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Carriage Crest Park Stormwater Capture Project: Innovating for a Cleaner Machado Lake



The Challenge

In Carson, California, the Dominguez Channel Watershed Management Group identified Carriage Crest Park as a high-priority site for a regional stormwater capture project. With two large storm drains serving a drainage area exceeding 1,100 acres, the site presented a unique opportunity to address water quality issues in Machado Lake, the ultimate recipient of this runoff via Wilmington Drain. The primary challenges were eliminating dry-weather runoff into Machado Lake and reducing wet-weather pollutant loading.


Our Approach

Craftwater Engineering, as a subconsultant, supported the City of Carson with a comprehensive solution. 


Here's how we orchestrated our approach:


  1. Innovative Design Development: Our team led the creation of the preliminary engineering design report, incorporating analysis and innovative water use and treatment scenarios.

  2. High-Performance Water Quality Management: We designed a system capable of treating the 85th percentile runoff volume for both the City of Carson (15 acre-feet) and the County Unincorporated Area (12 acre-feet).

  3. Integrated Stormwater Infrastructure: We developed a multi-component system including:

    • A Storm Drain Diversion System with two drop inlet structures from BI 1201 – Line A

    • A Subsurface Storage and Diversion Facility, featuring a 4.4 million-gallon (13.4 acre-feet) underground storage reservoir

    • A Discharge System to the Sanitary Sewer, allowing a maximum nightly discharge of 34 cfs to the existing 60" sanitary sewer in Figueroa Street for further treatment

  4. Detailed Technical Execution: Our team spearheaded the development of design drawings, cost estimates, and specifications for both the pre-cast structures package and the construction of the regional stormwater BMP facility.

  5. Ongoing Support: Craftwater Engineers continue to provide support during the construction phase, ensuring the project's successful implementation.

  6. Collaborative Funding: The $18.2 million project showcases effective collaboration, with $13 million funded through a cooperative agreement between the City of Carson and the State of California Department of Transportation, and the remaining $5.2 million from Los Angeles County Unincorporated Area.


Key Takeaways

  • Innovative Stormwater Management: Designing a system that addresses both dry-weather runoff and wet-weather pollutant loading

  • Large-Scale Impact: Managing stormwater from over 1,100 acres to improve the water quality of an entire lake

  • Integrated Infrastructure: Successfully incorporating major stormwater management facilities within an existing park

  • Collaborative Funding: Leveraging partnerships between city, state, and county entities to finance a significant environmental project

  • Continued Expertise: Providing ongoing support from design through construction, ensuring project success

  • Scalable Solutions: Demonstrating the potential for similar large-scale stormwater capture projects in urban areas


This project demonstrates Craftwater's ability to tackle complex water quality challenges through innovative design, collaborative approaches, and long-term commitment to project success.

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