City of San Marcos Creek District Infrastructure Project

San Marcos, Calif.

Award of Merit

Submitted by: SEMA Construction Inc.

Owner/Lead Design Firm: California Dept. of Transportation

General Contractor: SEMA Construction Inc.


To improve accessibility and minimize flood risk in San Marcos Creek’s alluvial plain as well as preserve creek habitat and improve the ability to traverse the area, this $72.5-million project included construction of two new bridges at Via Vera Cruz and Bent Avenue, along with sidewalks and bike lanes. Crews also preserved and enhanced 1.5 miles of creek habitat and built a new neighborhood park and surrounding trail, completing work on schedule in March 2024.

The project focused heavily on utilities and included the installation of more than a mile of various size storm drains, a box culvert, an 1,800 linear ft sewer main, more than 4,500 linear ft of new water lines and a mile-long joint trench system.

Since the project is situated on a 100-year floodplain, construction activities were scheduled to coincide with the dry seasons as much as possible to reduce the risk of flooding and potential work stoppage.

Both the Via Vera Cruz and Bent Avenue bridges feature pile foundations to mitigate risks from seasonal floodwaters. But to complete this work, the team had to build creek diversions and earthen dams so the onsite team could work in mostly dry conditions.

An earthen levee will serve as an essential protective measure for the residents and roadways south of the project area, safeguarding them from potential future floods. Stretching 2,600 linear ft, the levee required excavation and embankment of about 46,000 cu yd of select fill.