print Font Size: small font medium font large font

E3: Flood Risk Reduction Studies

This project develops engineering studies to understand the actual flood risks in high priority flood-prone areas; and develops options for managing  the flood  risks.

Studies focus on the following reaches: 

  • Alamitos Creek, upstream of Almaden Lake in San José
  • Rock Springs neighborhood along Coyote Creek in San José
  • Calera Creek, near Milpitas High School to Interstate 680 in Milpitas
  • Tributaries to Lower Silver Creek (Ruby, Norwood, Quimby and Fowler creeks) in San José

 The study includes hydrology, hydraulics, geotechnical, and remapping work of the floodplain areas. If appropriate, updated maps will be submitted to Federal Emergency Management Agency (FEMA) to provide a more accurate reflection of the floodplain.


  • Provides more accurate mapping of areas at risk of flooding
  • May add or remove parcels from the FEMA regulatory floodplain, based on updated mapping standards
  • Information can be integrated into flood warning program to provide advance, real-time warnings of impending flood events 
  • Provides technical basis for developing future flood protection plans, and for potential funding partnerships

Project Status

(As of September 2017)

  1. A 2-dimensional, unsteady hydraulicmodel for mid-Coyote Creek was completed in early 2016; it has been extended upsteam to include the Rock Spring neighborhood and is in the process of being calbrated to match high water marks from the February 2017 storm event, expected in early FY 2018.
  2. For Alamitos Creek, a geotechnical investigation for the levees/floodwall and a 2-dimensional model were both completed in the third quarter of 2016. Based on this information, preliminary floodplain maps were developed and presented to the City of San José in June 2017. The District will finalize the maps and will continue to work with the city to decide how the information should be used.

Key Performance Indicators

  1. Complete engineering studies on 7 creek reaches to address 1% flood risk. 
  2. Update floodplain maps on a minimum of 2 creek reaches in accordance with new FEMA standards. 



Priority E-200

FY17 Annual Report Status 

StatusOn Target
Project StartFY 2014
Project FinishFY 2022
Safe Clean Water
Program funding

$8.7 M**

(2015 Dollars)

**More financial information: 5-Year Implementation Plan, pages: 19-27

For more information:


Completed Work

   Preliminary 100 Year Flooplain Maps (PDF)