What to do when water is moving 500 cfs plus?

[dougm]

Does anyone has any pointers on fishing a river where the current is right around 500-550 cfs? Can trout navigate current this strong behind rocks, logs,etc? or do they simply move further downstream to the deeper pools?
Also, when casting in these conditions....once my floating line hits the water, the current makes it hard to "mend" and make corrections fast enough over the areas that I suspect may even hold fish....if there are any. The water is clear but just moving fast....and it's probably going to stay this way because the big lake upstream got a lot of rain water from the past few months and the Army Core of Engineers has to make several releases...thus keeping the water movement around 500s cfs. Any pointers would be great here for a new guy to freshwater current!

Thanks, R. Logan

 

[DAVY WOTTON]

FAST WATER

Mr Logan,
Good question posted.
I do not have the space here to write a real detailed answer but to summarise for you.
Fish can deal with amazing forces of water, they live in it. I have seen salmon negotiate falls that defies the law of physics.
First the surface of the water moves at a speed a great deal faster than at the bed of the river. Fish know how to find current seams that allow them with min expelled energy to stay in a comfort zone. 500 cfs is not that fast, here on the White with all units open it is something like 24,000 cfs. But you can go and catch fish in it. I have fished some rivers that move a great deal faster than that.
Yes, you will find fish around structure that form breaks in the downstream force of water, and they are always good zones to fish.
But your problem is of course being able to control you fly line.

I can give you many answers here so far as fishing techniques that you could use. The bottom line is this. I assume you were nymph fishing.
First you have to able to get the fly down to the fishes zone and that would reguire some addition of weight to your fly or leader or both.
Then you have to consider-- how long can my fly remain in a productive drift zone--that is achieved by allowing sufficient slack line and controlled mends to achive that.
There is a technique called high stick. in extream cases it may be termed as chuck and duck, when a great deal of weight is used. that may be incorporated with one or more flies and the additon of weight to the leader or both.
You are essentially using weight that will allow for the fly to sink real fast, from that point on the rod is held high and you follow the track of the fly for a short distance. You generally do not cast a length of fly line.You use maybe a rod length or less for a short track of the fly in the zone you expect to find fish. It can be very deadly l can tell you.

You can use a indicator or watch the flyline/leader for a hit, I choose not to use a indicator, but l have practised this technique for many years.
It is a perfect method to fish short deep pocket water situations and one when you have problems trying to deal with very fast flow rates. That do not allow for effective long range drifts.

One other tip l will give you is look for zones that have a slower rate of flow and also back water eddy's. many fish can congregate in these places.
With practice you will be able to read water movement and that can tell you a great deal so far as the likely places you will find fish.

Hope this helps you some

 

[Cliff Hilbert]

Heck Davy, I've been fishing for trout for about five years now and THAT HELPS ME! Thanks for a very good answer.

 

[Gordon Bryson]

When addressing the discharge of a stream, most of the reporting sites do in fact gage the discharge in cfs (cubic feet per second). This is the quantity of discharge going through the controlling gates, weirs, or generating turbines. The swiftness of the water, current, depends then on the configuration of the stream bed, i.e., how wide, how deep, etc. A stream bed of 100 feet width and a depth of one foot with a discharge of 500 cubic feet per second would have a current moving at approximately 5 feet per second (about 3.5 miles per hour). Again, with a discharge of 500 cft, assume then the stream bed width is 50 feet wide and only one foot deep, then the water will be traveling at twice that current speed, or 10 feet per second (about 7 mph). There are many conditions downstream of the discharge control point that will affect the current speed, this example is only meant to help one understand the difference in discharge (cfs) and current speed (fps).

This would mean one should know something about the particular stream and what the conditions are at 100 cfs, 500 cfs, and so on. In other words, a discharge of 500 cfs at Lower Mountain Fork might result in a current much less than 100 cfs at another stream. I hope I haven't made this too confusing. The point is, you must know what affect on current the different discharge amounts have on each stream.

 

[DAVY WOTTON]

FLOW RATES

Gordon,

Thanks for that post, good one.

