Which type of soil requires examination to confirm it meets the filling criteria in Wisconsin mound systems?

The type of soil that requires examination to ensure it meets the filling criteria in Wisconsin mound systems is organic soil. Organic soils, which are rich in decomposed plant and animal material, can significantly affect the performance and effectiveness of a mound system. These soils often have high water retention capabilities which can lead to drainage issues, as well as reduced soil permeability.

In Wisconsin mound systems, which rely on proper aeration and drainage to function correctly, organic soils need to be assessed to ascertain if they can support the design specifications. The criteria typically involve testing for factors such as depth, texture, and permeability to ensure that the soil can absorb effluent properly. While clay, sandy, and loamy soils each have their characteristics, it is the unique properties of organic soil that necessitate a thorough examination before any filling can occur.