It ranges from the small scale of rill formed by erosion on a newly exposed surface to the continental scale drainages that evolved over long geological times e. Figure 1 shows some example of a dendritic drainage pattern. How do branching drainage networks get started and what controls their evolution? Figure 1 Left, Dendritic drainage pattern on the Western Plains oblique view from an airplane. Right, Dendritic drainage pattern in Yemen space shuttle photograph. Overland flow runoff of waters with erosive potential is generated when the volume of water supplied from rainfall or snowmelt exceeds the infiltration capacity of the soils or substrate.
Infrequent but substantial rainfall events may be sufficient to generate runoff in which the shear stress of overland flow exceeds the shear strength of the surficial materials such that weathered or loose particles are eroded and transported down slope. Spatial variation in surface topography of the slope and texture of the slope sediments often leads to gulling for landscapes where low vegetation cover and root mass are insufficient to stabilize the surficial materials.
These are sometimes referred to as wash dominated slopes in which the rate of fluvial erosion, although infrequent, exceeds the rate of weathering which supplies the erodible sediment. Climatic variables play a key role in drainage form, slope form and process, and in the evolution of a drainage basin through time. Annual variations in temperature, precipitation, and seasonality of precipitation work together to influence the degree of chemical and physical weathering of slope materials, the depth of weathered materials or soils that develop, and perhaps most importantly, to determine the vegetation type and percentage of cover across a landscape.
Vegetation covers in turn controls slope form and mass movement process and therefore the resultant drainage basin attributes. Vegetation cover is high, protecting the surface from rain splash, and the root mass is sufficient to stabilize the materials on the slope. In the temperate climate landscape, downslope movement of materials to the fluvial channel occurs primarily by the slow mass movement process of either continuous or seasonal creep.
Hiking trips and adventure challenges are often based around landforms, such as the Three Peaks Challenge in the United Kingdom, where you have to trek to the top of three landforms.
Rock climbing up, or abseiling down landforms is another popular activity and, for the more adventurous, some tour companies offer potholing and caving trips. For all of these activities it is best to start with beginner level programs, before progressing to more complex and dangerous landforms.
Geothermal energy is a renewable energy source obtained from hot rocks deep underground. Landforms, particularly volcanoes, are key sources of geothermal energy and so landforms, and the areas surrounding them, are often harnessed for electricity and hot water production.
Another renewable energy source, wind power, can be harnessed using farms built in elevated areas. Landforms are often in the ideal location for these wind farms as they are in remote, windswept locations at high altitude.
Renewable energy, unlike coal, oil and gas, is made from resources that occur naturally and so will not run out or pollute the atmosphere.
Updated April 25, How to Read Elevation Maps. What Are the 4 Main Types of Landforms? Forces That Cause Landforms. How to Explain Topography. What Are Four Major Landforms? What Are the Most Common Landforms? Landforms Near Chicago. Weather of the Grassland Ecosystem.
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