Determining The Height Of A Waterfall

© 1999 by Scott A. Ensminger

     In my research on waterfalls often the most confusing aspect has been in determining the true height of a waterfall. A review of available information on a particular waterfall often reviled two or more heights. Sometimes these heights differed as much as 20 feet (6m) or even more.

     It was a TV show on forestry, in which they showed to measure the height of a tree, that lead me to a way of accurately measuring the height of a waterfall. In the show a clinometer, an instrument used to accurately measure angles, was used to find the angle to the top of the tree. A measurement to the base of the tree was then taken using a tape measure. Then by using trigonometry the height of the tree was determined.


     But after using this method to determine the height of a few waterfalls, I realized it had a few flaws. Most waterfalls do not have a 100% vertical plunge, and obtaining the distance measurement was sometimes hard, if not dangerous. After consulting a book on trigonometry I began using the following method to determine the height of a waterfall.


     In using this method the observer must stand at a point that is level with the plunge pool, which is level with the base of the waterfall. The observer then determines the angle of elevation and distance to the crest. I use a Suunto clinometer to determine the angle. To determine the distance to the crest I use an coincidence rangefinder, an optical device that produces two images of the object that is being viewed. When the images of the object are focused into a single image the distance to the object is indicated. I also use a laser range finder to determine the distance to the crest.

     But it was not always possible to easily get to the base of a waterfall. So I began to use the following method to determine the height of a waterfall from the crest. Using this method the observer must stand at a point that is even with the crest of the waterfall and determine the angle of depression and the distance to the plunge pool.


     In determining the height of a waterfall I usually try to take a couple of readings from below the waterfall and a couple of readings from the crest of the waterfall. I then add the results of these readings together and the divide by the total number of readings. I then use this result for the height of the waterfall.

Return To The Home Page Of WNYWS

This page hosted by GeoCities Get your own Free Home Page.

1