🚀 go-pugleaf

In article <2991832636.2.p01274@psilink.com>, "Tom" <p01274@psilink.com> writes:
...
|> For those of you unfamiliar with the Sacramento area, Natomas is a 
|> suburb of Sacramento, north of the American River.  While it is true 
|> that much of Natomas is undeveloped, much of it is - with high density 
|> residential housing.  These people are in the 100-year flood plain, and
   ^^^^^^^^^^^^^^^^^^^
This "high density residential housing" was/is being built on the developer's reliance that the State & Federal Governments will somehow bail them out of their investments in the Natomas flood basin (by building a Dam, increasing the size of Leve's etc...). And, in order to hold the residents of the flood basin hostage to developer's agenda. 

|> a levee breach would put water up to their rooftops.  So, while much of 
|> the driving force behind a dam project is the development of Natomas, 
|> there is a genuine public safety component there also.
                      ^^^^^^^^^^^^^^^^^^^^^^^
Yes, and this public safety component is no accident. In fact, it strikes me that perhaps the same developers who sold the public this housing in the flood-plain should be required to pay the cost of moving that housing to higher ground. 

|> >This flood basin is not yet a fully developed 
|> >part of Sacramento, but rather, an area that developers want to continue 
|> >build on.  It's the developers that want to build this dam. The 
|> >developers stand to gain Billions in windfall profits if they can develop 
|> >the flood-basin/wetland/swampland. It's one of the oldest stories of 
|> >California water politics played over yet again, except in this case they 
|> >want to build on the swamplands instead of the desert.
|> Yes, probably true.  But it is the announced intent of SAFCA (Sacramento 
|> Area Flood Control Authority) to get the Natomas area out of the flood
                                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|> plain, irrespective of the means.  Here the question is the level of 
   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
I already pointed out that the only way to get the Natomas basin out of the flood plain is to teleport it somewhere else. :-) The only way to eliminate the danger IMHO is to move the housing out of Natomas onto a higher elevation.

|> protection.  If other means (levees, tinkering with Folsom, diversion 
|> to the south) are used to get Natomas out of the flood plain, the level 
|> of protection there is likely to protect for less than a 200-year 
|> return interval flood.  As the Mississippi/Missouri floods last year 
|> demonstrated pretty well, these very large (500-year) floods are not 
|> some hydrologist's wet dream.  They can really happen.  Saint Louis had 
|> a 200-year plus floodwall that came within 0.8 foot of overtopping.  
|> That's why a very high level of protection for urban areas is always 
|> desirable, but is not present at Natomas (or Sacramento for that 
|> matter).  Your basic dam can protect against these infrequent floods.

Not the Auburn dam. The Auburn Dam doesn't prevent interior flooding in the Natomas Basin. During the Auburn Dam hearings, enough rain fell in Natomas to cause 2 feet of flood waters to rise in the streets. 

The cause wasn't the North Fork of the American River rising, or even Folsum dam, or the American downstream of Nimbus; It wasn't the Yuba or Feather Rivers flooding, or even the Sacramento; It wasn't _any_ watershed overtopping it's flood protection...

It happened at the end of a multi-year drought, and it was due to interior flooding, i.e. Rainfall in Natomas just didn't have anywhere to flow. Natomas is a flood basin... what goes in stays in unless you pump it, let it evaporate, or seep out. Not to mention that the storm drains hadn't been cleaned out. :-)

So SAFCA wants us to build a Billion to build a dam, yet they can't even keep the storm drains clean in Natomas... hummm...

|> 
|> >How about those that currently recreate on the river that this dam 
|> >would bury under silt? How about those that own land that would be 
|> >condemed. How about the gold miners that would lose their livelyhood? 
|> >How about the loss of a fantastic stock of native Rainbow trout? How 
|> >about drowning an area that is just now begining to support Bear & 
|> >Mtn Lion populations again?
|> All true.  Does a dry dam (pool fills only during floods) engender the 
|> same objections? 
|> 

Yes, the same objections, and objections regarding the water storage argument as well (i.e. that's what started this discussion in ca.water after all).

|> >And what about the fools who buy property that is "protected" by this 
|> >behemouth that are flooded out when the Sacramento River overflows its 
|> >levees, and the drainage system in Natomas plugs up?
|> Well, you've got other behemoths like Shasta and Oroville that are 
|> supposed to keep the Sacramento River from flooding.  The Natomas 
                        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Nope, these are multi-purpose water storage dams, not flood control dams.

|> drainage system will plug up if it's not maintained.
   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Just my point. Let's maintain what we've built, not build a Billion dollar pork project for the Natomas developers.


-- 
Michael K. Poimboeuf mkp@sgi.com aka Bionic Boof
Silicon Graphics Inc. Mtn View California
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"The trick to learning to fly, is to throw yourself
at the ground and miss." - Douglas (not Doug) Adams -
Oh yes, and remember to have your towel handy.
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