This is something I am also very interested in.
We have constant trickle of spring water on the hillside where we live. (low volume) but we have 50m of head to get the pressure up.
My idea ...
to collect various sources of water - roof /spring/ land drains into a holding tank ... 1000 litre IBC (cube) tanks are freely available
look up Intermediate bulk container - Wikipedia
.. and it would be possible to "daisy chain" them if capacity was required.
The original poster talked of opening a valve to start it all off... however I think this is may not be necessary. A simple Bell Siphon could automate this
Rainwater starts to fill the holding tank(drum).
Siphon hits tipping point near full tank and starts to flood generator pipe.
Drives Generator until holding tank is depleted - up to the point where the siphon is broken.
If rain continues to fall the tank will fill again and the cycle will begin again automatically.
So the generator will cycle ... it doesn't sound ideal but in a situation where there isn't a huge volume of water it could be used to charge batteries.
Also in the situation where a direct connect system falls below the required flow to drive the generator - not enough torque - this would build up enough of a buffer to mean the water is not wasted by just trickling past the generator...
Hopefully what I have written is understandable!
I would be interested to know if anyone has tried something similar...
or if it is just a dumb idea
