Pasadena Water & Power

Arroyo Seco Canyon Project

 Arroyo Rendering Cropped 

At a Glance

The Arroyo Seco is a tributary to the Los Angeles River that originates in the San Gabriel Mountains and flows south through the communities of Pasadena, South Pasadena, and Northeast Los Angeles. The Arroyo Seco Canyon Project (ASCP) is an endeavor to take a multi-benefit approach to improve water resources and natural habitat while enhancing the recreational experience for visitors in the area between Hahamongna Watershed Park in Pasadena and the Angeles National Forest.

ASCP is a partnership between the Arroyo Seco Foundation (ASF) and Pasadena Water and Power. Some project elements include:

  • Rehabilitation of the Arroyo Seco Intake - The upgraded facility will better manage sediments and improve the opportunity to capture stream water for replenishing the City’s groundwater, which is later pumped for potable water. 
  • Installation of a public restroom and parking area - A restroom facility will be built next to a new public parking area for recreational users of the Arroyo Seco.
  • Removal of unused water facilities - The Headworks facility, which was in use by PWP for many decades, will no longer be necessary with the new improvements at the Arroyo Seco Intake and at other water facilities. The Headworks will be removed allowing for naturalization of the stream and improve aquatic connectivity.
  • Habitat restoration – After the Headworks facility is removed, the project area will be restored with native vegetation with the goal to reestablish a riparian habitat. Invasive species will also be removed through clearing of non-native plants.
  • Improving passive recreational opportunities - Installation of interpretive signs, picnic tables, a drinking fountain, and a horse trough will enhance recreational use. 


The project is supplemented by a $3.27 million grant provided by the State of California Department of Water Resources under Proposition 84. ASF provided the initial conceptual design and secured the grant funding through the California Integrated Regional Water Management Program.


A Conditional Use Permit (CUP) application for this project has been approved.  The final Initial Study/ Mitigated Negative Declaration (IS/MND) was approved following a Public Hearing on June 1, 2015. The document is now available for review:

Click here to view IS/MND Document   

Appendix A - Air Quality Modeling Data 

Appendix B - Biological Technical Report 

Appendix C - Cultural Resources Assessment 

Appendix D - Geotechnical Report 

Appendix E - Noise Monitoring Data    


PWP Contact

Elisa Ventura, Principal Engineer
(626) 744-4465




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