Chehalis Dam

Jabb

New Member
#1
Wondering what the best way is to tell my elected officials that I do not want a dam on the Chehalis. Who have you guys contacted?

Looks like the current plan is for a 300 ft. tall dam in the headwaters area above Pe Ell on Weyerhaeuser property that will be claimed as eminent domain by the state.

All photos below in area to be flooded by dam reservoir:









If you'd like to learn more about the dam, this 700 page document should do it for you:
http://chehalisbasinstrategy.com/wp...d-Dam-Fish-Passage-Design-Report_COMPILED.pdf




 

Old406Kid

Active Member
#4
I think it's all based on a 2007 storm that flooded I-5. Seems crazy to me that a dam is the idea they came up with, seems like the only long-term solution to flooding along I-5 is to move infrastructure out of the floodplain.
Sounds like somebody should have thought about that beforehand if that's the case.:confused:
 

Stonefish

Triploid, Humpy & Seaplane Hater
#5
I think it's all based on a 2007 storm that flooded I-5. Seems crazy to me that a dam is the idea they came up with, seems like the only long-term solution to flooding along I-5 is to move infrastructure out of the floodplain.
Or not build in the floodplain.....

We had a prime example just recently that even though a river is damned, you can still have flooding.
Really foolish plan.
SF
 

Salmo_g

Well-Known Member
#6
There was a comment period to the Department of Ecology's environmental document a few months ago. Can't remember when I did that. The dam proposal is fuckin' crazy. The Corps won't touch it because it fails the required federal cost:benefit analysis. The state and local governments would have to take it on, and frankly, nobody's got the money to waste. But there is a lot of local political push for it, so lobby your county commissioners (who are probably already on the take for it), DOE, and the governor's office with your opposition. Tell 'em to just say no to pissin' away your tax dollars, and avoid the environmental destruction that the project would cause as well.

Sg
 

Buzzy

Active Member
#7
I think it's all based on a 2007 storm that flooded I-5. Seems crazy to me that a dam is the idea they came up with, seems like the only long-term solution to flooding along I-5 is to move infrastructure out of the floodplain.
I'm not sure what you mean by "infrastructure" removal. There certainly were many structures flooded; commerical and residential. Are you suggesting that structures be removed from the floodplain? The freeway is obviously in the flood plain of record.



I haven't read any studies of causes for the flooding. No doubt 14-20 inches of rain; unprecedented, was the lead cause but what are the drainage basins like? Did logging contribute? Upstream development? Climate change?

I don't want to read the 700+ pages of the link you provided but a brief look at the "dam" doesn't show a powerhouse (image you provided). So is this dam to be at extreme low forebay elevations so it can capture flood events or is there a powerhouse segment? I see a stilling basin on one of the images you provided but that could be an entrance for the fish passage facility. Are fish going to be passed upstream when the forebay is low? Or a 300 foot high fish ladder?

Anyway, I hear you and feel your pain, sincerely. Sg is right, write your congressmen and write the Governor. Raise hell. A letter a week! And thank you for sharing this.
 
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Jim Wallace

Smells like low tide.
#8
Planners fucked up when they failed to foresee the flooding that can happen where I-5 runs. Now they want to build a damn to try to fix the problems they created with their pathetic "undersight."
And I would not be surprised to learn that Weyerhauser has logged every basin and slope in the area that they could get to, no matter how steep.
 

Salmo_g

Well-Known Member
#9
Buzzy,

The powers that be in Lewis County couldn't pass up the opportunity to develop floodplain land alongside I-5, and thereby exacerbate pre-existing flood risks. I-5 creates a partial dike in the floodway, but a couple creek crossings allow floodwaters to back up in much, if not most of the traditional flood plain.

Because of the knowing stupidity in allowing continued development within the flood way and flood plain, I have developed the biased opinion that the area should be allowed to flood as high and as often as possible, because stupidity should hurt.

The cause of flooding in the Chehalis basin is all the usual reasons. It has always flooded. Floods of specific magnitudes occur more frequently because of logging in the watershed mainly, but also due somewhat to the usual suspects of road construction, agriculture, and urbanization.

The proposal includes 4 options as I recall, one of them with associated hydro, but that reduces floodwater holding capacity. And of course, without hydro or urban water supply, a single use, flood control only dam is a flat out huge waste of money under any objective cost:benefit analysis. The only way this dam gets built is if the Lewis Co. movers and shakers can swindle "other people's money" from other cities and counties. Lewis Co. can't afford it on their own. And if put up to a Lewis Co. vote, it wouldn't pass because most of the county's population has the good sense not to live in the Chehalis River flood plain.

Upstream and downstream fish passage options depend on which of the 4 alternatives is eventually selected. The no-action alternative is the only cost effective alternative for every citizen who doesn't own prospective development property in the flood plain who is hoping to make a killing by using other people's money.

That's my objective analysis. You should see my biased one.

