Green Infrastructure Design Guide

The San Francisco Bay Regional Water Quality Control Board’s Municipal Regional Permit (MRP) requires jurisdictions to transition from gray, or piped, infrastructure storm drainage systems to green, or landscape-based, systems that capture, treat, and infiltrate runoff — Green Infrastructure.  The County encourages project proponents to incorporate Green Infrastructure in project design.   

The MRP defines Green Infrastructure as: Infrastructure that uses vegetation, soils, and natural processes to manage water and create healthier urban environments. 

At the scale of a city or county, green infrastructure refers to the patchwork of natural areas that provides habitat, flood protection, cleaner air, and cleaner water. At the scale of a neighborhood or site, green infrastructure refers to stormwater management systems that mimic nature by soaking up and storing water. Examples of Green Infrastructure include:

  • Stormwater Planters
  • Stormwater Curb Extensions
  • Rain Gardens
  • Green Gutters
  • Tree Well Filters
  • Stormwater Trees
  • Trees in the Landscape
  • Infiltration Systems
  • Pervious Pavement
  • Green Roofs
  • Green walls
  • Rainwater Harvesting
  • Vegetated Swales

Green infrastructure design should achieve three primary stormwater management goals: water quality improvement, flow reduction, and volume reduction. These interrelated goals help foster a balanced development condition that manages stormwater in a way that is closer to pre-development conditions. 

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