More on how to use these books (pardon the premature submission)
Serious Microhydro: Water Power Solutions from the Experts is an anthology of articles, mostly from Home Power Magazine, that include over 70 microhydro systems. Every site is unique, especially with microhydro, and so no one site is "typical". Thus, having a collection of sites from which to choose is the best way to proceed. There is a chart in the beginning that compares the characteristics of all the case studies, arranged by head. After you find out just how much head your potential site might have, then you can find an article about a system with similar characteristics. There's a range of heads from 22 inches to 746 feet, and flow rates from 5-10 gallons per minute up to thousands of gallons per minute. Most likely, you'll find something like your site there.
There's an article, reprinted from Microhydro: Clean Power from Water, that shows a person (for scale) and various flows of water. To estimate your water flow, compare it to these photos. More water than that? You've got lots!
There are articles about the general context of energy. You need to have a realistic notion of your needs in order to get a right sized system. For example, there's a case study from California of a household photovoltaic system that doesn't cover the whole roof of the house, but still runs both house and electric car. Enough energy falls on your roof (never mind a powerful microhydro system) to power your house and car. That's important news for people to know. Now I hear that there's a bakery in Esquimalt BC that does the same, so its not just for California.
There's also an opportunity to think about the future, with articles on net metering and a proposal for microfinance for microhydro.