Wisconsin Mound Soil Absorption System and Area FillPractice Exam

For fill material, what characteristic is essential for the sand being used in mound systems?

1. Highly compacted

2. Low permeability

3. Coarse texture

4. High moisture retention

The correct answer is: Coarse texture

The characteristic that is essential for the sand used in mound systems is its coarse texture. Coarse-textured sand allows for proper drainage and prevents water from pooling in the system. This permeability is crucial because mound systems rely on the movement of effluent through the sand bed to facilitate treatment via aerobic processes. Fine-textured materials may retain too much moisture, leading to saturated conditions that can impair the performance of the mound system and increase the risk of system failure. Maintaining an optimal balance in the physical properties of the fill material ensures that the effluent is adequately distributed and treated effectively as it moves through the sand layers. Therefore, selecting sand with a coarse texture is vital for achieving the desired soil absorption capabilities in a mound system.