![]() ![]() Many streams develop curves in their channels called meanders (figure 4). Now the stream does more work eroding the edges of its banks. As a stream moves into lower areas, the gradient is not as steep.This stream begins as snow melt from the mountains. The stream moves fast and does lots of work eroding the stream bed.įigure 3. At a stream’s headwaters, often high in the mountains, gradients are steep (figure 3). As a stream flows from higher elevations, like in the mountains, towards lower elevations, like the ocean, the work of the stream changes.Stages of Streams: headwaters, meanders, braided streams, floodplains, base level. ![]() Streams with high velocities and steep gradients do a great deal of down cutting into the stream bed, which is primarily accomplished by movement of particles that make up the bed load. The bed load particles, the largest particles of sediment transported by a stream, spend most of their time on the bottom of the stream channel, rolling, sliding, or saltation (when small pebbles and gravel move up and down along the water flow). Bed load: Bed load consists of particles too large to be suspended in the moving current of water for an extended length of time.During flood stage, the suspended load greatly increases as stream velocity increases. Rivers carry sand, silt and clay as suspended load. Streams with a steep gradient (slope) have a faster velocity and greater competence.įigure 2. Streams that carry larger particles have greater competence. The size of particles that can be carried is determined by the stream’s velocity (figure 2). Suspended load: Sediments carried as solids as the stream flows are suspended load.These ions are usually carried in the water all the way to the ocean. Dissolved load: Dissolved load is composed of ions in solution (e.g.Streams transport clastic sediment in two ways depending on the size of the particles. Several factors cause a stream to slow down, including the stream channel widening, the stream overflowing its banks and spreading into a floodplain, the stream gradient (downhill slope) diminishing, and the stream emptying into a larger, slower moving body of water. The stream starts to deposit sediment, beginning with the largest pieces. As a stream slows down, its competence and capacity are reduced. The competence of the stream is the size of the largest particle it can carry. Capacity depends on how fast the stream is moving and its total discharge. The capacity of a stream is the total amount of sediment it can move. ![]() Faster-moving water has greater competence and can move larger pieces of sediment. The competence of a stream refers to the maximum size of the pieces of sediment it can move. The faster a stream flows, the more energy it has and the larger pieces of sediment it can transport. Sufficient energy in the stream is required to dislodge rocks from the earth and move them. Streams also carry ions and ionic compounds that dissolve easily in the water. Most rocks and minerals are much denser than water. Erosion by Streamsįlowing streams pick up and transport weathered materials by eroding sediments from their banks. As streams flow towards the ocean, they carry weathered materials. ![]()
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