coordination to enhance effective managed retreat and project objectives and avoid conflicting policies or decisions. For example, transportation departments with long-range planning timeframes can be informed of setback requirements that could impact the siting of future roads. Impacted roads could instead be sited behind setbacks and/or possibly elevated to facilitate changing shorelines and migrating coastal habitats. In addition, alignments can support mutual agency and environmental and social/equity benefits and reduce administrative and economic costs. For example, by implementing higher regulatory standards to protect coastal wetlands and flood buffers, municipalities participating in the Federal Emergency Management Agency’s Community Rating System could potentially earn points to receive flood insurance discounts for their residents.