This shapefile (polygon feature) contains the boundary of the July 1, 2022 100-Year Storm Flood Risk Zone, one of the layers of the July 1, 2022 100-Year Storm Flood Risk Map. Areas within this boundary are highly likely to experience “deep and contiguous” flooding during a 100-year storm. A 100-year storm is a storm that has a 1% chance of occurring in a given year. “Deep and contiguous flooding” means flooding at least 6-inches deep spanning an area at least the size of an average City block. The 100-Year Storm Flood Risk Zone does not provide the exact depth of flooding at a given location. It also does not show areas in the City that may experience shallower and/or more localized flooding in a 100-year storm. Finally, the 100-Year Storm Flood Risk Zone shows flood risk from storm runoff only. It does not consider flood risk in San Francisco from other causes such as shoreline overtopping and overland inundation from the San Francisco Bay or Pacific Ocean.

In addition to the 100-Year Storm Flood Risk Zone, the 100-Year Storm Flood Risk Map shows:

• “Areas not served by the Combined Sewer and Stormwater Collection System” - showing where data for rainfall driven storm runoff is not available, and where flood risk has not been analyzed.
• “Historical Shoreline”, “Historical Creeks”, and “Historical Waterbodies” - historical hydrology layers to illustrate the general topography of low-lying areas in the City.
The Horizontal Datum used for the GIS layers is “NAD_1983_2011_StatePlane_California_III_FIPS_0403_Ft_US.”

Notes on Usage

At a minimum, the 100-Year Storm Flood Risk Map is updated by the San Francisco Public Utilities Commission (SFPUC) on an annual basis on or before July 1 to account for any parcel review requests that remove properties from the Flood Zone. To confirm the latest version of the 100-Year Storm Flood Risk Map, check the SFPUC website at https://sfpuc.org/learning/emergency-preparedness/flood-maps to see if the map has been updated since the date of this shapefile or if there have been any parcel review determinations that identify parcels that are no longer part of the 100-Year Flood Risk Zone. The most recent official map, associated documentation, and list of parcels removed from the map from a parcel review process are available at https://sfpuc.org/learning/emergency-preparedness/flood-maps. Please be advised that the parcels listed are no longer considered to be within the 100-Year Flood Risk Zone as a result of the parcel review process. As of July 2022, this list is updated on an ongoing basis. Check the SFPUC website for any changes to this schedule.

The boundaries of this zone align with San Francisco parcel boundaries. The user should confirm proper projection or use of the webmap at https://sfpuc.org/learning/emergency-preparedness/flood-maps to properly identify parcels within the flood zone.