Slopes comprise the greater part of the landscape and as an integral part of drainage basin they provide water and sediment to streams. The slope processes include weathering, erosion, transport and deposition of the material.

Weathering is the process by which material is prepared for transport. Weathering is the response of the materials within the lithosphere to conditions at or near its contact with the atmosphere, hydrosphere and biosphere. Weathering consists of a movement towards a more stable state where mineral assemblages formed under conditions of high pressure and temperature adjust to new conditions under low temperatures and atmospheric pressure at the surface of the earth. This process has a long response time. Rocks change to bring equilibrium. The changes include massive clastic and plastic change, and involves preparation of the rock for transportation.

Soil erosion on slopes is closely related to rainfall characteristics, hence under conditions of increasing precipitation particularly in the tropics, the rates of loss of soil will increase, so will overland flow and runoff and the sedimentation in the channels and lakes. The runoff is the water which flow on the land surface without infiltrating into the soil. It only takes place during a rainstorm event or immediately afterwards.

This section presents the geomorphological responses of slope processes to climate change. For further information on weathering and erosion read the relevant sections on erosion by agents of wind and water.

   Stop and Think!

Explain the processes which cause the features shown in the pictures on the right side.