Arroyo Seco Watershed Assessment

1. Upper Arroyo Seco Restoration

Purpose:To improve riparian and riverine habitat on the Arroyo Seco through stream stabilization, aquatic habitat connectivity, and riparian habitat restoration through control of invasive species. Anthropogenic structures (e.g. road crossings, water supply diversions, and flood control dams) have adversely affected fish passage, and aquatic and riparian habitats.
Location:begins at the JPL bridge and extends upstream to the headwaters in the San Gabriel Mountains

The Upper Arroyo Seco Channel Restoration project is an integrated recreation, water resource, and habitat enhancement project that extends from the JPL bridge upstream to the headwaters in the San Gabriel Mountains that will improve water supply, recreation, water quality, and ecosystem health. The Upper Arroyo Seco Channel Restoration project is a culmination of years of grassroots planning efforts and analysis focusing on southern California ecosystems. Above the JPL bridge, the primary habitat disruptors are impediments to fish passage, forage, rearing and spawning including anthropogenic structures such as road crossings and water supply diversion and flood control dams. These impediments have adversely impacted aquatic and riparian habitats that are becoming increasingly endangered. In addition to creating fish passage barriers, anthropogenic features also can result in localized erosion that has an impact on stream channel stability and sediment deposition that adversely impacts streambed and riparian habitat. Non-anthropogenic causes of erosion, such as wildfires, also have an impact on channel stability, habitats and downstream flooding and sedimentation. An awareness needs to be developed of wildfire impacts on Arroyo Seco morphology and habitat. Although, such impacts from natural causes may be best left to evolve naturally.

Key Project Components:


Arroyo Seco Watershed Assessment

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