Arroyo Hondo Steelhead Passage Design, Permitting, and Construction Oversight

Santa Barbara County, California

Client: Land Trust for Santa Barbara County

Arroyo Hondo Creek has the second highest upstream habitat score for endangered steelhead in the south coast area of Santa Barbara.  The Land Trust for Santa Barbara County retained Questa to design a culvert retrofit to facilitate fish movement through an approximately 300-foot long by 10-foot wide concrete culvert under Highway 101 near the mouth of Arroyo Hondo Creek.  Five inter-related objectives were identified to achieve project success:

(1) Modify the culvert to improve conditions for successful fish passage.
(2) Ensure that the structural integrity of the tunnel and nearby infrastructure was not compromised.
(3) Ensure that the tunnel continued to have sufficient hydraulic capacity for normal and high creek flows without increasing the risk of flood damage.
(4) Maintain pedestrian access from the main part of the Preserve to the beach.
(5) Restore and improve ecological/biological functions immediately upstream and downstream of the tunnel.

To accomplish these objectives, Questa evaluated and developed potentially feasible design alternatives in a conceptual design phase. Based on input from the Land Trust, and regulatory and funding agencies, Questa prepared final design plans and costs estimates for the preferred alternative. Permits were obtained from numerous entities, including USCOE, CDFG, USFWS, NOAA, Calif. Coastal Commission, UPRR, and Caltrans. Questa also prepared a Draft Initial Study, a Habitat Mitigation & Monitoring Plan, and specialized endangered species surveys, in addition to overseeing construction.