???  Does anyone know the formula for figuring the volumn of a slice of a cylinder.  We have a customer that has a wet well with a 6 foot diameter but at the bottom a "wedge" has been added.  The wedge starts 6 inches before the center of the cylinder and extends up 4 feet.  We computer geeks are usually pretty good with math but this one has us stumped and we have been unable to find anything on the net.  

Hmmm,  I don't think it's that simple due to the interaction of the rounded cylinder wall with the upright leg of the "wedge".  I think your best bet is to add water to the empty wetwell until the top of the wedge is submerged.  Keep track of the volume and then the rest is simple geometry for the top portion.  I'm sure there is way to figure it out with calculus but I'm terrible at math.  I'm sure someone here can help.

On thinking about it some more I realized I may have spoken too soon.  Is the "wedge" a chamfer around the entire inside circumference of the wetwell so that if you look directly down at the floor you are left with only a circle of the original flat bottom?  If this is the case than Mr. Taylor's solution will provide an approximation of the volume.  It will be a little off, but probably not much.  However, if the wedge is only in one hemisphere of the wetwell then my original post stands. 


As an alternative to adding water to the wetwell, you might consider pumping the water level down instead.  You can calculate the pumping rate while the water level is above the top of the wedge and use this rate to come pretty close to figuring the whole volume.  There will be some change in the pumping rate the further down you pull the water level but it will likely be a very small change.  

Even if you come up with an equation describing the wedge that you can integrate using calculus it will still be an approximation.  If your volume has to be right on the money than you either have to use the actual wetwell or make a scale model.  A scale model would be pretty easy by using a beaker or even a bell jar.

Thanks for the ideas.  They worked great!  Now for the fun part... telling the customer that his controls are working fine, the problem is the active volumn of his wet well is 4 times too small for his inflow .