Valley Water is dedicated to keeping residents and businesses safe through its flood protection programs. The Guadalupe River - Tasman Drive to Interstate 880 Project will restore the river’s flood protection level to its design capacity of a 100-year flood and provide natural flood protection for residents and businesses. The project limits are from Tasman Drive in Santa Clara to Interstate 880 near Airport Parkway in San Jose.
As of fall 2019, Valley Water is completing the problem definition phase and is identifying conceptual design alternatives. Staff will perform an analysis to evaluate the alternatives, and will ultimately select a staff-recommended alternative to present to the Board of Directors. Valley Water will hold several public meetings during this process to provide updates to residents and to gather input from the community on project alternatives. The alternative recommended by staff and approved by the Board will move to the design phase.
A meeting was held Sept. 23 for the community to learn about the project and provide input on the current project alternatives.
For more information on the project, please contact:
Updated September 2019
When completed, the Guadalupe River Tasman Drive to Interstate 880 Flood Protection Project project will:
- Provide natural flood protection for residents, businesses, and visitors.
- Protect parcels from flooding by applying an integrated watershed management approach that balances environmental quality and protection from flooding.
- Preserve flood conveyance capacity and structural integrity of stream banks, while minimizing impacts on the environment and protecting habitat values.
The Lower Guadalupe River is the portion of the Guadalupe River between Interstate 880 and the San Francisco Bay. It has been the subject of several Valley Water flood protection projects over the years, the latest of which was the Lower Guadalupe River Project (LGRP) completed in 2004. This project provided 100-year flood protection for Interstate 880 to the Union Pacific Railroad bridge in Alviso, where the river enters the San Francisco Bay. The Guadalupe River has a long history of flooding, with the earliest recorded event occurring in the winter of 1852-1853.
The LGRP was constructed in conjunction with the Downtown Guadalupe River Project (DGRP), in which Valley Water partnered with the U.S. Army Corps of Engineers (USACE) to provide 100-year flood protection from the portion of the river between Interstate 880 and Interstate 280. As a condition of construction, the LGRP committed to USACE to provide enough capacity to carry the 100-year design flows from the Downtown Project, 17,000 cubic feet per second (cfs), as well as another 1,350 cfs from interior drainage inflow. The largest storm since the completion of both projects was February 2017, with a recorded peak of 6,340 cfs. A cubic foot of water contains nearly 7.5 gallons.
During high flow events, Valley Water staff routinely observes and records high water marks in the river and compares them to the expected water surface elevation based on the original design. In the Lower Guadalupe River, high water marks were measured during high flows in 2014, 2017, and 2019. It was determined that the Guadalupe River does not have sufficient capacity to carry the 100-year flows it was originally designed for. The stretch of creek without sufficient capacity is between Tasman Drive and Interstate 880. Therefore, the Board of Directors directed staff to expeditiously develop plans to restore the River's level of flood protection back to what it was designed to be, flood protection from a 100-year flow event.