Will a Branched Drain System Work on Steep Terrain?

Design Considerations for Steep Terrain

When designing a branched drain system for steep terrain, it’s essential to consider the slope of the land and the flow rate of the wastewater. A general rule of thumb is to limit the slope to 1% to 2% to prevent erosion and ensure proper drainage. This can be achieved by using a combination of natural and constructed slopes, such as berms or swales.

Site Preparation and Grading

Proper site preparation and grading are crucial for a successful branched drain system on steep terrain. This involves removing debris, compacting the soil, and grading the land to ensure a smooth, even slope. The goal is to create a stable surface that will not erode or collapse under the weight of the wastewater. A minimum of 1 foot of compacted gravel or aggregate is recommended at the base of the system to prevent settling and ensure proper drainage.

System Components and Installation

To install a branched drain system on steep terrain, use a combination of pipes and fittings specifically designed for gravity-flow applications. These systems typically include a primary collector pipe, secondary collector pipes, and a final treatment or disposal system. When installing the system, ensure that all connections are secure and watertight, and that the pipes are properly sloped to prevent backflow and ensure proper drainage. A minimum of 1/4 inch of fall per foot is recommended for gravity-flow applications.