BOARD AGENDA MEMORANDUM
SUBJECT:
Title
*Guadalupe River Project from Tasman Drive to Interstate 880 (District 3) (San Jose).
End
RECOMMENDATION:
Recommendation
*Add the Guadalupe River Project from Tasman Drive to Interstate 880 to the Fiscal Year 2020-2024 Capital Improvement Program (CIP) to evaluate possible alternatives to restore the design flow conveyance capacity of the Lower Guadalupe River.
Body
SUMMARY:
History of flood protection improvements
In 1983, improvements on the Lower Guadalupe River, from the Union Pacific Railroad (UPRR) in Alviso to Highway 101 were constructed to provide 100-year flood protection. In March 1992, the District signed a Local Cooperative Agreement (LCA) with the U.S. Army Corps of Engineers (USACE), whereby the District agreed to operate and manage the Lower Guadalupe River to provide a 100-year flood protection, when the USACE Downtown Guadalupe River Flood Protection was completed in 2004.
Based on the field data collected from the January and March 1995 storm events, a hydraulic analysis in 1995 showed that the Lower Guadalupe River did not have the planned conveyance capacity as required by the Downtown Guadalupe River Project. Both vegetation growth and sediment deposition were identified as the main causes of reduction in channel capacity.
In 2004, the District completed additional flood protection improvements along the Lower Guadalupe River from Alviso Marina to Interstate 880 at the same time as the USACE completed construction of the Downtown Guadalupe River Flood Protection Project. The 2004 improvements included: vegetation management and sediment removal; levee rehabilitation; levee raising; floodwalls; maintenance roads and ramps; and replacement of the State Route 237 east-bound bridge over Guadalupe River. Together, the Lower Guadalupe River and Downtown Guadalupe River Flood Protection Projects removed 3,440 parcels from the floodplain.
Staff worked with USACE staff to ensure that the USACE...
Click here for full text