Where should On-Site Sewage Facilities not be located in terms of topographical features?

On-Site Sewage Facilities (OSSFs) should be carefully sited to ensure efficient operation and to minimize potential environmental impacts. Placing an OSSF in a depression or a complex slope area that is dissected by gullies and ravines is problematic for several reasons. These areas are prone to water accumulation, which can lead to the improper treatment of sewage as effluent may not be able to be effectively absorbed into the soil. Additionally, the presence of gullies and ravines can pose risks of flooding, contributing to surface runoff that can transport untreated or partially treated sewage into nearby water sources, leading to contamination.

Selecting a location for OSSFs requires consideration of drainage patterns, soil permeability, and the general stability of the area. Areas with complex topography can complicate these factors, thereby increasing the risk of failure or environmental pollution. Therefore, proper placement in suitable areas is crucial for maintaining the function and integrity of these systems.