Can Mound Systems Handle Heavy Rainfall Without Overflow?

Designing for Heavy Rainfall

A well-designed mound system incorporates a drainfield, a treatment area, and a soil composition that can handle excess water. This is achieved by excavating the drainfield to a depth that allows water to infiltrate the soil, rather than flowing across the surface. For example, a 10x20 foot drainfield, excavated to a depth of 4 feet and separated by a 1-foot berm, can handle approximately 500 gallons of water per day.

Maintenance and Regular Inspections

Regular maintenance and inspections are essential to ensure the mound system’s performance during heavy rainfall. This includes checking for signs of system failure, such as pooling water, odors, or unusual vegetation growth. Additionally, the system’s aeration and dosing pumps should be inspected and maintained according to the manufacturer’s instructions.

Soil Suitability and Infiltration Rates

The soil composition within the mound system plays a critical role in handling excess water during heavy rainfall. Soils with high infiltration rates, such as sandy loams, can handle larger volumes of water than those with low infiltration rates, such as clay soils. For instance, a soil with an infiltration rate of 10 inches per hour can handle approximately 3.5 times more water than a soil with an infiltration rate of 2.5 inches per hour.