There is an easy math formula to help determine infiltration, which an operator needs to be able to determine on those rainy days so adjustments can be made.
Percent inflow and infiltration = actual flow x 100
The average flow to your facility is 2.75 MGD. When you receive ½ inch of rain, your flow increases to 6.9 MGD. What is the percentage of inflow and infiltration?
The percent inflow and infiltration rate can be derived directly from the formula.
Once we know our actual and average flows, we just plug them into the formula then multiple by 100 to turn it into a percent.
Percent inflow and infiltration = 6.9 MGD x 100 = 250%
Check out the Test Your Knowledge – Finding the Percentage of Inflow and Infiltration post for an additional practice problem.