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Willdan Engineering has expertise in all aspects of drainage and flood control, ranging from local and regional drainage and flood control improvements to hydraulic and sediment transport analyses of major rivers. Willdan Engineering has worked with numerous cities to ensure compliance with the National Pollutant Discharge Elimination System (NPDES) municipal storm drain requirements.

  • Master Plans
  • GIS services
  • Hydrology Reports
  • Feasibility Studies
  • Federal Insurance Studies (LOMR, CLOMR)
  • Storm Water and Drainage Design
  • Channel Improvements
  • Pollution Discharge Requirements/Permit Processing
  • Hydraulic Models
  • Scour and Sediment Transport Analysis
  • Debris Dam and Side Weir Design
  • Retention and Detention Basin

Representative Projects

City of Elk Grove, Rain Garden–Sacramento County, California

Elk Grove rain garden

American Society of Civil Engineers “Sustainability Project of the Year”

The City of Elk Grove transformed a blighted one-acre site into an educational and recreational experience that mimics a natural approach to retaining and cleansing urban stormwater runoff to protect the environment and promote future sustainable development practices. One of the first large-scale rain gardens in California and the recipient of nine prestigious awards, the project demonstrates the connection between a small urban space and innovative stormwater management practices through simple and cost-effective low impact development techniques, documented in a video by ThankYouOcean.net.

Willdan staff provided project management, engineering, sustainable development design, construction management, stormwater management design, public involvement  and public outreach support, and client relations support.

U.S. Army Corps of Engineers, L.A. River — Los Angeles County, California

LA River

APWA National Project of the Year, Disaster or Emergency Construction/Repair

This award-winning, five-year project increases the floodwater capacities of both the Rio Hondo Channel and the Los Angeles River to facilitate a 133-year storm, saving residents in 14 communities millions of dollars in flood insurance. The $216-million project raised the height of 21 miles of existing levees from 3 to 6 feet and modified 24 bridges.

Willdan was responsible for more than $130 million in preliminary and final design of channel improvements; railroad, pedestrian and utility bridges; parapet walls; access roads; and landscaping.