Salmo g.
 

cabezon

Sculpin Enterprises
#10
Hi Buzzy,
The flood occurred in two stages. The first stage impacted the upper valleys of the Chehalis system, such as near Pe Ell. This flooding was triggered by massive landslides and debris flows from steep slopes that were clear-cut by Weyerhauser. The debris created transient dams that flooded farmhouses and damaged roads and other infrastructure. The state had allowed Weyerhauser's in-house geologists to certify that the slopes were O.K. An unbiased geologist would likely have blocked logging on the steep slopes.
The second stage occurred along the main-stem river. The volume of water from the western Chehalis branches and the eastern tributaries exceeded the ability of a relatively low-gradient, shallow river basin to carry this water away. The flat land between the hills to the east and west, which you can see as you drive along I-5, is part of the natural flood plain for the river. Lax zoning by the cities of Chehalis and Centralia and Lewis County permitted housing and industrial development along the eastern fringes of the flood plain. Then the big-box mega-malls were approved, each built on a pad of fill higher than the next, an implicit acknowledgement that they were building in the flood plain. The volume of the pads probably reduced storage capacity of the flood plain [a five-gallon bucket with a brick in it cannot hold five-gallons anymore], exacerbating the flooding to the fringe areas. In addition, logging in the upper basins and asphalt and development in the area reduced the ability of the area to hold rainfall through infiltration; that led to too much water being dumped into the basin all at once = record flooding.
There is a small cabal of powerful individuals in the Chehalis/Centralia area that want to see federal dollars used to reduce the flooding risk. They believe that this will allow further development to occur in the flood plain and spur economic growth (and profits to a select group of individuals) in the area. They will use rhetoric about the economic impact on the region from the closure of I-5. But if this was the major concern, I-5 could be secured at FAR less cost by extending/expanding the levees along the freeway. But this is likely to increase the flooding risk for everyone else (this water has to go somewhere) and not help their development ambitions. The whole thing does not pass the smell test.
Steve
 
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Buzzy

Active Member
#11
Buzzy,

The powers that be in Lewis County couldn't pass up the opportunity to develop floodplain land alongside I-5, and thereby exacerbate pre-existing flood risks. I-5 creates a partial dike in the floodway, but a couple creek crossings allow floodwaters to back up in much, if not most of the traditional flood plain.

Because of the knowing stupidity in allowing continued development within the flood way and flood plain, I have developed the biased opinion that the area should be allowed to flood as high and as often as possible, because stupidity should hurt.

The cause of flooding in the Chehalis basin is all the usual reasons. It has always flooded. Floods of specific magnitudes occur more frequently because of logging in the watershed mainly, but also due somewhat to the usual suspects of road construction, agriculture, and urbanization.
Hi Buzzy,
The flood occurred in two stages. The first stage impacted the upper valleys of the Chehalis system, such as near Pe Ell. This flooding was triggered by massive landslides and debris flows from steep slopes that were clear-cut by Weyerhauser. The debris created transient dams that flooded farmhouses and damaged roads and other infrastructure. The state had allowed Weyerhauser's in-house geologists to certify that the slopes were O.K. An unbiased geologist would likely have blocked logging on the steep slopes.
The second stage occurred along the main-stem river. The volume of water from the western Chehalis branches and the eastern tributaries exceeded the ability of a relatively low-gradient, shallow river basin to carry this water away. The flat land between the hills to the east and west, which you can see as you drive along I-5, is part of the natural flood plain for the river. Lax zoning by the cities of Chehalis and Centralia and Lewis County permitted housing and industrial development along the eastern fringes of the flood plain. Then the big-box mega-malls were approved, each built of a pad of fill higher than the next, an implicit acknowledgement that they were building in the flood plain. The volume of the pads probably reduced storage capacity of the flood plain [a five-gallon bucket with a brick in it cannot hold five-gallons anymore], exacerbating the flooding to the fringe areas. In addition, logging in the upper basins and asphalt and development in the area reduced the ability of the area to hold rainfall through infiltration; that led to too much water being dumped into the basing all at once = record flooding.
There is a small cabal of powerful individuals in the Chehalis/Centralia area that want to see federal dollars used to reduce the flooding risk. They believe that this will allow further development to occur in the flood plain and spur economic growth (and profits to a select to group of individuals) in the area. They will use rhetoric about the economic impact on the region from the closure of I-5. But if this was the major concern, I-5 could be secured at FAR less cost by extending/expanding the levees along the freeway. But this is likely to increase the flooding risk for everyone else (this water has to go somewhere) and not help their development ambitions. The whole thing does not pass the smell test.
Steve
Thanks gentlemen for your explanations and wisdom, not only on the flood and its causes, but on this "damn dam" (this coming from a former dam guy). Very interesting indeed.

By the way @Salmo_g, would love to see your biased opinion!
 

freestoneangler

Not to be confused with Freestone
#12
So what are the odds of this proposed dam becoming reality? I would venture to guess that most of the residents in this area are tired of the repeated flood events and like the idea?

There is a small cabal of powerful individuals in the Chehalis/Centralia area that want to see federal dollars used to reduce the flooding risk.
Who are these individuals? "Powerful individuals (in the context of government manipulators) in the Chehalis/Centralia area..." a description and location that don't outwardly jive.
 

Rob Allen

Active Member
#14
I am sorry I know that new projects get proposed every few years in the PNW but i don't think any of them have a snowballs chance in hell to ever get built. So i am not worried about this one.
 

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