Lower Crow

[fisher26]

I was fishing the lower crow the other day and noticed that there was lots and lots of silt covering most of the river. I am sure this large amount of silt cannot be good for any river as it’s not good for spawning trout. It could even it could harbor a concentrated and deadly population of whirling disease. I read in an old post on FFA about the Oldman river dam having something to do with the large amount of silt in the lower crow, but how could a dam effect that? Is this a similar problem on the lower Oldman and Castle?

 

 

The Oldman dam was such a terrible waste of what sounded like three amazing trout streams the government should take action to improve the amount of silt (I have no clue how this could be done) in the lower river(s).

[Grizz]

I used to fish the area around Todd Creek alot. Last time I was there it was silted to *hit too and fishing suckeded!

 

I noticed all the silt on what was previously nice gravel and boulders... I just adjusted by moving upstream to fish. Although the reservoir makes sense as the velocity of the water decreases, it will drop it's entrained load sooner... I thought of the same thing.

 

I never did find out if it was the actual cause of the change in that area though.

[Castuserraticus]

The cause is likely natural. When core studies are done of ancient and modern stream deposits, we virtually always see alternating mud and coarser deposits. The changes are commonly very abrupt. Streambeds are not stable environments on any geological time scale.

 

As indicated by Griz, fishermen tend to be quietly happy when a new pool or drop off is formed by in-channel migration of bedforms and erosional down cutting and cry the blues when the same processes obliterate our favourite spot.

 

A sudden influx of a different sediment (mud in a gravel system or vice versa) is not likely to last. It indicates either a change in flow velocity (eg low water or flood) or sediment supply (eg landslide or large bank sloughing). The river will return to it's equilibrium state unless the change is massive.

[fisher26]

Great post thanks, there is lots of construction in the pass so maybe that's the casue, if so it likley won't improve it may even get worse... So after run-off there is more or less silt in the streambed?

[Hawgstoppah]

If you were to ask me, having spent my years on the Crow, both before and after the dam damn was built... I would say that the silt in question is NOT a natural thing, and likely caused by the lake and the river water slowing down to meet it. Now it's very silty and mucky all the way up to the area locals refer to as horseshoe bend, but above that point, it remains quite sediment free.... unexplainable unless it's due to the lake in my opinion..

[fisher26]

Hmmm, did you find it was harder to catch fish where there was more silt? Because technically fish spawn further up where the silt problems are better or non-existent so it isn’t effecting most spawning.

[Hawgstoppah]

Hmmm, did you find it was harder to catch fish where there was more silt?

 

Yes. Either they simply weren't there.... or I did not change my strategy enough to find out what bugs they were eating that were in the silt (you'd have figured a sjw / bloodworm combo would work, no?)

[fisher26]

It's a real shame what they did with the Oldman Dam. Not only did it affect the flooded river but the crow from the falls down. I have never fished the lower Oldman (the stretch a few miles before it reaches the reservoir), is there the same problem with silt too?