Interpretation of Aerial and Satellite Images (Part XVII)

River land types have been created by erosion, displacement and sedimentation of unset materials through the flow of water. The type of river basin that are required to be described are butterfly alluvium, flood plains and deltas. The ability and capability of water to erode and transport soil and particles of rock depends on the speed of water and size of particles. Particle erosion, as compared with the continuous displacement of materials, requires great water velocities. When the velocities are less than certain limits, sedimentation occurs. Larger particles are thrown out and lined up along the river bed (bed load). Smaller particles are taken up and forwarded to the front (Suspended Load). Particular particles, especially sand particles of the same size, may be suspended or moved at different times depending on the speed of the river. Small particle erosion requires considerable speed, but as soon as they are displaced, they can be moved at different speeds of the river. The largest erosion and sediment transport occurs during the flood period. Increase in velocity and volume of water leads to an increase in the size and volume of materials that can be carried. The term "river capability" refers to the maximum particle size that a river can carry at a given speed.