Class

Slope Angle

Landform

Process Erosion

Activities

Suitability^*

1

0˚ - 2˚

Floodplains, terraces, and surface erosion.

Minimal soil loss and no landslides

Mechanized agriculture, urbanization, and roads.

High

2

2.1˚ - 5˚

Soft ripples, valley bottoms, and tabular surfaces.

Start of solifluction, diffuse and laminar flow; furrows.

Some conservation farming. Acceptable for urbanization.

High with limitations

3

5.1˚ - 15˚

On hillsides, monoclines, and structural reliefs.

Mass movements, creeping laminar flow, landslides, furrows, and ravines.

Moderate to intense conservation farming. Mechanization impossible >7º. Poorly suited for urbanization and infrastructure routes.

Moderate

4

15.1˚ - 25˚

Mountainous slopes, escarpment failures and terraces.

Strong linear erosion, soil destruction, landslides and falling blocks.

Farming and forestry. Unfit for urbanization and infrastructure.

Moderate with restrictions

5

25.1˚ - 35˚

Hogback-type structural relief, coastal cliffs, and ridges.

Strong linear erosion, destruction of soil, landslides, falling blocks, and avalanches.

Forest use.

Partly restricted

6

>35˚

Walls and cliffs in canyons or very enclosed valleys, and cornices.

Mass falls, landslides, and collapses.

Limited forest use.

Restricted