Hydro electric power is the most reliable and cost effective small-scale renewable energy source available. A small hydro system utilizes a turbine, alternator, water jets aimed at the turbine and a control circuit. Other required components are a battery storage bank, regulator and enough water line to get the water to the turbine. Hydro systems, unlike solar components, do require some maintenance. To take advantage of hydro power your water source must provide both volume and pressure (otherwise known as head). If your creek or stream can deliver more than 5 gallons per minute then you have enough flow volume. Pressure, or head, is the height the water falls vertically. A standard microhydro system needs at least 10 feet of head in order to provide usable amounts of power.
To determine the power that can be produced at your site you need to know the flow and head. Flow (the rate at which the water moves in the stream) is measured in gallons per minute (gpm) or liters per second (lps). You can determine this by channeling water into a pipe and then into a container with a known volume and then noting the time it takes to fill the container. The head, which is the vertical distance the water travels, can be measured either by using a transit or by siting along a level. This can also be done by using a transparent hose and using it as a level or by utilizing a length of pipe filled with water with a pressure gauge attached to the end. Once the head and flow are known the appoximate power output can be calculated with the following formula: Head (feet) X Flow(gpm) / 10 = power output (watts)
(Note: the accuracy of the output calculation depends on the accuracy of your measurements.)