In Scenario II, what soil condition is assumed to allow for a soakaway?

In Scenario II, what soil condition is assumed to allow for a soakaway?

• A. Dense clay
• B. Porous and unsaturated soils
• C. Waterlogged
• D. Rocky bedrock

Answer: (B)

A soakaway relies on water moving downward through the soil and dispersing into the surrounding earth. For that to happen, the soil must be able to transmit water quickly (high permeability) and not already be fully saturated with groundwater. Porous soils provide the gap in the pores for water to move through, and unsaturated conditions mean there’s air in the pores to allow continued drainage by gravity. If the soil were dense clay, infiltration would be slow and water would tend to pond at the surface. If it were waterlogged, there’s little or no air in the pores, so drainage is severely limited. Rocky bedrock offers almost no soil for infiltration. Hence, the assumed condition is porous and unsaturated soils, which enable the soakaway to accept and drain effluent effectively.

A soakaway relies on water moving downward through the soil and dispersing into the surrounding earth. For that to happen, the soil must be able to transmit water quickly (high permeability) and not already be fully saturated with groundwater. Porous soils provide the gap in the pores for water to move through, and unsaturated conditions mean there’s air in the pores to allow continued drainage by gravity. If the soil were dense clay, infiltration would be slow and water would tend to pond at the surface. If it were waterlogged, there’s little or no air in the pores, so drainage is severely limited. Rocky bedrock offers almost no soil for infiltration. Hence, the assumed condition is porous and unsaturated soils, which enable the soakaway to accept and drain effluent effectively.