Retrofitting Impervious Urban Infrastructure with Permeable Pavers - Lessons Learned and Results
This presentation will detail the effectiveness of retrofitting impervious Urban Infrastructure with permeable pavers. It will illustrate the lessons learned in construction and design, and reveal monitoring results.
The City of Santa Barbara has installed permeable pavers to replace impervious surfaces in several sites throughout the City since 2011, and has plans to complete more. These are designed to demonstrate how project sites can be retrofitted to allow for existing uses, and comply with the City’s Stormwater Management Program requirements of capturing and treating stormwater. Permeable pavers were chosen for their durability, passive treatment, and aesthetics. A cost analysis was conducted to compare permeable pavers to asphalt and concrete over the life of the projects. Pollutant load reduction is measured by collecting pre-project runoff and analyzing it for a wide range of pollutants. Monitoring ports are built into each of the project sites. These enable the collection of data showing the rise of water in the basins during rainfall events and the fall of water as it infiltrates into the subgrade soil. This can be used monitor the long-term performance of the project in collecting and infiltrating stormwater. During design and construction of the projects, important lessons were learned. Design and construction will be presented in several basic principles. Maintenance will also be discussed.
Tools, Ideas, and Concepts
Six basic design and construction details include: a level sub-grade with adequate compaction, edge restraints that detain water under the pavers, the use of open graded crushed aggregate as base, base compacted in 4-6 inch lifts, sealed utilities within the basin, long lasting permeability in the pavers, pre-project monitoring, and installation of monitoring ports, and methods to address stormwater run-on.
Engaging the Audience:
A couple of short anecdotal stories will be shared to illustrate some of the lessons learned. Also, the talk not be too long, allowing for plenty of time for questions and discussion afterwards.
Addressing the Conference Theme:
Stormwater – Are we making a difference? This presentation will detail the difference permeable pavers can make on urban hydrology and storm water quality, illustrate tools and methods to maximize this difference, and track the changes.