# How to make sure a pipe does not take all of the water from a stream?

I am trying to design a pipe which takes water from a river and transports it to a reservoir.

However, I do not want my pipe to take all of the water from stream, because that will create all sorts of environmental problems.

How do I make sure that this does not happen?

The flow rate in the stream is $$0.02 m^{3}/s$$ and the stream is $$1m$$ wide and $$1.25m$$ deep.

Do I just need to make sure that the flow rate in my pipe is not greater than $$0.02 m^{3}/s$$?

• Are your numbers correct? The "stream" would only have a flow speed of about 1 meter per minute which doesn't seem right. And at 1 cubic meter per minute it will take a very long time to fill a typical sized reservoir. Nov 3 '18 at 19:59
• @alephzero This is only a theoretical example, but the reservoir will be for a small-scale hydropower plant, producing about 100W. Nov 3 '18 at 20:04
• Use a small diameter pipe... Nov 3 '18 at 21:43
• You build a diversion sluice that has an entrance that is higher that the steam bottom. See here Nov 4 '18 at 13:38