UPDATE 2014-01-15: The attached .zip file now contains a Mathcad Prime 3.0 worksheet (.mcdx) and—for those of you who are still using earlier verisions of Mathcad—an Adobe Acrobat printout (.pdf) of the worksheet so can see how it is put together.
Wetwell pumps require a minimum submergence over the pump intake or suction bell for proper operation. Insufficient submergence can lead to vortexing in the wetwell and the introduction of air into the pump, which, in turn, can lead to reduced pump performance, vibration, and cavitation.
The purpose of this simple worksheet is to estimate the minimum submergence required by evaluating two empirical formulas that are widely used. See Reference  for additional information and constraints. This method assumes a maximum fluid velocity into the intake or suction bell of 5 ft/s.