Lecture 3

Soil Erosion• Runoff occurs when precipitation or irrigation waterexceeds the infiltration rate of a soil, causing water to rundownhill due to gravity, often carrying loose soil materialin the overland flow.• The greater the angle and the longer the slope, thehigher the probability for erosion.• Soil erosion due to water can result in several onsite andoffsite problems (Table 3.3 in handout). The amount ofwater that infiltrates or runs off a soil is often determinedby the position of the soil in landscape. Relief, alsocalled topography, is the physical landscapecharacteristic that refers to angle and length of the slopeand proximity of the surface to the water table.