Main Canal Modernization Studies

Main Canal

Purpose

The Canal Modernization Project is a multiyear effort that continues the Contra Costa Water District's history of improving its existing water infrastructure. The aim of the project is to study alternative facility configurations that could provide a modern conveyance system to meet long-term needs for safe, reliable and cost-effective conveyance.

Background

The Contra Costa Canal is a 48-mile aqueduct constructed in the 1930s and 40s to meet agricultural and industrial needs of the time. Throughout its 80-plus years, the area surrounding the canal has become urbanized and the canal now conveys water for municipal, commercial and industrial needs.

The Contra Costa Canal has two distinguishable segments:

  • Main Canal: The Main Canal is a 26-mile stretch from the District's Rock Slough intake to Clyde. This section of the canal delivers 99% of the District's untreated water. 
  • Loop Canal: The Loop Canal is a smaller, 22-mile section that carries water through Concord, Walnut Creek and Pleasant Hill before ending in Martinez. The Loop Canal provides redundancy to the District's Shortcut Pipeline and serves about 200 small water users for most of the year.

These studies are focused on evaluating options to modernize the Main Canal.

Challenges of an Open Water Canal

The Main Canal faces challenges and risks to continue providing safe, high-quality water that are exacerbated by the current demands and urbanization. These challenges and risks include:

  • Life safety: The canal presents a hazard to those who cross the fence lines.
  • Water quality: The open canal is vulnerable to water quality degradation, including algae that grows naturally within the canal, and contaminants from storm water runoff and spills.
  • Water supply: Earthquakes and landslides pose a risk to both the canal itself and the ability of the District to supply raw water to customers and its own treatment plants. Also, water is lost through evaporation and seepage through cracks in the aging concrete.
  • Increasing maintenance costs: Costs to preserve the existing water conveyance system are forecasted to increase as the canal system ages.

Modernizing the Main Canal  

The District is conducting a two-year study for advance planning and technical analysis for canal modernization. During this time, the District will:

  • Determine alternative facility configurations that are hydraulically feasible and meet operating conditions
  • Evaluate construction sequencing and approaches to maintain water supply and service
  • Review storm water management impacts and identify concepts for mitigation
  • Begin discussions with stakeholder agencies
  • Complete cost estimating and economic analyses

The District is studying options to modernize the Main Canal (shown below in blue and green). Further evaluation of the Loop Canal (shown below in red and pink) will be performed in the future.

canalmodernmap