University of Illinois Extension

Quiz

Practice Problems: Sizing Residential Subsurface Seepage Systems 3

Sizing of subsurface seepage systems is done by applying the soil loading rate to the average daily flow, or the number of bedrooms for residential settings.

The soil loading rate can be calculated by using either a percolation (perc) test or a soil evaluation.  The procedure for conducting percolation tests is found in section 905, Appendix A, Illustration G of the administrative code.

Information on using soil evaluations and loading rates is found in Section 905, Appendix A, Illustration M

Information on calculations for gravel trenches is found in Appendix A, Illustration H, Exhibit A.  Exhibit B is used for gravelless pipe.

Residential Practice problems.

A 3 bedroom house has a perc rate of 180 minutes.
  1. Practice Problems: Sizing Residential Subsurface Seepage Systems 3

    How many linear feet of 24 inch gravel trench would be required?

    435 feet
  2. Practice Problems: Sizing Residential Subsurface Seepage Systems 3

    How many linear feet of 36 inch gravel trench would be required?

    290 feet
  3. Practice Problems: Sizing Residential Subsurface Seepage Systems 3

    How many linear feet of 22 inch chamber would be required?

    217.5 feet
  4. Practice Problems: Sizing Residential Subsurface Seepage Systems 3

    How many feet of 10 inch gravelless pipe would be required?

    300 feet