Capture Stormwater

We can reduce stormwater volume and the amount nitrogen that reaches waterways by installing grassed channels, vegetated swales, or bioswales sometimes known as Green Stormwater Infrastructure (GSI). These are open-channels that direct runoff to areas where water can soak into the ground. In urban settings, bioswales are often located along sidewalks in public right of way areas. Swales and rain gardens treat very small drainage areas (five acres or less) and have the added benefit of capturing bacteria in stormwater.

Nitrogen Removal

  • 25-40%

Cost Efficiency

  • Bioswale: $139 per pound of nitrogen removed

Project Costs

  • Bioswale Average Material and Installation Cost: $11,000
  • Operations and Maintenance: $200-$300 per year


  • GSI is inexpensive compared to grey infrastructure
  • GSI reduces stormwater volume and rate of flow in municipal systems
  • GSI can filter out nutrients and other contaminants from stormwater
  • They add to green space and are aesthetically pleasing
  • Rain gardens and bioswales are easily scalable


  • GSI requires specific site requirements, such as space in the right of way
  • GSI requires regular maintenance by some entity
  • The nutrient retention of GSI is still unknown
  • Difficult to quantify and monitor effect of GSI on water quality
  • May require adoption of stormwater regulations