Question.. By what mathmatical equasion is this factor calculated , Gordon.
This kind of thing interests me.

Thanks Davy.

 

[Gordon Bryson]

Davy, I'm going to have to look up some info to give you a better answer. Some 50 years ago I worked part time for the Texas Board of Water Engineers and U.S. Geological Survey, Surface Water Division. We did a lot of stream measurements, and as I recall we took average water velocity (water depth 4 feet, velocity taken at 2 foot depth) and this was averaged for the width of the stream. In other words, you essentially took a profile of the stream bed to calculate the cross sectional area which would be in square feet. Then using an average velocity, in feet per second, the discharge volume is a product of the area in square feet multiplied by the velocity in feet per second, and the number is quantified in cubic feet per second, cfs. Then taking this even further, stream reporting came in as the gage height at a particular point in the stream. Further refinements would establish a permanent gage mark on a particular stream, and with a set water level a known discharge was calculated. Then, with fluctuations in the water level the changes in discharge volumes would be known. The government does an awful lot of measuring and recording that sounds to be superfluous, but in overall watershed management becomes pretty important.

If I can shed anything further, just let me know.

 

[Gordon Bryson]

Davy, one other thing. As you travel around and cross a stream bridge, look to see if there is a round metal structure beside the bridge. They look like a silo, and now most of them have a solar charging panel on them that powers the measuring equipment inside. They may even have it set up that there is a transmitter that sends the stream data via a satellite to the recording and controlling agency. We used to get a chart out of them that recorded stream level over a period of time. I'm sure the technology is pretty advanced now. Just a little trivia that you can use to show someone you know what those things are for. LOL

 

[DAVY WOTTON]

Flow rates.

Thanks, Gordon.
Yes, l know a number of places that they have gauges at certain points for that.
I am often asked by the clients How fast is that water moving, MPH, and as you rightly stated that changes as you move down the river.
I used to know a simple formula for that and l have for got how to do It, l do not know how accurate it was, but it amounted to something like counting in seconds, for a given distance a floating object.
Say it took 10 seconds for the object to travel 20 yards. You may well know the answer to that one or a alternative way to calculate it. If not, no problem.

I think that a USA mile may be different from UK, 1760 yards. I know that gallons are.
Sorry to get you going here but you got my brain in gear with this one
I can catch fish ok, but l am no mathmatical genius !!!

Thanks again Davy

 

[Gordon Bryson]

Davy, if you're comfortable with a distance of 20 yards ( 60 feet) then you could get a pretty close approximation of speed in mph by dividing the number of seconds it takes for an object to float the 20 yards into 40. (It actually works out to 40.8, but we're not doing rocketry science here). Assuming your 10 seconds to float the 20 yards, the water would be flowing about 4 miles per hour. (40 divided by 10 = 4).

There's an article on river currents and its effect on divers, etc at this website. They also have a table in there giving currents in mph based on the time it takes an object to float 100 feet.

http://www.oseh.umich.edu/CurNav.pdf

Happy Floats! LOL

 

[DAVY WOTTON]

flow rates

Thanks Gordon,
I had every confidence in you for the answer.
That was about it, that l had forgot. knew it was something reasonably easy to figure out.

Will check that site also, in fact scuba diving is one of my pastimes. like to see them big Browns face to face here on the White !!

Davy.

 

[Curtis]

A few years back here in Utah on the Green river we had flows of up to 10,000 c.f.s. Now, our normal summer flow is 800-1000 cfs so this was HUGE! I had the best fishing I have ever had on that river during that high water. The fish, including the pigs that wallow in the deepest water that is all but unreachable were pushed to the outer edges. I was catching fish that were actively feeding on the foot trails I had hiked the summer before. So, check the edges. Dont wade in right away when the water is high but cast first to the edge areas.

 

[Fish Bones]

Hello Curtis:

Thanks for you post. Good information. Welcome to the foum.

Steve

 

[DAVY WOTTON]

High Water

Same here also on the White, during the high water, you will find many fish way back over flooded ground and way up in small feeder creeks.

They are feeding on acorns in the trees and corn in the fields.


Davy In reply to Curtis.