The other important measurement to take when assessing your creek for microhydro is pressure or head.  The two terms are different measurements of the same thing --- potential energy just waiting to turn your turbine and make some power.

Many homesteaders pipe water from a spring down to their house, and the energy in the water line can be tapped for microhydro power.  To measure pressure directly in such a situation, install a gressure gauge in the line and read the dial.

If you don't already have a water line in place, you're better off calculating a stream's head rather than measuring pressure directly.  Head is simply the change in elevation between the highest and lowest points of a stream, and it can be measured in several different ways.  If you have a gps or watch with an altimeter, this can give a rough measurement of the respective elevations, but I found the water level method (outlined in the embedded video) to be the simplest.

To measure head using the water level method, find an inflexible length of pipe and start at the stream's highest point.  Completely submerge the pipe, then slowly lift the downhill end out of the water.  Creek water will flow out of the pipe's downhill end until it is raised level with the uphill end, at which point water will stop flowing.  Measure the vertical distance between the downhill end of the pipe and the ground and you have the change in elevation between the two points.  Now scoot the pipe downstream until the uphill end rests where the downhill end used to be, and repeat your measurement.  Lather, rinse, and repeat until you run out of shampoo...er, reach the end of the stream.  The head is the sum of all of the elevations measured along the creek's length.

The downfall of our property's creeks is their valley-bottom flatness.  Our small creek has the largest head, and even there the total change in elevation is barely over three feet.  Granted, microhydro applications can work with as little as 2 feet of head, but the setup becomes much pricier if your head is less than 50 feet.

This post is part of our Microhydro lunchtime series.  Read all of the entries: Microhydro: Clean Power From Water Cutting your electric bill by 90% Microhydro assessment: Measuring flow Microhydro assessment: Measuring head Microhydro assessment: Estimating power

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About us: Anna Hess and Mark Hamilton spent over a decade living self-sufficiently in the mountains of Virginia before moving north to start over from scratch in the foothills of Ohio. They've experimented with permaculture, no-till gardening, trailersteading, home-based microbusinesses and much more, writing about their adventures in both blogs and books.



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