Hazards Planning Center

Subdivision Design in Flood Hazard Areas

The subdivision of land in or near floodplains involves the potential creation of tomorrow's flood risks. In an era of increasing attention to climate change, those risks may be greater than they have been in the past.

APA has a long history of addressing these issues, dating back at least to its 1997 publication of Subdivision Design in Flood Hazard Areas (PAS Report No. 473, 1997).

Now, in partnership with the Association of State Floodplain Managers, and with funding from the Federal Emergency Management Agency, we are revisiting the topic to provide updated guidance on the subject for local planners, consultants, and others involved in the subdivision design and site plan review process. The need is clear for much more technical guidance related to all aspects of subdivisions, from planning to design, to standards, to infrastructure maintenance.

The new PAS Report will benefit from a larger effort at partnership between APA and ASFPM on a number of fronts. Both organizations have been leaders in the NOAA Digital Coast Partnership. APA and ASFPM are partnering also on a new project called the Planning Information Exchange, funded under the same agreement with FEMA, to provide educational webinars on hazard mitigation planning. And we are exploring other areas as well that we consider grounds for potential fruitful collaboration. Planners and floodplain managers have many common goals, and our two organizations even have some overlapping membership. Both bring valuable expertise to this project.

What We Will Produce

  1. A new PAS Report whose focus would be broadened from the strict subdivision approach used in PAS Report No. 473 to include other land-use regulatory considerations affecting design in flood hazard areas, specifically including PUD regulations and design review, but also innovations in coastal and floodplain zoning and regulation.
  2. Web-based enhancements to expand the outreach potential of the project. Examples of web-based resources would include an inventory of the best sample ordinances, checklists for regulatory consideration, an annotated bibliography, and a glossary. In the past, some of these might have been included in a printed PAS Report, but in recent years APA has adopted the practice of placing these resources online in order to make them more accessible while also producing a slimmer, more accessible printed report. A downloadable PDF version of the report will also be made available.
  3. Professional training opportunities based on the report's findings, such as presentations at the national and state chapter conferences of both partner organizations managing the project. APA and ASFPM can also propose additional derivative products for FEMA consideration toward the end of the project, if desired. APA and FEMA have collaborated on such derivative products in connection with two other APA projects in the last five years.

Why This Project?

Obviously, much has changed since APA's PAS Report 473, Subdivision Design in Flood Hazard Areas, was published in 1997. The Community Rating System  was then still in its infancy, having only been developed in 1990. Sustainability and resiliency were just words found in the dictionary and not necessarily a focus of land development. No one had given much thought to adapting to our ever-changing climate. Project Impact was launched the same year, and the National Flood Insurance Program was approaching its 30th birthday in 1998.

Almost 20 years later, sustainability, resilience, climate change, and related topics are at the forefront of attention for planners, floodplain managers, and related professionals. However, subdivision practices have seen relatively little change, especially where they concern comprehensive floodplain management. The benefit provided by this project relates to this basic need.

APA, the nation's lead organization in the planning profession, and ASFPM, the nation's premier floodplain management organization, are partnering to address the needs of the urban planning and floodplain management professions by providing modern-day assistance on "sound" subdivision guidelines and related regulatory practices such as planned unit development (PUD) design, emerging tools such as the coastal resilience zone, and issue areas such as climate adaptation and No Adverse Impact to name a few of the areas of emphasis.

The idea behind this update, in part, is to focus on breaking the build-damage-rebuild cycle our nation now finds itself in, to reduce risk from flood damages, and to incorporate best planning practice guidance, as well as other aspects of floodplain management. It is quite obvious that a community cannot be sustainable or resilient without safe places to live, work, and play.

One need merely look at the damage to the housing stock and the loss of life from Hurricanes Sandy and Katrina or events such as the Colorado flood of 2013 or the Atlanta flood of 2009, to see the need for and the practical utility of the proposed update to PAS 473. It is about saving lives and protecting property at its foundation and about building a future for our residential communities that are free from, or at least have a reduced risk to, flooding.


Symposium on Subdivision Design in Flood Hazard Areas

Symposium Summary

Symposium Participants

Literature Review