Reuse Of Reclaimed Wastewater Through Irrigation

Bulletin 860

Step 2

a) Determine the limiting soil infiltration rate for the proposed site. County soil surveys published by the Natural Resources Conservation Service (NRCS) report soil permeabilities in inches per hour for the top 60 inches of the soil profile.

b) For the proposed irrigation site identify the lowest soil permeability within the top 60 inches.

c) Convert the soil permeability in inches per hour to soil infiltration in inches per month. From 4 to 6 percent of the permeability is reflected in the infiltration rate of most soils. This factor is up to 10 percent for highly permeable soils.

Example

The soil survey indicates that the lowest percolation rate in the top 60 inches of soil in the neighboring crop field is 0.2 inches/hour. Therefore, the corresponding soil infiltration rate is 6 inches/month.