ASCE OC EWRI: The City of Santa Ana Flood Reduction & Stormwater Infiltration Project

In April 2026, members attended an informative presentation on the City of Santa Ana Downtown Flood Reduction and Stormwater Infiltration Project, an award-winning infrastructure project that demonstrates how innovative stormwater management can provide flood protection, improve water quality, and enhance community amenities.

The presentation was delivered by Craig Foster, EIT, CPSWQ, QSD/P, NPDES Manager for the City of Santa Ana. During his more than nine years with the City's Public Works Agency, Craig has focused on developing and expanding the City's stormwater capture program. He holds a Bachelor's Degree in Earth Sciences from UC Santa Cruz and a Master's Degree in Environmental Engineering from UC Irvine.

Presenter Craig Foster at the project site.

Craig began by discussing the importance of stormwater capture and the numerous benefits these types of projects provide. In addition to helping municipalities meet Municipal NPDES permit requirements and reducing pollutant discharges to receiving waters, stormwater capture projects can reduce flooding, increase local water supplies, improve neighborhood aesthetics, create new recreational opportunities and green spaces, and help mitigate urban heat island effects. He also highlighted regional planning efforts, including The OC Plan, the Integrated Regional Water Management Plan for North and Central Orange County, which guides the development of water resource projects throughout the region.

The presentation then focused on the Downtown Flood Reduction and Stormwater Infiltration Project, which was completed in June 2025 and received a 2025 APWA BEST Award. The project utilizes a two-pronged approach to reducing flooding in Downtown Santa Ana. Approximately 1,000 linear feet of existing storm drain infrastructure was upgraded to increase conveyance capacity. In addition, a subsurface stormwater infiltration system was constructed beneath a City-owned parking lot, removing stormwater flows from the drainage system and directing them into the ground for recharge.

View of the project's subsurface stormwater infiltration system.

The project is designed to capture and infiltrate runoff from a 19.3-acre drainage area, providing approximately 8.8 acre-feet (2.9 million gallons) of stormwater capture annually. The improvements also included reconstruction of the City-owned parking lot, installation of drought-tolerant landscaping, and interpretive signage that educates the public about the project's environmental benefits.

Attendees learned about the factors that contributed to the project's success, including the project’s necessity due to historical chronic flooding, the availability of City-owned property, favorable soil conditions for infiltration, and strong community support. The City also successfully secured $5.05 million in Proposition 68 Urban Flood Protection Grant funding from the California Natural Resources Agency to help bring the project to fruition.

Attendees listening to the presenter describe the project.

Craig also shared several key design considerations and lessons learned. Extensive percolation testing was performed to identify soil layers with the highest infiltration rates, ultimately leading the design team to utilize drywells that could access deeper sand and gravel layers. Utility investigations and potholing were conducted throughout design to minimize construction conflicts in the utility-dense downtown environment. To protect groundwater resources, the project incorporated a spill isolation valve and upstream signage, along with an advanced cartridge media filtration system to provide pretreatment before stormwater enters the infiltration facilities.

The event provided attendees with valuable insights into the planning, funding, design, and construction of multi-benefit stormwater infrastructure. Craig's presentation highlighted how innovative engineering solutions can address flood risk, improve water quality, support groundwater recharge, and create lasting benefits for local communities.

ASCE OC EWRI Chair Ben Smith honoring Presenter Craig Foster with a plaque of appreciation.

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About the Author:

Jenny Robinet is a Project Manager at Pacific Advanced Civil Engineering (PACE) in Orange County, CA. She loves working on various stormwater projects and being involved in the civil engineering industry, especially ASCE where she currently serves as Orange County Branch President-Elect. Jenny can be contacted at jrobinet@pacewater.com or https://www.linkedin.com/in/jenny-robinet.