Sites with greater than what percentage slope are considered unsuitable for development?

In the context of land development, slopes play a crucial role in determining the suitability for construction and other developments. A slope of greater than 30 percent is generally considered unsuitable for development due to the increased risk of erosion, landslides, and other geological hazards. Steeper slopes can complicate drainage and increase the likelihood of runoff, which can lead to further destabilization of the land.

Developments on such steep terrains may require extensive engineering solutions and can significantly increase construction costs, not to mention long-term maintenance challenges. Environmental impact is also a concern, as steep slopes are often more sensitive to disturbance, which can adversely affect vegetation and wildlife habitats.

Setting the threshold at 30 percent reflects a balance between recognizing the physical limitations of the land and ensuring safety and sustainability in development practices. Other slope percentages mentioned are often seen as more manageable for development, with 10 percent and 20 percent generally considered acceptable for various types of construction, assuming other environmental conditions are met.