Fiona Lawler

This research examines the long-term success of the 2005 Capistrano Fish Restoration Project in San Pedro Creek, Pacifica, CA. It analyzes how the stream channel has evolved over the past two decades, evaluates geomorphic changes affecting fish habitat, assesses whether the restoration structures continue functioning as intended, and determines whether natural log and pebble recruitment could support a process-based restoration. Initial cross-section data provide insights into these changes, showing that the stream bed has widened and a side channel has been formed.

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, stream channel erosion has led to steep slopes, making the fish ladder at the Capistrano Bridge nonfunctional, and creating a barrier for the upstream migrating endangered 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 by analyzing the stream channel dimension, geomorphic changes impacting fish habitat, whether the restoration structures are still functioning as intended, and whether natural log and pebble recruitment could support a process-based restoration. This project will evaluate whether the restoration project has met its long-term goals and if further improvements will be needed.