Flood Control Zone 6
Zone 6 at a Glance
Communities served: southern Alameda County, includes the Irvington, Mission San Jose, and Warm Springs regions of Fremont
Area in acres: 27,400
Total miles of natural creek: 43
Total miles of earth channel: 20
Total miles of concrete channel: 6
Total miles of underground pipe: 14
Creeks: Morrison Creek, Mission Creek Arroyo de le Laguna, Arroyo Aqua Caliente, Canada Del Aliso, Arroyo Aqua Fria, Toroges Cress, and Scott Creek
Reservoirs: Lake Elizabeth
Zone 6 Hydrology
Waterways flow from the foothills of Mission Peak, Mt. Alison, and Monument Peak above Fremont down toward the city. Within the City of Fremont, stormwater reaches San Francisco Bay by flowing through a series of pipelines and earthen and concrete channels to either Mowry Slough or Coyote Creek, which form the border between Alameda and Santa Clara Counties.
The flatter portion of Zone 6 is an alluvial plain made up of sediment deposited by water flowing to the Bay. Silt can clog flood control channels and restrict stormwater flow, so District Maintenance and Operations crews remove a great deal of silt from this zone’s waterways.
Zone 6 Major Projects
Line I Flood Control
Growing Fremont neighborhoods require the District to increase regional flood control capacities. The Line I capacity improvement project, running from Line E to the Southern Pacific Railroad, was designed for that purpose.
Construction of the original design was halted due to worldwide price increases for steel and concrete. District engineers then re-evaluated the design and decided to raise portions of an existing roadway rather than replace sections of concrete floodwall to achieve the same level of flood protection as the original plan. As a result, the project budget was cut nearly in half from $1.2 million to $614,000.
Construction on the Line I improvements will begin in fiscal year 2007 and conclude in fiscal year 2008.
Lake Elizabeth
Lake Elizabeth is a recreational reservoir with boating and fishing located on District property, and maintained by the City of Fremont. The lake, which has undergone major silt removal, also provides flood protection by retaining stormwater flow from upstream hills, then releasing water into downstream flood control channels at a measured rate.
New and Ongoing Projects in Zone 6
- Line I Capacity Improvement between Montrose and Union Pacific Railroad (UPRR)
- Line D (near Briar Place) Storm Damage Repair
For more information about the history of projects undertaken in Zone 6, please view the District’s Annual Reports.