Blue-Green Infrastructure (BGI) blends nature and engineering to manage stormwater sustainably in cities. It reduces runoff, improves water quality, and boosts climate resilience, all while offering added ecological and social value for urban communities. Read how Philadelphia is leveraging stormwater credit trading to expand BGI adoption and build a more resilient urban water system.
Nature-Based Design in Blue-Green Infrastructure
BGI uses green spaces and water-smart features that mimic natural water cycles. Elements like green roofs, permeable pavements, bioswales, and wetlands capture and clean stormwater before it reaches drains. Unlike grey infrastructure, BGI encourages water to soak in and evaporate, helping prevent floods and pollution. It also boosts biodiversity, cools cities, and makes urban areas more livable.
Scaling Up Blue-Green Infrastructure Across Cities
Expanding BGI citywide needs investment on both public and private land. Cities often add BGI to parks, roads, and buildings, but private owners also play a key role. Tools like stormwater credit trading offer financial incentives, encouraging wider adoption of green practices for better stormwater control.
Stormwater Credits Drive Private Investment in BGI
Stormwater credits reward property owners for managing runoff on-site with lower utility fees. These savings motivate private investments in BGI, supporting broader efforts to manage water sustainably across urban areas.
Stormwater Fee Credits Support Citywide BGI Efforts
Cities with stormwater fees offer credits to properties that adopt BGI, easing pressure on public drainage systems. Property owners can qualify by adding permeable surfaces, directing runoff to green spaces, or installing features like green roofs, bioswales, and rain gardens. These credits lower costs while helping cities prevent sewer overflows and protect water quality.
Maximizing Impact Through Well-Supported Stormwater Credit Programs
Stormwater credits work best when BGI is well-designed, installed, and maintained. To support this, many cities offer grants, expert guidance, and online tools to connect owners with trusted vendors. By tying incentives to real environmental results, these programs speed up BGI adoption, cut flood risks, and build lasting climate resilience.
Case Study: How Philadelphia’s Stormwater Credits Program Boosts BGI Adoption and Urban Resilience
The Stormwater Credits Program by the Philadelphia Water Department (PWD) provides financial incentives to property owners who implement on-site stormwater management solutions. Designed to reduce stormwater charges for non-residential, condominium, and multi-family residential properties, the program encourages sustainable practices that minimize runoff and relieve pressure on city infrastructure.
Eligible properties can receive credits under several categories:
- Open Space Credits apply to properties with natural pervious surfaces, such as lawns or wooded areas, that allow water to infiltrate the soil.
- Impervious Area Reduction Credits reward property owners who redirect runoff from hard surfaces like roofs and sidewalks to grassy or vegetated areas.
- Managed Impervious Area Credits apply to properties using BGI, such as rain gardens, porous pavement, or green roofs.
- Additionally, properties with a valid National Pollutant Discharge Elimination System (NPDES) permit can qualify for an NPDES Credit, recognizing compliance with industrial stormwater regulations.
PWD offers the Stormwater Grants Program to support stormwater management efforts further, providing funding for voluntary BGI retrofits. Property owners seeking to install BGI solutions can use Stormwater Connect, a digital matchmaking platform that links them with experienced vendors. Additionally, proper maintenance of BGI is required to retain stormwater credits, and PWD provides guidance through a BGI Maintenance Guidance Manual and a list of recommended contractors.
By reducing financial barriers, the Stormwater Credits Program incentivizes long-term investments in BGI, helping property owners manage costs while contributing to a more resilient urban water system.
The Take-Out
Stormwater credit trading accelerates private investment in BGI, making urban water management more sustainable and cost-effective.