Delta Flood Maps

Maps from Reports regarding Delta Islands, the levees and historical floods of the Delta
The history of flooding in the Delta is a current media focus, as the state wants us all to believe the levees are about to fail. However, if one reviews the history of the levees, since they were improved to current standards, one finds there have not been that many failures. One also realizes that since 2005 the State of California has been publishing incorrect and false Delta flood history data and maps, and reporting flooding of areas NOT located in the Delta as if those flooded areas were in the Delta. The state has been doing this in its effort to convince politicians and the general public that the Delta must be "fixed"....NOW! Why is island flood history so important? Because the state is trying to validate which islands to force the farmers into "restoration" plans, which islands they might try to eminent domain if they don't have "willing sellers", and they base their assumption of future possible levee failure on past records, but use false information. See the story of Ryer Island as one example. Update 2/25/2011: We've added a video covering flood history of the Delta. Also see: Timeline_delta_levee_failures.pdf and the graphic showing the timeline Note that some Delta Islands are designated "flood control" islands 1975_delta-floods-dwr.pdf
Reality: Historical Data	Inflated, deflated and false information provided by DWR since 2005:
The map below gives an accurate account of historic Delta Island floods or levee breaches since the levees were improved to current standards. There have been at most 33 incidents of levee breaches and/or island flooding since the levees were improved to the current configuration.	The map below was compiled by URS for DWR's Delta Risk Management Strategy report, and since they wanted to make it look like the Delta is much more likely to flood than it is, they added in records of islands not even located in the Delta, and also added flood history from before the islands were actually reclaimed to the current standards. So when you read reports that Delta islands have flooded "168" times that is entirely FALSE. Look to the US Army Corps of Engineers 2006 Report to Congress (to the right) and you will see correct data.
100_yr_flood-delta.pdf 1975_delta-floods-dwr.pdf	Elevation-Inundation-Subsidence_InteractiveMap.pdf ***Note this map shows incorrect flood and seismic risk
Compare the map below from a 2006 DWR-Berkeley project to the map to the left. The map below doesn't include the Suisun Bay and the map to the right does.	Another problem with the URS/DWR merging of records is that who ever compiled the Suisun Bay information with the Delta information did not realize that there are two Ryer Islands in Solano County. The records of the Ryer Island in Suisun Bay, which has an ongoing restoration project, was merged with the much larger Ryer Island north of Rio Vista. Then DWR took the Suisun Bay Ryer Island off its maps, so uninformed scientists utilizing URS/DWR data would not even be aware of the problem. DWR was advised of the incorrect data in 2008, and by the end of 2010 has only acknowledged the mistake as to Ryer Island flood history...the rest "takes time to correct". (See the Ryer Island story)
Below is another map found in a DWR publication regarding the Delta. This one clearly shows DWR's pre-2005 records of Delta flooding, using 1967-2004 as the logical timeline because the levees of the Delta were set to their current configurations and levels by 1967.	The next map below shows DWR's accounts of when the Delta Islands were reclaimed. Its wrong based on historical records, but even if it was right, why would DWR use "historical inundation since 1900" for the above map when DWR knows at least one third of the islands were not even reclaimed until the 1910's. In addition, islands listed as "controlled flooding" islands are counted. The only possible answer is that DWR wanted to make the Delta levees look more susceptible to failure than they really are.

Levee failure and island inundations are important factors utilized to calculate the "seismic risk" of each Delta Island. But even DWR recognizes that in the past, the levees have not failed due to earthquakes in Northern California. (click on the page copy below). In any case, to calculate risk of Delta island breach or flood, one needs to start with the correct historical data.	One has to wonder if ANY of the "modeling" using combined Suisun Bay and Delta data is correct, if the basic information input into the models started out WRONG!
