Canyons are created, nearby hills are flattened and the river bed has broadened. Lesson overview: How do rivers shape the land? The lower course is unique as this is the stage in which a river has reached sea level. Dissolving materials by corrosion mean that the river moves eroded rocks in solution down the river. River processes shape the land in many ways and by many means. Old rivers often appear incredibly muddy and slow-moving, as the sediment they carry is suspended through all layers of the river as it make its way downstream. In this lesson, we will be learning about how rivers shape the land. Deltas form when the river leaves sediment at its mouth meaning that the river splits into many narrow channels instead of one single river mouth. As rivers leave their source mountains or hills, they look more like the familiar view of a river, wider, slower, and gentler, changing course more slowly. Old rivers have lesser gradients than do young rivers, and their floodplains are wide; young rivers have incredibly steep gradients and rarely a floodplain to speak of. The river gains energy as it flows down the slope (or gradient) from its headwaters to sea level which can vary depending on the landscape and the river. Young rivers erode the rock and soil quickly in order to achieve equilibrium between the altitude of their headwaters and their final expulsion at sea level. They provide dry inland areas with much needed fresh water and allow climates of every type to support life. Old Sarum, near Salisbury, originated from ancient settlement in a meander. The river Nile in Egypt has a delta. Rivers can make land fertile when they flood or bring misery to householders because man has built his settlements in the wrong place. Rivers carve channels through rock. RIVER PROCESSES + LANDFORMS How do rivers shape the land? Brooks and streams combine to form the tributaries of a river. The Ancient Egyptians relied on the annual spring flooding of the Nile for their agriculture. Rivers shape the land thanks to weathering. Man’s actions too affect the rivers flow, gravel and water abstraction, irrigation and hydroelectric schemes and other activities can greatly alter a river’s flow rate. Over time rivers slow in their erosion of the geography around them but are never quite done changing the landscape completely. Solution is the result of corrosion. The river transports material in many ways. Rills combine forming brooks, which then join together to form streams. Corrasion occurs when material carried in the water crashes into the river’s bed and banks breaking more material away. When a river loses energy, it no longer has the energy to transport material and deposit it. Abrasion, hydraulic action, and solution are all the ways in which a river erodes the bank and river bed through friction between water, soil, rocks, and other natural material. Rivers still form valleys in this middle stage, but they are very different to the sharp mountain valleys, being deeper, wider, and more gentle. View in classroom. About & Disclaimer | Terms | Privacy | Contact, An Explanation of River Processes and Landforms, Interesting Facts about the River Euphrates, Lessons of the River what the River Teaches us Riparian Knowledge Find the River the Blue Danube, Hydrological Cyclegroundwater Agricultural Industry Sedimentation. We will be learning about the four types of erosion, the four types of transportation and learning about what deposition is. Lighter material continues its journey while the river has sufficient energy to carry it, eventually leaving the lighter material along the way, but the river may not drop the lightest material until it reaches its outlet to the sea. The upper course is also at the highest altitude as this is where the headwaters of the river originate. Video. The erosion rate varies from day to day and season to season. Evidence of young, mature and old rivers can be seen around the world; rivers in each stage of development can be seen twisting and turning through each unique landscape they come across on their quest to reach sea level. In the lowest river courses, the ground is even less steep and the water runs more slowly still. Mesopotamia is Greek for "[land] between rivers." As a river ages it begins to smooth out the geography of the land around it. Rivers function to get from their beginnings, or headwaters, to sea level through the most efficient path possible. Agriculture is supported by rivers and humans benefit from their existence in many ways. Hydraulic action occurs when the air trapped in crack and holes in the river is compressed, loosening material from the river’s banks and bed. Intro Quiz. Saltation is particles jumping down stream. Rivers have three sections or courses: the upper course, middle course and lower course. http://www.waterencyclopedia.com/St-Ts/Stream-Erosion-and-Landscape-Development.html, Five Tropical Cyclones in the Atlantic Basin, Satellite Imagery of the Widest River in the World, Study: Glacial Lakes are Increasing in Volume Worldwide due to Glacier Melt, New “Map Projections for Babies” Board Book Helps Encourage Early Communication and Learning, Study Finds Staggering Decline in Marine Fishery Biomass, The Only Metric Highway in the United States, http://thebritishgeographer.weebly.com/river-processes.html, http://www.waterencyclopedia.com/St-Ts/Stream-Erosion-and-Landscape-Development.html. The flow or energy of the water depends on the gradient of the land over which it flows, remembering water always flows downhill, and how much water is in the river. Exit Quiz. Cavitation occurring mainly in waterfalls is the process whereby millions of tiny bubbles emit shock waves thus weakening the rocks. Rivers begin in hills, or mountains. Melting snow or ice may feed rivers or water draining down from high slopes into a basin. The shape and size of a river depend on a multitude of factors that vary over time and space. Flowing water continually erodes the land it runs through, and over millions of years the topography of the land can be greatly changed (notice how deep the Grand Canyon gorge is). As the river loses energy, it deposits material, heavy particles first. Mature and old rivers erode laterally as opposed to young rivers, which are eroding in many different ways.