The Santa Clara Valley Water District (Valley Water) is developing Stream Maintenance Guidelines for 30 creeks throughout Santa Clara County. The guidelines inform and facilitate Valley Water’s maintenance activities and also satisfy regulatory requirements to demonstrate the need for maintenance.
Valley Water maintains its creek facilities to convey storm flows draining from the upper watershed and from stormwater outfalls. When properly maintained, the channel facilities can convey flows at either their designed capacity, or at historic levels for non-engineered channels that have been modified or at unmodified channels. The design flow capacity establishes an expected level of service (LOS) for channels. Stream maintenance guidelines establish quantifiable objectives that define corrective and routine maintenance activities necessary to provide the established LOS at the channels while minimizing environmental impacts.
Since 2014, Horizon has worked closely with prime contractor ESA, to analyze and evaluate nearly 200 miles of creek channels and develop maintenance guidelines for up to 30 channels, including Calabazas, Stevens, Los Gatos, Guadalupe, Penitencia, Coyote, San Tomas Aquino, Matadero,and Saratoga creeks.
Developing the Maintenance Guidelines has involved reviewing existing as-built channel design and maintenance histories; conducting field surveys and creek assessments; identifying reach-specific right-of-way constraints; conducting hydraulic analysis; reviewing reach-specific land uses; assessing biological habitats; and recommending maintenance activites and locations. Horizon and team partner ESA coordinated closely with Valley Water staff to understand their needs in this project. Horizon integrated the collected stream channel information into a cohesive and specific stream maintenance guideline document for each channel system.