Steep slopes are an existing conditions feature where the slope of the ground is above a certain specified slope. It is also common to find on a plan two zones for steep slopes depending on the municipality within which the site is located. One zone would be precautionary slopes and the other zone would be prohibitive slopes.
A common range for precautionary slopes is 15 percent to 25 percent with prohibitive slopes commonly being 25 percent or above.
How Steep Slopes Are Represented on a Plan
You can usually see what areas of a site are considered steep slopes through a special hatch pattern that should be shown in the plan legend. This hatch pattern would also most likely be shown over the corresponding existing contours.
The areas of the existing contours that would be hatched are determined by the local municipality. There should be regulations regarding what areas have to be shown as steep slopes and which areas are exempt from having to be considered areas of steep slopes.
Where to Find Regulations Related to Steep Slopes
The regulations related to steep slopes would most likely be found in the zoning ordinance established by the local municipality. This ordinance should have sections that define the different steep slope zones and set the criteria for what existing contours have to be shown on proposed land development plans as steep slopes.
The zoning ordinance would list what construction is allowed and not allowed in the areas of steep slopes.
Steep Slopes Can Affect Your Project
The existence of steep slopes on a site can affect the proposed layout of a land development project depending on the location and the amount of the steep slopes. The accurate representation of any steep slopes is critical to the proper design of your project.
Related: What Is a Typical Ground Slope?
Related: 7 Ways to Find the Slope of Land