In 2007, the Cachuma Operation and Maintenance Board selected our team to prepare a Fish Passage Assessment and Enhancement Plan for Quiota Creek near Santa Ynez, California. We performed site reconnaissance and field data collection to evaluate and classify nine fish passage impediments along South Refugio Road. All crossings are located within the limits of endangered Southern California Evolutionary Significant Unit Steelhead.

Based on synthesis of the collected data, we prepared a watershed-based fish passage enhancement plan that entailed alternative formulation and evaluation with a multi-variable weighted selection factor approach; conceptual design of culverts, single-span bridges, and fishways; flood frequency analysis; and hydraulic analysis. Fish passage evaluations were conducted per California Department of Fish and Game Chapter IX protocol. Culvert design was performed using both hydraulic and stream simulation methods for box, round, and arched-type concrete and metal culverts. Conceptual designs for each impediment remediation project included habitat improvement components such as step pools, rock riffles, profile control features, engineered wood structures, and native riparian plantings. Results from this document were used as the framework for leveraging grant money through multiple grant programs available to similar projects in Southern California.

Subsequent to our completion of the Quiota Creek Watershed Fish Passage Enhancement Plan, we were tasked to complete detailed design drawings, technical specifications, and engineer’s opinion of probable construction costs for 10 consecutive water crossing projects prioritized in the enhancement plan. Each project included the replacement of concrete slab low-flow stream crossings with prefabricated concrete arch bridge systems. Design tasks included HEC-RAS modeling, instream channel design, scour countermeasures, rock profile control structures, fish habitat features, and road design. All designs were closely coordinated with design reviewers from State and Federal fisheries agencies and followed applicable Stream Simulation and Aquatic Organism Passage design guidelines. Throughout design, the design team provided grant writing support and assisted COMB in leveraging over $5 million in construction funds.

To date, we have provided construction oversight for Crossing 0A, 1, 2, 3, 4, 5, 6, 7, 8 and 9. Tasks performed by our team during construction included: direct collaboration with contractors; on-site construction observation; field-fit construction oversight for habitat elements and streambed features; review of RFIs and shop drawing submittals; review of payment requests; and final project walkthrough. We continue to collect data and develop annual passage evaluation reports for each of the constructed projects.