About the GSI Design Process
When it rains, most of us don’t think about where the water goes—until the water has nowhere to go. When rainfall overwhelms our stormwater drainage infrastructure capacity, flooding occurs. One way to address flooding is through capturing and infiltrating stormwater onsite using green stormwater infrastructure (GSI).
The foundation of GSI performance is soils. Soils characteristics establish infiltration rate – how fast water enters and is absorbed by the soil. Water infiltration is important, as water that Is not infiltrated into the ground causes runoff and flooding. The more infiltration, the less flooding.
This guide is designed to support you in integrating soils research into GSI planning. It answers questions such as:
- What steps are necessary to understand soils and conduct soils fieldwork?
- Once you have soils data, how can you integrate it into GSI design?
- How can you bring collaborative engagement to the project?
- What actions can you take to advance the project—are you ready to implement, or is more work needed to address project barriers and specific community needs?
Design Process Steps
Steps for integrating soils research into green stormwater infrastructure planning:
- Use an engagement process to build bridges between community members, stormwater professionals, and university researchers.
- Investigate native subsoils by collecting existing soils data to inform site location and conducting fieldwork to collect soils samples for a site soils analysis.
- Connect soils characteristics with GSI design; to size, scale, and estimate runoff reduction.
- Implement GSI, including final design specifications (such as choosing plants), costs and funding, and installation and maintenance.
Commitment to GSI
Community engagement is a critical avenue through which to build initial and ongoing commitment to GSI. During the community engagement step, barriers to commitment may be identified that need to be addressed prior to moving forward. Fortunately, the research and on-the-ground experience for overcoming these barriers and promoting GSI adoption is evolving quickly.
Note: this GSI design process does not directly address the critical question of achieving community commitment. No community is likely to have the capacity to fully implement all the community engagement tasks outlined in this GSI design process.
This design process was developed through a project that included two pilot communities in Chicago’s Calumet region that had the goal of integrating soils performance into GSI design. Illinois Groundwork is grateful to them for their participation.