The map below shows DWR records of Delta flood history before 1967, but does not show any records prior to 1932...why? Because it is misleading to use flood records for islands that did not actually have the levees built before then. That would be like assessing the risk to a building before the building was even there!
maps/islands_floods_levees/Comparison_of_Major_Levee_Breaks_in_Delta.pdf maps/islands_floods_levees/corps_oma_manual_for_east_bypass_levee_to_miner_slough.pdf maps/islands_floods_levees/DRMS_Risk_Report_section_09.pdf maps/islands_floods_levees/drms_s7_86floods.pdf maps/islands_floods_levees/dv_wrong_maps-Ryer-Andrus.pdf maps/islands_floods_levees/Elevation-Inundation-Subsidence_InteractiveMap.pdf maps/islands_floods_levees/Fina_Brannan-Andrus_LM_Dist_13_PL_84-99_Sites_BO.pdf maps/islands_floods_levees/Final_critical_levee_repair_BO_062106_with_appendices.pdf maps/islands_floods_levees/flood_photos_usace.pdf maps/islands_floods_levees/floodmgmtimplementation20091015.pdf maps/islands_floods_levees/Floodplain-dpc-revised2010.pdf	maps/islands_floods_levees/new_hope_tract2006.pdf maps/islands_floods_levees/north_ryer.pdf maps/islands_floods_levees/Pacific Historian1959_delta_history.pdf PlateMapPrioritiesProjects.pdf maps/islands_floods_levees/Plate_61.pdf maps/islands_floods_levees/Plates_061-090.pdf maps/islands_floods_levees/post_flood_assessment.pdf maps/islands_floods_levees/preliminary_100_and_200_year_floodplain.pdf maps/islands_floods_levees/project levees.pdf maps/islands_floods_levees/Project_Map-sac.pdf maps/islands_floods_levees/R_207JLMap2_2.pdf maps/islands_floods_levees/rec_dist_offices.xls maps/islands_floods_levees/reclaimed_compared.cdr maps/islands_floods_levees/reclaimed_compared.pdf maps/islands_floods_levees/ryer_flood_map_risk_study.pdf maps/islands_floods_levees/ryer_history-June 1995.pdf maps/islands_floods_levees/ryer-1996flood-no.pdf maps/islands_floods_levees/ryer2006.pdf maps/islands_floods_levees/sac_e2.pdf maps/islands_floods_levees/sac_flood_history-detailed_usace.pdf maps/islands_floods_levees/sac_impact_areas.pdf Sacramento River Flood Control System.pdf Sacramento Valley Flood Control System[1].pdf maps/islands_floods_levees/SacramentoRiver_LFPZ_Map.pdf maps/islands_floods_levees/sacriver_flood_control.pdf maps/islands_floods_levees/sactoriverbasin2of4.pdf maps/islands_floods_levees/SanJoaquinRiver_LFPZ_Map.pdf Seismology_TM-2010_online_version.pdf maps/islands_floods_levees/shd_floods.cdr maps/islands_floods_levees/sol_c3.pdf SPFCDescriptiveDocNov2010AttachA.pdf maps/islands_floods_levees/staten-IN-Delta_storage.pdf maps/islands_floods_levees/steamboat_design_flood_flow.cdr maps/islands_floods_levees/steamboat_design_flood_flow.pdf maps/islands_floods_levees/steamboat_design_flood_flowQ.pdf maps/islands_floods_levees/StudyAreaMap.pdf maps/islands_floods_levees/tyler_island.pdf maps/islands_floods_levees/U.docx usace_delta_flood_history_2007_report_to_congress.pdf usace_delta_floods_as_of_2006.pdf usace_flood_hist_rec-Ch5Fig.pdf usace_flood_history2002.pdf usace_flood_risk.pdf maps/islands_floods_levees/usace_flood-timeline.pdf maps/islands_floods_levees/usace_levee_maps.pdf maps/islands_floods_levees/usace_priority_areas_2007.pdf maps/islands_floods_levees/USACE_request_for_corrections.cdr maps/islands_floods_levees/usace-Ch6Fig.pdf maps/islands_floods_levees/usbr_drms_use2009.pdf maps/islands_floods_levees/usbr_flood_hist.pdf maps/islands_floods_levees/usr_island_inundation.cdr maps/islands_floods_levees/walnut_grove_levee.pdf maps/islands_floods_levees/west_sac_levees.cpt