Central Arroyo Seco Stream Restoration near Downtown Los Angeles

The purpose of the Central Arroyo Seco stream restoration in Pasadena, California is to create habitat conditions suitable to sustaining the arroyo chub, a native fish of the Arroyo Seco. Current instream conditions within the natural channel reaches are characterized by adequate over bank vegetative cover but an absence of pools needed for refuge and resting areas and juvenile rearing and relatively few trailing vegetation or other firm substrate like rocks or logs in slower flowing runs needed for spawning. The natural channel reaches are also subject to flash flood events due to the highly impervious upstream-urbanized watershed, operational releases from the Devils Gate Dam and the hydraulic efficiency of the concrete-lined channel reach. Proposed improvements consist of backwater pools, riffle/weirs located at the upstream and/or downstream ends of the backwater pools, and a series of wing deflectors and snags. Local materials including boulders, fallen trees and logs, and root wads will be utilized, to the extent feasible, in the construction of stream channel enhancements.