Soil Compaction (Relating to Drainfields)
It is important to avoid compacting the soil in the area of the drainfield site (both proposed site and existing site). Compacting the soils is normally only an issue from vehicular traffic and heavy machinery. This compaction is most pronounced when there is a shallow subsoil or restrictive layer. It is less pronounced with increased soil and installation depth.
Compaction is the process by which soil particles are forced closer together reducing soil porosity. This is caused by heavy machinery traffic and, to a lesser extent, by animals (such as cattle or horses) trampling on wet soils. These impacts include: A reduction in the capacity of water that the soil can hold, an increase in anaerobic subsoil conditions (reducing the amount of oxygen available to organisms), formation of cemented layers or a pan, reduction of root growth and therefore plant development, a loss of soil invertebrates due to the pores becoming too small for them move about and an increase in run-off and flooding.
The rule of thumb is to stay twenty feet (20′) outside the drain field and reserve sites. Remember to never cross a system with a driveway.