What is the final step in determining the perc rate?

The final step in determining the perc rate involves measuring the time it takes for the water level to drop from 9 inches to 6 inches, and then dividing that time by 3. This method is used because it helps standardize the perc rate based on a specific volume of water and provides a more accurate representation of how quickly water can percolate through the soil over a defined vertical distance.

Measuring the drop from 9 inches to 6 inches allows for a focused observation of the rate of percolation over a shorter interval, which is often more effective than measuring larger drops. Dividing by 3 is a crucial part of the process, as it correlates the observed percolation rate to a standardized measure of permeability, enabling comparisons to be more easily made across different soil types and conditions.