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
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
Inflated, deflated and false information provided by
DWR since 2005:
|The map below gives an accurate account of historic Delta
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.
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
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!
Sacramento River Flood Control System.pdf
Sacramento Valley Flood Control System.pdf