Were Did All The Gravel Come From?

[Phil Lilley]

We talked awhile back about the upper portion of the tailwater filling in with gravel and someone asked where did the gravel come from. Well I haven't been over to outlet #1 in a while but today I noticed this.

From the first pic, the view is from the top looking down the outlet. You can see the path the water used to take- pretty much straight down the hill and to the lake. Now it bends to the right and has cut the bank out to the tune of about 30-35 feet in and 8 feet high. That's alot of gravel!

I asked Leonard, who was with me, why did this bank suddenly decide to erode all of a sudden? 50 years of generation and in less than a year it did all this.

Anyone have a take on it?

Regardless, all this gravel is now sitting between outlets #1 and #2 I believe. And if the bank continues to wash, the area all the way down to rebar will fill in.

Water will find a way. Maybe it will wash on down to the dry bar or further downstream. Who knows. Question is... does MDC just let it go and settle where it wants to or do they shore up the bank and stop the bleeding.

Indeed, it is a situation that's new and will get worse.

[Danoinark]

Very good question and one that should probably be addressed by TU, Sat, Feb 23 at its next meeting. Meeting starts at 7pm. I hope a lot of new folks show up. Its also election time.

Meetings are held at the Shephard of the Hills Hatchery.

Much more water coming down that hill as it cuts into the bank and the big browns might just use it for a spawning run next fall.

Dano

[Trav]

Water is the most powerful force on the planet. The Gravel isnt just appearing or being washed down stream. It is evolving and changing. Breaking down.

Anyone who has a garden in these here hills will tell you, that rocks and gravel just work thier way to the suface. Believe it or not, the gravel your seeing pile up below the dam is actually coming from the foundation of the dam itself.

My Great Uncle was a worker when they built the dam and he had told many a story of how dangerously and unprepared the engineers were when building it. There is alot of sediment under that dam. It has to come out somewhere. Now your seeing the same rock that built the dam move out from under it.

Haha, Scary thought huh? But its true.

[snagged in outlet 3]

Shufflers?

SIO3

[Guest]

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[vanven]

If I remember correctly I first noticed the shore washing away last January during a period of very heavy water release. I almost stepped into the hole and I guess it was probably 10 feet deep at the time. It was a sheer drop off just a couple of feet into the water. Since then it has eroded away to a much less severe angle.

-Jerod

[Leonard]

I think personally there was a couple of reasons.

first, High generation this past spring (2007), They run alot of water for a long time.

second. Increased flow after outlet 3 was shut down to build the ladder.

third. I know guys moves the rocks around in the outlets, to change the flow and direction of it.

Here is a picture of what the bottom of the outlet liked like in late summer (2006)

the outlet use to be about 6-9in deep and you were able to jump across it.

[Trav]

As Leonard stated, there probably is a number of factors, Lets not forget, that the new overflow area near moonshine loosened alot of gravel as well.

[Phil Lilley]

"ets not forget, that the new overflow area near moonshine loosened alot of gravel as well." ???? That's a mile away...

Leonard- we had flows- 4 units full and even flood gates numerous times in the 80's. We'd have 6-7 months straight with NO down time of 4 units.

But one thing you mentioned make more sense- the increased flow from shutting off #3.

I sent an email to a couple of MDC folks with my concerns and a link to this topic. I'll ask if the flow was increased.

I'd say they don't know anything about the wash and I'm not sure if they'd be interested in doing anything about it. Not sure what they could do short of spending alot of money shoring up the outlet.

But it makes my point about the upper end filling in where there are no deep areas to hold big trout anymore.

[Greg]

Phil (or anyone else) - what was the reason or rationale for shutting off #3? I actually liked fishing that area a little better when there was some flow there.

Greg