Lake Cachuma Area-Capacity Survey

Background
The Santa Barbara County Water Agency (SBCWA) is seeking proposals from qualified consulting firms to conduct an Area-Capacity Study of Lake Cachuma. This study aims to develop updated elevation-area and elevation-capacity relationships, quantify sediment accumulation since 2021, improve accuracy of reservoir storage calculations, and support water supply planning and operational decision-making. The last survey was completed in 2021, and updated data is necessary due to potential changes in sediment deposition and operational conditions.

Work Details
The contract involves performing a combined aerial and bathymetric survey, including the following specific tasks:
- Conduct a bathymetric survey using multibeam or equivalent technology.
- Perform a topographic survey of exposed reservoir areas using methods such as LiDAR, UAV, or conventional techniques.
- Establish appropriate horizontal and vertical control for the surveys.
- Coordinate fieldwork with relevant agencies including the U.S. Bureau of Reclamation and local recreation area staff.
- Develop a Digital Elevation Model (DEM) of the reservoir basin by merging bathymetric and topographic datasets.
- Compute reservoir volume, surface area at varying elevations, and sediment accumulation since the last survey.

Deliverables include:
- Elevation-Capacity Table in Excel format covering elevations from approximately 601 ft to 760 ft (MSL), with both NGVD29 and NAVD88 datums.
- Composite topographic/bathymetric map in GIS and CAD formats with complete metadata documentation.
- A technical report detailing methodology, accuracy assessments, sediment analysis, comparison to previous results, limitations, and assumptions.

Period of Performance
Field work is expected to be completed by August 31, 2026, with a draft report due by September 30, 2026. Final deliverables are required no later than November 1, 2026.

Place of Performance
Lake Cachuma Recreation Area in Santa Barbara County, California.

Bidder Requirements
Proposals must describe survey methodologies under the supervision of a California Licensed Land Surveyor. Compliance with Lake Cachuma access requirements is mandatory; this includes vessel inspection protocols due to Aquatic Invasive Species prevention measures.