Simple Weirs and Orifices, on video, and in photos!

Simple to set up weirs and orifices!

On YouTube:  https://youtu.be/H2tOEV-zitk

This is a corner of a diversion box built by my wife’s grandfather, Emil Wigno, in 1922.  The fleur de lis he brought with him from France.  🙂   Emil planted hay, peaches, prunes, and finally walnuts.

Hi, I’m Shawn Pike.  🙂

Now 2″ x 6″ boards, cut 1/2″ to 1″ shorter than the width of the board slots, are stacked up in the diversion box.

The weir board is cut 3-1/2″ deep.  There are 2 weirs, one 1.0′ wide, and the other 0.5′ wide.  These are contracted weirs, since water on the edge has to turn to go through.

The small weir is blocked off, so the 1.0′ weir is left.  This is a 1.0′ contracted weir, and the flow can be read right out of the correct table in the Water Measurement Manual.

By simply flipping the weir board upside down, we have an orifice!  If the downstream water is higher than the hole, then the orifice is “submerged”.  If the flow out the orifice is free-flowing, then a different equation is used.  Either way, calculating the flow is pretty easy because we know the orifice area, and depths of water upstream and downstream.

Here’s the pretty photographer and videographer, in the gold-mining town of Bodie.  🙂