Stormwater Management Zoning Study

This study proposed amendments to existing zoning standards applicable to public stormwater management facilities to enable greater flexibility in their siting and construction.  In addition, the Public Spaces Master Plan recommends modernizing zoning standards for more flexible public space master planning and development. The amendments were adopted in March, 2023. 

Study Background

The County is working to improve flood resilience in response to increasingly intense storms and flooding.  The Flood Resilient Arlington strategy involves adding capacity to the system with stormwater facilities on public land. 

• Locations may include parks and schools, if those locations are well situated to help reduce flood risk in a particular watershed.
• DES is primarily exploring the use of underground detention facilities, underground vaults, overland relief measures, and surface detention facilities to meet these needs.  Many of these facilities could have open space or fields over them after construction.
• All DES capital projects include a robust public engagement process, following the County’s public engagement guide for capital projects.   The potential updates to the zoning ordinance would not diminish that extensive public engagement for stormwater facility projects.

Land use regulations that differentiate how stormwater management can be accomplished based on zoning districts complicates the County’s ability to effectively manage stormwater runoff.

• Similarly to other public utility needs for clean water, sewage removal, and electricity transmission, the need for effective stormwater management is incumbent and present in all zoning districts and for all types of land use.
• Currently, the zoning ordinance restricts minor utilities in public districts (i.e., S-3A), and requires a use permit for major utilities. These restrictions are unique to the public districts, as minor utilities are permitted by-right, without County Board use permit approval, in residential, commercial/mixed use, and industrial districts.

Zoning requirements for setbacks create additional complexity in planning for, constructing and accommodating stormwater management facilities within parks and public spaces for maximum public benefit. 

• The zoning ordinance regulates the location of most types of buildings and structures through standards which require such features to be located a minimum distance from either street centerlines or property boundaries.  Setbacks are intended to regulate the positioning of buildings and structures and are not as applicable to utilities and park areas.
• Public space amenities, such as sport court fences and seating, are subject to regulations which restrict their maximum height and placement in a manner that has unreasonably complicated past park development processes.

• This is envisioned as one of multiple zoning study processes that interdepartmental staff will conduct to implement PSMP recommendations and modernize zoning standards to achieve more flexible public space master planning and development.

  Study Goals

• Improve Consistency: The Zoning Ordinance treats stormwater systems in publicly zoned districts (ex., parks, schools) differently when compared to how other zoning districts treat water utilities.

• Add Flexibility:  The current zoning standards do not readily enable the use of certain stormwater system components. The County would benefit from modernized zoning standards for more flexible public space master planning and development. As Arlington continues to grow, community needs and uses are changing and zoning regulations may need to be updated to respond to community needs for resiliency planning and park space.

Planning Foundation

Stormwater Master Plan (2014, page 5)

• Strategy 1—Reduce flooding risks to public and private property 
• Strategy 2—Maintain and upgrade stormwater infrastructure
• Strategy 9—Initiate climate adaptation and resilience planning

The Public Spaces Master Plan (PSMP) adopted in 2019, recommends reviewing and considering updates to the County’s zoning regulations related to parks and public spaces in “S-3A” and “P-S” districts, and other County codes as needed  (page 68).

• Parks areas along stream valleys have RPA and floodplain restrictions in addition to zoning setback regulations
• There is a public need to add parks to respond to population growth and meet community needs
• Updating zoning regulations could enable greater flexibility for the location of park amenities/features so that park planning/development can take the fullest advantage of innovative designs and best practices

Engagement Timeline