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Department of Public Works

  • The Natural Environment

    The Arroyo Seco contains a dynamic stream that begins high in the San Gabriel Mountains and flows through the communities of La Canada Flintridge, Altadena, Pasadena, South Pasadena and Los Angeles, where it meets the waters of the Los Angeles River and continues on to the Pacific Ocean. In making this journey, the stream cuts a narrow, deep canyon through these communities and gave birth to much of the culture, history and unique identity within the region of this riparian corridor.

  • The Arroyo Seco Watershed

    The Arroyo Seco Watershed encompasses a total area of approximately 47 square miles. The towering San Gabriel Mountains define the upper watershed boundary shedding water into the Arroyo Seco, a 22 mile long stream. The Arroyo Seco passes through a landscape of rugged mountain terrain, narrow canyon land, and fertile floodplain before it joins with the waters of the Los Angeles River eventually draining into the Pacific Ocean.


  • Restoration Projects in the Arroyo

    The Arroyo Seco landscape provides the habitat to sustain the rich biodiversity found within this breathtaking canyon. However, over the last few centuries, human impacts on the Arroyo have taken their toll compromising the integrity of this vital landscape. Efforts to restore the habitat and mitigate the human impacts have been underway for the past few decades. Following is a brief list of a few recent restoration projects:

    • Stream Diversion in the Lower Arroyo
    • Central Arroyo Stream Restoration
      • Concrete Removal beneath I-210
      • Reintroduction of Arroyo Chub to Central Arroyo
      • Parking Lot I Improvements
      • John Crowley Trail Restoration
    • Archery Range Planting Restoration
    • Memorial Grove Planting Restoration

    There is a planning process for Arroyo Seco restoration.

    Learn more >> 

  • Ecology of the Arroyo Seco

    Steep slopes, the presence of water, periodic flooding, and natural geography of the canyon contribute to the rich diversity of plant and animal life found in the Arroyo Seco.

  • Sights and Sounds from the Arroyo

    A Gallery of Images & Media

    Images and media including a film prepared for the City of Pasadena featuring the Arroyo Seco.

    Learn more >>

  • Learn more about the Natural Environment in the Arroyo

    Recreation, restoration, and conservation events are hosted year round in the Arroyo by organizations and groups. For more information on groups regularly hosting events in the Arroyo , please visit their websites:

    Arroyo Seco Foundation

    Sierra Club, Angeles Chapter Pasadena Group

    Pasadena Audubon Society

Water Usage Gauge