...Define micro hydro?...lol
The stream/creek in your back yard could definately apply!
That is what I love about this forum....everyone here shares a basic interest-trying something different than the "jones's". I think everyone in here has a healthy quest for knowledge...and sharing of ideas.
...A few things to consider before you "develeop" your idea. First, do your local and state laws allow you to mess with that stream? I've thought the same idea you are thinking...unfortunately in this day and age you would probably be at odds with some governmental institution. If you damn up the stream....is anyone likely to complain from downstream?
...Water power is like Coal...it's old technology, but has potential. Many a New England factory,shop or mill have been powered by water over the years. The questions you have to ask yourself are: How much time, how much money am I going to invest...and what is the return?? If you are looking for a financial return...it will never happen. If you are looking for the return of "I set out to do it and it worked" then it might be priceless!
In other words...Is this a hobby with a slight payback? If so start with a water wheel, hooked up to a small alternator, and a few batteries.
...All depends on what you want to do with it.
....Have you ever heard the term "Pumped Storage?" This one amazes me! Out in Western Massachusetts, New England Power pumps river water at night to the top of a mountain (off peak-short money) when there is "extra power" for sale...and then during the day when demand for electricity is high (and someone is willing to pay good money), they let last nights water back down the mountain, turning the pumps into generators! And get this...they actually turn a profit doing it! Go figure it's a big battery for a coal plant when you think of it!...lol
...If you want solid energy alternatives...look into PV (photo voltaic). I know people here in town that get a check for $150/month from the light company..go figure!