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Binaya gravatar image

Potential power output from a river.

I am posting this question on behalf of David Lloyd-Jones, a thermal engineer in UK.

While in Kenya i was asked to estimate potential power output from a river. We have around 80mtr head but the water flow/volume is throwing me. I found a flat weir upstream with a flat pond behind and measured 30cm depth across 2.6 width - ie .78M2.(ie 780 Litre) My logic tells that the flow rate must be pretty close to 780 litres'sec. The only advice i can find online, tells me to measure cross sectional area x flow rate as measured with say a floating tennis ball covering 10mtrs in say 10 seconds. 1/ I didnt take this measurement and am now back in UK 2/ I can understand the need for a flow rate on a sloping water body (ie river) BUT when you have a flat body (pond) with a flat topped weir then the M2 over weir MUST correlate with volume/flow rate yes??? - PS i dont need to dead accurate - plus/minus 20% would be good enough. If 780 L'sec then x say 80mtr head and lets say i only take 20% of river x 60% to allow for losses will give around 110kw?? (+-20%) And i think around a 10 or 12" steel penstock pipe Am i anywhere near with the above numbers??