Erosion and deposition are processes that alter Earth’s surface. Wind, water and ice are among the primary forces responsible for erosion.
Erosion removes bits of rock and soil, shaping mountain ridges, carving waterfalls and creating alluvial fans and deltas along its course.
Different forms of erosion require different flows of water in order to be effective; faster-flowing streams tend to erode more quickly while slower moving rivers do so more gradually.
Runoff water plays an integral part of the water cycle. It flows over land surfaces or into bodies of water like streams, rivers, lakes or oceans and flows over their surfaces to eventually enter bodies such as lakes, rivers or oceans. Runoff can bring fine soil particles with it which contribute to sedimentation in these bodies of water resulting in oxygen depletion as well as algal blooms which kill fish populations while simultaneously degrading water quality.
Erosion begins when raindrops strike the ground, dislodging soil particles and carrying them away with them via splash erosion, sheet erosion or rill erosion.
Activities such as road construction, building construction, logging, poorly managed farming and landscaping remove natural protections of soil from runoff erosion, leading to runoff-eroded runoff from highway construction often carrying pollutants downstream into surface waters that were downstream from their construction sites. To combat this pollution it is crucial that a comprehensive erosion and sediment control (ESC) plan be put in place prior to earth moving activities taking place.
Landslides refer to the movement downslope of rock, debris or soil (or combinations thereof), caused when forces holding a slope together are overcome – for example by earthquakes, erosion by flowing water or glaciers, weathering processes (freeze thaw cycles or mineralogical changes) etc. Earthquakes, erosion caused by flowing water or glaciers and weathering effects all can reduce a slope’s strength over time and lead to its collapse.
Landslides can be divided into several distinct classes. They include falls, topples, translational slides and lateral spreads or flows. Falling blocks of material that slide downhill are known as falls; loosely moving materials that separate from steep mountainside layers known as translational slides or lateral spreads are classified as translational slides or flows.
Landslides, more commonly referred to as debris flows, are fast-moving masses that often cause flooding. Debris flows can obliterate homes, cut roadways and railways, cause deadly accidents, and have even claimed lives in some cases. Humans have often become the primary force responsible for altering landscapes by building roads and cities, mining for metals and minerals, or developing agricultural lands.
Avalanches are one of the world’s deadliest natural events, capable of destroying buildings, bridges and people while also burying or carrying away animals and people alive. Many victims die due to asphyxia from not enough oxygen as the flow pushes through snow-packed rocks causing asphyxiation.
Understanding erosion-deposition processes of avalanches is integral to accurately forecasting their impact area and runout zone. This study conducted a small-scale experiment to explore these rates of erosion-deposition with yellow sand avalanche over an erodible red layer covering an inclined plane bed, depending on its volume release; depending on this, its course could either decay slowly over time, reach steady state, or rapidly shed grains to form secondary avalanches.
Estimation and characterization of sediment concentration and organic fraction are obtained through grid sampling along a channeled avalanche path at various times in winter 2006, 2007 and 2008. Avalanche sediments depositing on preexisting soils create complex pedo-environmental conditions with buried or truncated horizons and nutrient-rich deposits.
Waterfalls form when rivers encounter areas of rock which erode more slowly than the rest, transforming its flow into rapids as it traverses over these slower-eroding rocks.
At some point, rushing streams will erode rock to a point where it slopes vertically; this stage is known as waterfall stage or cascade/cataract stage.
As streams continue to erode, they deposit sediment–from microscopic silt, pebbles, and even boulders–into their streams, carrying microscopic silt, pebbles, and sometimes boulders with them. Over time this accumulation of sediment helps erode soft rocks such as sandstone or limestone beds until only hard rocks such as granite remain. Over time this creates mesmerizing waterfall landscapes we see throughout nature thanks to erosion’s master sculptor: erosion. Just one way erosion transforms Earth’s beauty into its beauty is through erosion’s creation of waterfall landscapes; erosion masterfully carves out its natural beauty sculpting Earth’s beauty into its entirety!