Does anyone have an idea of how much a bar guard restricts water flow? I have a 24" Agri-drain heavy duty bar guard which has a total of 16 bars spaced a little over 3" apart. I haven't measured the bar widths but they look like 3/8". So do you just add the width of those up and then subtract it from the total pipe diameter? If so, this would reduce the flow of my pipe down from a 24" to an 18".... I just replaced a 15" overflow pipe with this 24" pipe and added about 4-5 feet of headboard on the dam b/c I had the dam topped this spring. I hate to reduce the 24" pipe to an 18" with the bar guard. But..If that is the case, would it be better to build something 4-5 feet out in front of the pipe so as not to restrict the total flow?