River Flow Change...High to low...

[Drag Free Drift]

When flows change from high to low (1,500 cfs to 300 cfs) is the fishing usually good right after the change? Or do the fish take time to adjust to the change of flow? What other conditions may effect the fishing after flows change? Water Clarity? Debris in the water? Thanks in advanced.

[Bill Kiene semi-retired]

These are just ideas......


I think it takes longer for the fish to stabilize after the flow goes up.

In the late Summer and Fall when it rains the fish can turn on.

When the flow goes up migratory fish usually move up river.


Having the water go up and down dramatically every day can't be good for the ecosystem.

Many years ago we had an aquatic insect class on the South Fork of the America river at Lotus.

Mike and Kristine Fong put on the class for my shop and the flows then use to go up and down daily.

Mike turned over many rocks during the low flow stage and we did not see hardly any insect life.

[JasonB]

Good questions. I’m certainly no expert, but I have had a lot of my fly fishing experiences on a river that does just that. Unfortunately. I’ve heard conflicting opinions on water flow changes, in terms of best and worst times to fish, but overall it does seem to hold true most of the time that fishing right around a sudden rise or fall in flows tends to shut the bite down for resident trout. For me, that has been noticeably moreso in the case of dropping flows, but I would hardly say that I’m fully convinced that would always be the case. I have experienced very good fishing a few times right as flows start to come up, presumably because it’s stirring things up and dislodging various menu items for bigger trout, but again this may well be somewhat situational.

Other issues you mention would also be potential factors, but can be addressed to some degree by what kinds of flies you fish, where, and how you fish them.
JB

[Rich Morrison]

Here’s what I’ve seen...
Temp change makes a huge difference. So it depends a lot on where the water temp was before the flow change and what is causing the flow change - does it change the temperature of the water? Fish are far more sensitive to temperature than they are flows. If the temps are good for feeding trout (generally the best temps are in the 45- 60 range) and the flow change does not change the temperature much the trout will feed. If this is the case usually an increase in flows can stir up the substrate a bit and put a little more food into the water column and that can improve the fishing. Drops in flow that are large usually reduce the bite for a bit. My opinion is that when that happens the fish have to re-set the feeding lies and the pecking order before they settle down again and start feeding. But again, temp is the biggest factor. If the rise is huge due to heavy rain upstream it’s best to back off and make sure things don’t get unsafe because that can happen in a hurry. Always a good idea to be cognizant of the lay of the land and the weather so you don’t end up drowning.

[Andy]

Hijack

The Klamath went from low ~1500 to 6000 last night. They plan and post this event. Idea is to roll the rocks and kill the worm colonies that cause the smolt killing c shasta disease. Cool to see her rip like a real river once in a while. Will go back down over a week tapering into the Salmon Fly event. Go Klamath!

Andy