How much water is this?

Otisd85

New Member
Joined
Jan 2, 2020
Messages
24
I have a pond and I'm trying to figure out how to determine how much water is coming out of the overflow culvert. It runs like this year round, and I'm thinking about a low head unit from Langston Alternative, but I'm not sure how to figure out if the pond will support a 6" siphon.org_60e222d085039d09_1584302904000.jpgScreenshot_20210122-162936_Gallery.jpg
org_e78702116b52f170_1582393016000.jpg
 

Otisd85

New Member
Joined
Jan 2, 2020
Messages
24
I appreciate the suggestion, but I think it's too much water for a bucket test. The stream coming out of the culvert is wider than a bucket, and I'm pretty sure it would fill the bucket instantly. I doubt I could hold on to the bucket and don't think I could time it accurately. Also, I'd have to do it from a boat.
 

Otisd85

New Member
Joined
Jan 2, 2020
Messages
24
A 55 gallon drum may be more feasible. I'll have to see if I can float it out there and try to time how long it takes to fill and sink.
 

Hedges

I See Electromagnetic Fields!
Joined
Mar 28, 2020
Messages
8,351
1611364235263.png

Just float it, and slip it under the waterfall. Use a stopwatch.

The Lift Guy's suggestion should work too. Float a drum up to it, shove against pipe. Before it overflows, pull off to one side and measure depth.
 

Hedges

I See Electromagnetic Fields!
Joined
Mar 28, 2020
Messages
8,351
I suggest routing the 6" pipe to four nozzles on the turbine, 2 always on and the other two controlled by an electric valve and float switch in the pond. It should get 100% for a wider range of flow that way.

Oh, sorry. I'm thinking of a Pelton wheel. Their low head unit doesn't look like you can run with varied flow that way.
 

Darkstar

Rain Wrangler
Joined
Dec 31, 2019
Messages
327
That pipe is a circular weir. Use a circular weir formula or online calculator.




I have a pond and I'm trying to figure out how to determine how much water is coming out of the overflow culvert. It runs like this year round, and I'm thinking about a low head unit from Langston Alternative, but I'm not sure how to figure out if the pond will support a 6" siphon.View attachment 34192View attachment 34191
View attachment 34188
 

Maast

Compulsive Tinkerer
Joined
Oct 31, 2019
Messages
770
Location
Washington State
You'll need to set up a "V notch weir" and measure high up it goes, then you can accurately calculate how much water is going through.
 

Otisd85

New Member
Joined
Jan 2, 2020
Messages
24
I suggest routing the 6" pipe to four nozzles on the turbine, 2 always on and the other two controlled by an electric valve and float switch in the pond. It should get 100% for a wider range of flow that way.
I don't think i have enough head for that type of setup. It's only about 10' from the surface of the top pond to the surface of the lower pond.
 

Otisd85

New Member
Joined
Jan 2, 2020
Messages
24
I've come across info about v notch weirs but that's the first I've seen of a circular weir, I'll have to look into that more. I wasn't confident in doing the math for a weir, but if I can get a base estimate with a bucket test using a 55 gallon drum and it seems like it's going to be enough water, I think I'll build a weir to double check my work and compare my numbers between my two tests.

Thank you to everyone for the suggestions.
 

Darkstar

Rain Wrangler
Joined
Dec 31, 2019
Messages
327
You would want to measure the water on the pond side or intake side of the pipe if you use the weir method...
 

Otisd85

New Member
Joined
Jan 2, 2020
Messages
24
You would want to measure the water on the pond side or intake side of the pipe if you use the weir method...
You don't think a v notch weir would be accurate on the end of the culvert?
I know nothing about weirs, that's why I'm asking. It's the same water going in as it is going out, isn't it? If I built a weir on the top side, I'll have to raise the water level by the amount the weir comes up.
 
Last edited:

schmism

Solar Addict
Joined
Jul 13, 2020
Messages
1,011
Location
Central IL, USA
weirs work, however you have to know how to install them and do the math for them Which is why the bucket test is typically the fall back for "small" flow rates.
 
Top