Final answer:
Stream discharge erodes and shapes landscapes through mechanical breakdown and chemical weathering, with water flow and gravity assisting in carrying sediments. The size and velocity of the stream affect its erosive power and capacity for bedload transport, leading to variations in riverine landscapes.
Step-by-step explanation:
Stream discharge performs erosive work through the volume of water moving through a river channel over time, which results in the erosion of soil particles and the dissolution of minerals. The power of stream discharge to erode and shape the landscape is dependent on various factors such as velocity, volume, and the sediment load carried by the river. The processes at work on the channel involve a combination of mechanical breakdown and chemical weathering, facilitated by the moving water's kinetic energy and its capacity to carry dissolving agents. As water flows from higher elevations to lower elevations, gravity contributes to its potential to erode land and transport sediments.
In addition to surface runoff and groundwater seepage, which contribute to river discharge, the erosive power of a stream is also related to the size and velocity of the flow. Smaller particles like sand and silt can be transported in suspension, while larger materials might be rolled or bounced along the streambed, a process known as bedload transport. Changes in river velocity due to topography cause variations in erosion and deposition patterns, leading to the formation of different riverine landscapes, such as headwater streams, straight-channel, braided, and meandering streams.