Water power from pathway runoff?

I have a nice clear area on my very steep, hilly, rocky piece of land that I want to use as a driveway. It is clear and flat because it is a springtime water runoff/almost a stream bed. I do not want to pave or buy TONS of gravel to make it useable. The other areas of the lot may be even more difficult to use for a driveway, but we need something. I am thinking of putting in a french drain through the middle of the "driveway" with a pond or something at the end of the drain. Would this sort of set up allow for some sort of energy collecting unit? Does the water need to be flowing all the time to make it functional at all? We are totally off-grid so even a little power might be worth it. Any thoughts? I posted a little more in depth on my blog:
http://nepermhome.wordpress.com/2014/07/16/driveway-stream-to-french-drain/

It turns out, there's a convenient little formula to determine how much energy you could potentially extract from falling water:

Power = (Head ) x (water Flow) x (Efficiency) / 11.8

Power The electric power in kilowatts (one kilowatt equals 1,000 watts).

Head The distance the water falls measured in feet.

Water Flow The amount of water flowing in the river measured in cubic feet per second.

Efficiency How well the turbine and generator convert the power of falling water into electric power. For tiny inefficient turbines, this could be as low as 10 or 15%, while for newer, giant, well operated plants this might be as high as 90% (0.90).

11.8 Converts units of feet and seconds into kilowatts.


A google search for how much energy in falling water will get you a scad of resources on how to evaluate your particular water site.


Yes, the water has to be moving to be able to extract useful energy.


Hope that helps!


troy

It does help. I'll have to do some investigating!