In a serial distribution system, the relief pipe must connect with the higher trench's top at what level?

In a serial distribution system, the relief pipe plays a crucial role in ensuring proper drainage and function of the septic system. For the system to operate effectively, the relief pipe must connect with the higher trench's top at a level above the gravel. This is important because positioning the relief pipe above the gravel level allows for proper fluid flow and helps prevent any backflow or blockages that could occur if the pipe were located lower.

By maintaining the connection above the gravel, the system is more likely to allow effluent to flow freely from the higher trench to lower levels without being impeded by gravel or soil, which can absorb excess water and create saturation issues. This placement also helps facilitate aeration and drainage, which are essential for the natural processes involved in wastewater treatment.

In contrast, connections at the midpoint of the soil or below the surface may result in inefficient drainage and potential over-saturation of the soil media. Connecting at the same level as the gravel can also lead to similar issues of obstruction or inadequate drainage. Thus, positioning the relief pipe above the gravel level is optimal for ensuring the efficient operation of the serial distribution system.