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[Morty]

In an attempt to learn a little more about our favorite part of the Fraser (and avoid running aground yet again) I was reading a report on Minto Channel from UBC Dept of Geology.
Historical Changes of Minto Channel during the Twentieth Century
Part of that was so amazing I just have to share.   The following relates to: gravel and rocks moved by the river water.
 
"we know that the average annual transportation of material past the Agassiz-Rosedale bridge is in the order of 200,000 tonnes... that is material larger than 2mm, that is all material larger than sand..."
"the bed material transported downstream from the mouth of the Harrison river is less than 100,000 tonnes per year, on average."  

That means that there is 100,000 tonnes of aggregate accumulating each year between Rosedale and the Harrison. (200,000 past Rosedale less the 100,000 that passes Harrison)

"Such  material when piled 5 metres deep would occupy a square measuring 110 metres on each side."

It's not surprising that we can already wade across at Peg Leg.  It sure would be helpful if that were dredged again.

[alwaysfishn]

It's not surprising that we can already wade across at Peg Leg.  It sure would be helpful if that were dredged again.

From what I understand it is unlikely that that channel will be dredged. That's why they created the new channel about 100 yards downstream from the current channel. Probably to minimize the erosion on the banks in the current channel.

[Gaffer]

In an attempt to learn a little more about our favorite part of the Fraser (and avoid running aground yet again) I was reading a report on Minto Channel from UBC Dept of Geology.
Historical Changes of Minto Channel during the Twentieth Century
Part of that was so amazing I just have to share.   The following relates to: gravel and rocks moved by the river water.
 
"we know that the average annual transportation of material past the Agassiz-Rosedale bridge is in the order of 200,000 tonnes... that is material larger than 2mm, that is all material larger than sand..."
"the bed material transported downstream from the mouth of the Harrison river is less than 100,000 tonnes per year, on average."  

That means that there is 100,000 tonnes of aggregate accumulating each year between Rosedale and the Harrison. (200,000 past Rosedale less the 100,000 that passes Harrison)

"Such  material when piled 5 metres deep would occupy a square measuring 110 metres on each side."

It's not surprising that we can already wade across at Peg Leg.  It sure would be helpful if that were dredged again.

Just think about it for a second---- remove all the gravel ( let's call it the Great Harrisson Plug ) from the Fraser river How far south of the fraser would the NEW Harisson river go Inland before the whole NEW Harrisson Lake  level stabilized? There's a reason for everthing under the sun------ cheers

[Morty]

Just think about it for a second---- remove all the gravel ( let's call it the Great Harrisson Plug ) from the Fraser river How far south of the Fraser would the NEW Harrison river go Inland before the whole NEW Harrisson Lake level stabilized? There's a reason for everthing under the sun------ cheers

Nobody before you wrote anything about removing "all the gravel".

Seems logical to me though that there could be a harvest of the additional 100,000 tonnes that arrive each year.  If done correctly, it could actually create more productive spawning areas.  As it was, this Spring, Minto channel pretty much dried up.  That means that any spawn that was there dried up and died.

There is also the consideration that some fishes need a certain depth of water for spawning.  If the channel is getting progressively wider and shallower those spawning areas are being lost anyway.  By dredging the middle parts, where fish are unlikely to spawn anyway, we could create a broad range of depths and accommodate a wider range of species that are native to that section of river.

[Sterling C]

Nobody was removing gravel from the river for thousands of years before and everything worked out ok. I don't buy that we suddenly need to start removing gravel to restore balance. 

[Sam Salmon]

Once the Fraser was dyked-once any river is dyked-everything changes and never for the better.

The Chilliwack-Vedder system is for all intents and purposes a ditch that people keep struggling to control and the Fraser is prety much a  bomb waiting to go off.

[marmot]

Biffchan.. I agree with you a thousand times over.  We tinker far too much with forces waaay beyond our control.

[Sir Snag-A-Lot]

Yet we all drive on roads to get to our fishing locations.  These roads are all lined with gravel.  It has to come from somewhere. 

