Which two factors are key considerations when evaluating a topography site?

When evaluating a topography site, the combination of slope and potential for flooding is crucial for determining the suitability of the location for an on-site sewage facility (OSSF). Slope plays a significant role in how water drains away from the site. A steep slope can increase erosion and lead to runoff issues, while a gentle slope may offer more stability for systems that need gravity flow.

The potential for flooding is equally vital because areas prone to flooding can jeopardize the integrity of sewage systems, leading to contamination risks and system failures. Ensuring that the site is not at risk of flooding helps maintain the effectiveness and safety of the OSSF, as well as protects the surrounding environment from harmful effluent.

Other factors, such as soil type and water table level, are important but may come as secondary to understanding the interplay between slope and flooding risks. Knowing how the landscape can affect these systems is fundamental for installers in selecting appropriate sites that ensure compliance, protect public health, and preserve environmental quality.