Achieving success on both the programmatic and project scale depends on the development of strong policies, guidance, and tools to support green infrastructure implementation in the right-of-way.
Whether motivated by federal regulatory requirements for water quality and CSOs, or by local sustainability or climate action plans, green stormwater infrastructure should be incorporated into city policies and plans at a range of scales to address stormwater management on both public and private property.
Impervious Surface by Use and Location
- Streets and Public ROW (35-40%)
- Industry and Commercial (15-20%)
- Homes (20%)
- Open Space (10%)
- Other uses: Schools and Public Facilities, Alleys/Driveways, Parking
The proportion of impervious surface by use and location may vary by city, but across the US, a substantial proportion of impervious surface in the city is publicly owned, whether as part of the ROW or on publicly owned land. However, many existing policy levers are focused on privately owned properties and can be used in conjunction with green street projects.
Complete Streets Policy
Many cities have addressed the inclusion of GSI practices through the adoption of Complete Streets policies that specifically require greening practices. Cities may include green infrastructure in their project development process, including as part of a Complete Streets checklist.
Applies to:
Streets & Public Row (35 – 40% of impervious surface)
Green Streets Policy
Some cities have adopted specific Green Streets policies that include goals and processes for capturing and infiltrating stormwater at transportation facilities.
Applies to:
Streets & Public Row (35 – 40% of impervious surface)
Green Street Design Standards
Cities may take complete street design and green street principles a step further by developing a green infrastructure design toolkit specifically catered to local street contexts. Green street design manuals and provide detailed strategies for merging multi-modal design with ecological performance.
Applies to:
Streets & Public Row (35 – 40% of impervious surface)
Local Standards & Guidance
The adoption of standard drawings, stormwater manuals and design guidelines have been a critical step in the advancement of GSI implementation in the right-of-way.
Local design guidelines provide recommendations for implementing green practices in street projects. Integrating stormwater management into project development and review, including in Complete Streets design guides or checklists, codifies goals and responsibilities for implementing green infrastructure.
Stormwater manuals have also been instrumental in compliance with regulatory and policy requirements. Design manuals can codify detailed local knowledge and best practices into a rigorous toolkit, and may include sizing and modeling criteria, preferred vegetation and media, and maintenance strategies.
Adopting standard GSI drawings as part of a cityâs standard drawing set ensures planning, design, and construction are in alignment among agencies, project goals, and construction standards.
Applies to:
Streets & Public Row (35 – 40% of impervious surface)
Open Space (10%)
Alleys/Driveways
Stormwater Code/Regulations/Ordinance/Zoning
Most cities have codes, regulations, and ordinances that regulate stormwater runoff. Policies remove obstacles and create incentives for reducing stormwater runoff on both private property and public rights-of-way.
Applies to:
Alleys/Driveways
Parking
Industry / Commercial (15 – 20%)
Homes (20%)
Development Fee/Incentive
Development incentives are offered to private developers who proactively use enhanced sustainable and green building and site design practices. These incentives can provide not only site-level benefits but neighborhood benefits as well, adding green features and placemaking amenities. Additionally, developers have an opportunity to realize potential tax credits, expedited permitting, or a floor area ratio bonus, depending on the structure of the incentive.
Applies to:
Industry / Commercial (15 – 20%)
Stormwater Fee Discount/Credit
Stormwater fee discounts and credits are offered to property owners to reduce impermeable surface or use GSI practices to reduce stormwater runoff. Cities and jurisdictions that levy stormwater utility fees may offer discounts to incentivize on-site stormwater management.
Applies to:
Industry / Commercial (15 – 20%)
Homes (20%)