With our rapidly growing population the public is constantly calling for infrastructure improvements/expansion.  There is no way to get the gravel required for this work without some form of habitat destruction for some species.  Open pit gravel mining is bad too.  Just look at the Coquitlam River valley for evidence of this.

What is really needed is for more studies to be done to assure that the negative impact of gravel extraction is minimized.  With the Fraser River having such a varied population of fish spawning year round, it seems to me that there is no safe way to do it there.

In terms of artificially controlling the river to maintain spawning channels, we need to take a longer-term perspective.  The Fraser from Chilliwack to near Hope is classified as a "wandering-gravel bedded river".  As such its bars and islands are only temporary features.  They are naturally abandoned, infilled, new ones are cut and old ones are reactivated over the scale of tens of years.  Habitat is lost and habitat is gained.  In the long run it is all in balance as long as human interference doesn't tip the system out of equilibrium.   

[Morty]

Nobody was removing gravel from the river for thousands of years before and everything worked out ok. I don't buy that we suddenly need to start removing gravel to restore balance. 

Please don't write such exaggerated statements until you've done some research.

Active dredging took place in Minto channel every year from the mid 40's until 1996.
Dredging was also done all the way to Hope to allow tugs to gather log booms & bundles.  Also all the way to Harrison Lake for the big supply boats as early as the Gold Rush.

[Gaffer]

Nobody before you wrote anything about removing "all the gravel".

Seems logical to me though that there could be a harvest of the additional 100,000 tonnes that arrive each year.  If done correctly, it could actually create more productive spawning areas.  As it was, this Spring, Minto channel pretty much dried up.  That means that any spawn that was there dried up and died.

There is also the consideration that some fishes need a certain depth of water for spawning.  If the channel is getting progressively wider and shallower those spawning areas are being lost anyway.  By dredging the middle parts, where fish are unlikely to spawn anyway, we could create a broad range of depths and accommodate a wider range of species that are native to that section of river.

As a past director for the Fraser River Gravel Stewardship Committee that tried unsuccesfully to have the Prov'l Gov't authorize the Gravel Grab from the Fraser over the last 5 years and with accumulated data of 4 accredited scientists saying that there is NO Appreciable  Aggradation of Gravel (Adding to what's already there) in the Mid -upper Fraser. The Fraser Canyon Ain't making any new gravel ! What's there now is all there is ever going to be . To be sure after the Gravel Grab from the likes of Herrling and Big Spring Bars and the remnants of those bars are moving downstream But to say 100,00 TONNES of gravel arrive EACH year is erroneous i If you want the Facts-- send me an e-post I've got lots of Real facts not hearsay---Cheers 

[Morty]

As a past director for the Fraser River Gravel Stewardship Committee that tried unsuccesfully to have the Prov'l Gov't authorize the Gravel Grab from the Fraser over the last 5 years and with accumulated data of 4 accredited scientists saying that there is NO Appreciable  Aggradation of Gravel (Adding to what's already there) in the Mid -upper Fraser. The Fraser Canyon Ain't making any new gravel ! What's there now is all there is ever going to be . To be sure after the Gravel Grab from the likes of Herrling and Big Spring Bars and the remnants of those bars are moving downstream But to say 100,00 TONNES of gravel arrive EACH year is erroneous i If you want the Facts-- send me an e-post I've got lots of Real facts not hearsay---Cheers 

Ain't erroneous - I posted the title of my research document in the original post.

[chris gadsden]

Gaffer has this right all the way in his comments. The bottom line is those that know the Fraser River well know that you will never take enough gravel out to prevent a major flood, it is just way too big. It is just a government shame all the way and what they say cannot be believed just like every thing else we now know about them after the recent election.

As well a study commissioned by the government even back up what I said in my second sentence. The gravel removal program is just another assault on our precious fish stocks and their habitat, very sad. The bright side however is we have many energetic people willing to spend countless hours on trying to halt this, for the benefit not only for the salmon but you and me too.

[speycaster]

The Fraser was fine until all the a$$holes arrived and started changing the landscape. Get rid of a million and a half a$$holes from the lower Fraser and the river will recuperate. So every one should do their part and not procreate, plus kill a few a$$holes each.