One improvement I want to make is placing a piece of metal in front of the board and up an inch or so from the level of the notch. This will make a thinner area for the water to flow over which gives a more accurate measurement.
There are still some leaks from the bottom of the weir, running about 25gpm (a conservative guess on my part).
Following are some estimates of streamflow using this method, with an estimated accuracy of +/- 30gpm:
Assuming irrigation rates of 96-146gpm, I will be leaving a downstream flow of 165-215gpm flow (using September 4th measurements).
DISCHARGE FROM A RECTANGULAR WEIR WITH A FOUR-FOOT WIDE CREST GIVEN IN US GALLONS PER MINUTE
|Gauge Reading in Inches||GPM|