Wisconsin Mound Soil Absorption System and Area FillPractice Exam

Wisconsin mounds can be designed on sites where the seasonal high water table must be at which minimum depth from the soil surface?

1. 5 inches

2. 10 inches

3. 12 inches

4. 15 inches

The correct answer is: 10 inches

In the context of designing Wisconsin mounds, it's crucial to consider the seasonal high water table because it can significantly impact the functionality and effectiveness of the soil absorption system. The minimum depth of 10 inches from the soil surface to the seasonal high water table is relevant because it ensures that there is adequate drainage for the mound system to operate effectively. When the water table is too close to the surface, it can saturate the soil around the absorption area, leading to insufficient aeration and posing risks of failure or inefficiency in wastewater treatment. A 10-inch depth helps to maintain a buffer zone between the water table and the mound, allowing for optimal organism activity and nutrient processing within the soil. This depth, therefore, is a crucial design parameter to ensure that the system can adequately treat wastewater before it reaches the groundwater. Other options reflecting smaller depths could compromise the system's performance due to potential saturation, leading to leaching of untreated effluent into the groundwater, which is why those do not represent suitable minimum requirements. Furthermore, deeper depths could be unnecessarily restrictive and may not be feasible for all site conditions.