Evaluating the Long-term Success of a Stream Restoration Project in San Pedro Creek, Pacifica, CA
Fiona Lawler
School of the Environment
Faculty Supervisor: Jerry Davis
Urbanization increases impervious surfaces which leads to an increase in runoff, effectively creating a flashier stream hydrograph. The increased stream flow leads to channel enlargement where net lateral channel erosion and channel incision enlarge the stream channel. In San Pedro Creek Pacifica, CA, deep incision below the Capistrano Bridge culvert made the fish ladder installed there nonfunctional, and creating a barrier for federally threatened steelhead trout. The Capistrano Fish Restoration Project completed two decades ago restored the stream reach by gradually increasing the slope with log step-pools and installing a new fish ladder to improve stream health and habitat. This research examines the long-term effectiveness of the stream restoration project and results show that it is still a success after 20 years with the longitudinal profile changing dynamically. Most restoration structures are still functioning as intended, although natural log recruitment will be limited due to the small diameter of the riparian trees and pebble sizes in transport are unlikely replacements.