california FEMA effective is here
https://transparentgov.net:3200/googlemaps/default?layer_id=5&layer=FEMA+Effective¢er_lat=33.817694946675125¢er_long=-116.5243829989038¢er_zoom=14&url=https%3A%2F%2Fgis.water.ca.gov%2Farcgis%2Frest%2Fservices%2FBoundaries%2Fbam_viewer%2FMapServer&overlayType=overlayType_image&panto=0
california designated floodway is here
https://transparentgov.net:3200/googlemaps/default?layer_id=19&layer=Designated+Floodways¢er_lat=36.188269356983284¢er_long=-119.13646322346341¢er_zoom=9&url=https%3A%2F%2Fgis.water.ca.gov%2Farcgis%2Frest%2Fservices%2FBoundaries%2Fbam_viewer%2FMapServer&overlayType=overlayType_image&panto=0
california flood map REST api endpoint is here
https://transparentgov.net/json2tree/esri/server2/folder.html?org=https%3A%2F%2Fgis.water.ca.gov%2Farcgis%2Frest%2Fservices&url=https%3A%2F%2Fgis.water.ca.gov%2Farcgis%2Frest%2Fservices&arcgis_online_token=&select_folder=467&select_layer=19
Official california flood map is here
https://gis.bam.water.ca.gov/bam/
download california river stream from here
https://hub.arcgis.com/datasets/248c535bb8e5404ab987b5178445b7b8/about