Transforming Urban Water Initiative

From Gray to Green Shorelines

palo alto hl pics

Palo Alto Horizontal Levee Pilot Project

The Palo Alto Horizontal Levee Pilot (PAHLP) project is a novel and innovative initiative that links nature-based solutions to achieve habitat improvement, public access, flood protection and water quality improvement.

The San Francisco Bay has over two centuries of habitat loss and ecological degradation due to human activity. It is well established that the impact of these activities has modified important natural processes including freshwater flows, tidal exchanges, and the abundance of native species in some areas. These losses have led to fragmentation of habitats with reduced wildlife populations and systems that lack resilience to changing conditions. Meanwhile, the importance of restoration projects that achieve multiple objectives while repairing these natural processes is also well demonstrated. Visit the City of Palo Alto project website.


US Environmental Protection Agency
CA State Coastal Conservancy
City of Palo Alto
San Francisco Estuary Partnership
Environmental Science Associates

Overall Project Objective

The PAHLP project will engage communities and technical experts to design and permit a multi-benefit horizontal levee adjacent to the RWQCP. The project will restore critical habitat, support watershed adaptation to climate change, and improve water quality.

This project is a part of the Transforming Urban Water Initiative.

Project Goals

  • Restore rare and historic transitional habitat along the Bay’s shoreline for special status species.
  • Adapt to sea level rise by providing a vegetated slope that will support freshwater plants to build organic soils to keep pace with and allow wetland habitat to migrate up slope with rising water levels.
  • Provide polishing treatment of tertiary-treated wastewater.
  • Engage diverse populations of residents and interested stakeholders in sea level rise adaptation, habitat restoration, and shoreline planning activities.

Project Timeline

Project Resources

Watch the project webinar from November 16, 2021, “Sharing Space: Balancing Public Access and Habitat Enhancement at the Palo Alto Horizontal Levee Pilot Project”.