Upper Sand Creek Basin

Upper Sand Creek Basin Expansion Project

The Upper Sand Creek Basin Expansion Project was a $10 million flood protection and habitat restoration project constructed in Antioch, California. The purpose of the project was to attenuate flows from the Upper Sand Creek watershed, which will help provide flood protection for the communities downstream. Project components included expanding the basin to store 8 times more storm water than before, building an 1800-foot-long dam, ranging in height from 1 to 40 feet, restoring 3,500 linear feet of Sand Creek, including planting over 2500 willow trees, creating 10 acres of wetlands inside the basin, and installing an innovative trash capture device to help clean up the creek.

Nomad prepared a Biological Resources Assessment, Wetland Delineation, a protocol-level rare plant survey report, and a Planning Survey Report in compliance with the East Contra Costa County Habitat Conservation Plan/Natural Communities Conservation Plan (HCP/NCCP) for the project. Nomad’s technical reports were used in support of CEQA and regulatory permits including California Department of Fish and Wildlife’s Streambed Alteration Agreement, U.S. Army Corps of Engineers 404 permit, and Regional Water Quality Control Board 401 permit. Nomad’s GIS department prepared figures for the project that clearly demonstrated the location of biological resources and calculated project impacts.

The project was also permitted through the East Contra County Habitat Conservation Plan. Protected species that occurred on the project site included California red-legged frog, burrowing owl, California tiger salamander, and nesting birds. Nomad conducted preconstruction surveys and wildlife exclusion prior to the start of construction including burrowing owl passive relocation, nesting bird surveys, nest exclusion, fish relocation, and California red-legged frog surveys and relocation. Nomad conducted worker training and construction monitoring for the project to remain in compliance with the project permits. Construction of this project was completed in 2013. Nomad oversaw site restoration including the planting of 1,200 riparian trees and shrubs and seeding native grasses and forbs.

Nomad is currently 7 years into a 10-year contract to conduct annual monitoring of the restoration site as required by the project permits. Since 2014, Nomad has conducted restoration monitoring of the site, tracking multiple success criteria site-wide and producing detailed annual monitoring reports for submittal to regulatory agencies.


Location: City of Antioch, Contra Costa County
Client: Contra Costa County Public Works Department

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