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Best Available Maps

In October 2007, Governor Arnold Schwarzenegger signed into law Senate Bill 5 (SB 5), which requires the Department of Water Resources (DWR) to develop preliminary maps by July 1, 2008 for the 100- and 200-year floodplains located within the Sacramento-San Joaquin Valley watershed. SB 5 requires that these preliminary maps be provided as best available information on flood protection to cities and counties in the watershed for

  1. areas protected by State-Federal project levees, and
  2. areas outside the protection of project levees.

SB 5 also requires the Department to notify and inform these areas of available maps and other information that describe their respective flood hazards.

Pursuant to the legislation, DWR has prepared the preliminary 100- and 200-year maps for 32 counties and 91 cities located within the Sacramento-San Joaquin Valley watershed. These maps were developed based on the best information currently available. The Department has initiated several projects that will provide updated information about flood hazards in the Sacramento-San Joaquin Valley over the next two to four years. These floodplain maps are subject to change and may be updated periodically.

(Text of Legislation, History of Legislation, Legislation Status)

Please select the county you are interested in by clicking on the appropriate area below.

Disclaimer: These maps have no regulatory status for floodplain development and are for information only. They do not replace existing Federal Emergency Management Agency (FEMA) regulatory floodplain maps or Central Valley Flood Protection Board (CVFPB) regulatory floodway maps. For more information on the FEMA or CVFPB regulatory maps, please contact those agencies directly. The intent of the Best Available Maps is to promote sound community-based flood risk management and multi-hazard planning. The maps should also be used to identify potential flood risks that may warrant further study or analyses. The floodplains shown delineate areas with potential exposure to flooding for two different storm events: one with storm flows that have a 1% chance of being equaled or exceeded in any year (100-year) and one with storm flows that have a 0.5% chance of being equaled or exceeded in any year (200-year). These flows and resulting flooded area are based on the best available floodplain information and may not identify all areas subject to flooding.

For more information on

Siskiyou County Modoc County Lassen County Shasta County Tehama County Plumas County Sierra County Butte County Glenn County Lake County Colusa County Sutter County Yuba County Nevada County Placer County El Dorado County Napa County Yolo County Sacramento County Amador County Solano County Contra Costa County San Joaquin County Calaveras County Alpine County Stanislaus County Tuolumne County San Benito County Merced County Mariposa County Madrea County Fresno County

SB 5 defines the Sacramento–San Joaquin Valley as "any lands in the bed or along or near the banks of the Sacramento River or San Joaquin River, or any of their tributaries or connected therewith, or upon any land adjacent thereto, or within any of the overflow basins thereof, or upon any land susceptible to overflow therefrom. The Sacramento–San Joaquin Valley does not include lands lying within the Tulare Lake basin, including the Kings River."

For more information, please contact Ricardo Pineda at rpineda@water.ca.gov or by phone at (916) 574–1475.