River Flow Rate?

  • We are currently upgrading MFK. thanks! -neo
Alright Fishman,
So I just focused on the Redbelly Dace. I randomly chose a river system they inhabit. The Pee Dee River. I then used google to search for "pee dee river flow rate" and the first link http://www.blackriveroutdoors.com/More/Rivers/LPD.htm
gives some vital information. More searching will be required to find the width and depth at US501, but I must run to work!
Good luck!
 
I have tried and failed to find the same information. One of these days I'll go out and collect some data of that sort myself. However, in my experience you will not be able to exceed the flow those fish can handle in an ordinary tank; if you get too much current for them, you will actually have water sloshing out of the tank.
 
1 foot per second is less than a mile per hour. If you look at a typical river you will see the water is flowing at least that fast. probably faster. Drop a leaf in and walk beside it.
 
After seeing SNARFERER's approach i found http://pubs.usgs.gov/ds/315/pdf/ds315.pdf (The other link wouldn't open for some reason)

if you were to look at page 3, the measured mean velocity was dependant of the location of measurement, due to the non uniform cross section of the river.

the velocities recorded ranged from 0.4 ft/s to 4 ft/s.

depending on what species, size, etc... different fish would prefer different current flows. (correct me if im wrong) some fish stay near the shore line to prevent swimming against a stronger flow

I realize each river system is very different and depends on amount of rainfall, elevation, grade, etc... so i know there is no "average" value for flow velocity, but what would you (anyone) recommend?
 
How big is the tank?

20x turnover is what I've seen recommended. Something like a quiet one 4000 on one end of the tank, hooked up to a river tank manifold would work good for a medium sized tank.
 
You have to know two things: The area of the flow and the speed of the flow. To get the area you have to measure the depth and width of the river at a particular cross-section perpendicular to the flow direction. Since most rivers have irregular bottoms, you actually have to measure the depth at a number of points across the bed, and draw a cross section. Then calculate the area of the section in square feet.

Then you have to measure the speed of the flow at the same section. This can be done with a flow meter, or by watching something float down the river and timing how long it takes to go a certain distance. The speed is calculated in feet per second.

The total flow is the area times the speed, which will be cubic feet per second. This can be converted to cubic feet per minute, or gallons per minute or cubic meters per minute as desired.

In real rivers, the speed of flow actually varies at different points in the river and at different depths. So to be more accurate, the speed should be measured at a number of places in the same cross-section and averaged.
 
I believe you are trying to hard here as every single river has a different flow volume and velocity and even the same river can have over 300 different flow volumes and velocities through out the year.

Even when the river is flowing on the same day, as you walk along the river you will find velocities differ on a very wide scale from area to area, the flow volume would be the same obviously.

I would just do some trials with different flow rates and velocities to achieve the desired effect.
 
I am a Senior Mechanical Engineering student, so i know a little something about fluid dynamics.

my main question was what would be recomended, so i would be able to design a manifold, pump, and suction to meet the required velocity. I am not certain what size tank yet though.

As i said previously, I am aware that actual flow in rivers change infinitely. I am just looking to mimic a steady flow not to exactly replicate river flow fluctuations.

again i was just wondering what recomended flow velocity i should build to.

thanks for all the input
 
Science aside, besides there being different rivers, there are different fish....A small mouth bass, would not be comfortable in the same rapids a trout enjoys. So I would probably compare the fish you want to keep to a local fish, then go out and ask some fishermen. Or look at fishing reports from the area of the world those fish are from.

On the science side I think you would also have to account for the aquarium being a closed system closer to water traveling thru a tube then flowing down a riverbed.

I have a 350 gph powerhead and it seems to put a pretty good current in my 55 gallon rhom tank. He can swim strait up the jet of water but I can see it is hard for him. Except for in the dead area of the tank (about a 20% area). He must actually swim to stay still.
 
mfgl;3509898; said:
On the science side I think you would also have to account for the aquarium being a closed system closer to water traveling thru a tube then flowing down a riverbed.

I have a 350 gph powerhead and it seems to put a pretty good current in my 55 gallon rhom tank. He can swim strait up the jet of water but I can see it is hard for him. Except for in the dead area of the tank (about a 20% area). He must actually swim to stay still.
Click to expand...

I wanted to build a system whick located the suction at the other end of the tank to "replicate" a current instead of having just the powerhead with its intake located at the base of the head which would create a circular turbulant flow, but this is just my assumption. I would think it would create a whirlpool or eddies.

do you have any idea of the flow velocity your powerhead creates?
 
You must log in or register to reply here.
MonsterFishKeepers.com
Top Bottom