Monday September 19, 2011
What’s brewing in the FABLAB? Nothing that’s going to revolutionize the world as we know it, but definitely something that will come in handy for our projects this fall. As you may know, sometimes it’s necessary for us to fabricate equipment in our shop facilities. In this case we are making a devise called a piezometer, which is commonly used to measure the flow of water through gravel in a streambed. A piezometer basically consists of a permeable standpipe with a hose attached to a vacuum pump. The pipe is driven in to the desired depth of the streambed, and the hose is used for drawing water out of the center of the probe. In fisheries, a piezometer is often used to measure flow and dissolved oxygen in spawning gravel. Intragravel flow can be determined by drawing a known volume of water under constant vacuum pressure for a given amount of time, as demonstrated in this YouTube video. Since gravel size, composition, permeability, and dissolved oxygen are substrate parameters affecting the survival of incubating salmonid embryos, a piezometer gives biologists the opportunity to measure these parameters directly, at specific locations without disturbing the sample site.