Erosion and deposition shape the landscapes that we see today, creating new landforms as they shape. But erosion also pollutes rivers by carrying chemicals, fertilizers and pesticides away from where they were originally applied.
Physical forces such as turbulent waters, longshore drift of coastal currents and howling winds can all play a part in erosion. Once these forces lose enough energy to cause further erosion, any material lost from it becomes deposited elsewhere.
What is Erosion?
Erosion is the slow, natural wearing away of Earth’s surface. This process creates valleys, sculpts coastlines, makes streams and rivers murky, causes mountain slopes to wear away over time, or can help uncover fossils in sedimentary rocks.
Rainfall can be one of the major forces causing erosion, particularly when it is intense and frequent. When raindrops hit the ground and dislodge soil particles, this causes splash erosion; sheet erosion occurs when runoff accumulates into streambeds before moving downstream; while gully/rill erosion occurs when water erodes streambanks/riverbanks.
Wind can also contribute to erosion by picking up and transporting weathered rock material and depositing it elsewhere, creating new landforms. Glaciers also play their part by slowly carving valleys and mountains into existence. Human activities like farming and land clearing expose dirt exposed to strong winds and flowing water while climate change makes some places more vulnerable due to variations in rainfall/temperature and by inhibiting plants from growing to hold back soil in place.
What is Deposition?
Deposition, the opposite of erosion, refers to the act of depositing materials from one location to another via wind, water, seawater or ice. Deposition may take the form of pebbles, sand or mud deposits or salt dissolved into water sources which deposit materials such as animal or plant remains or even decayed matter from previous organisms or vegetation species.
Deposition can take place slowly or quickly. For example, the Grand Canyon was formed over millions of years by Colorado River’s currents carved by river bed material, becoming a geological marvel of five-thousand foot depth and becoming one of the seven natural wonders in existence today.
Erosion depends on a range of factors such as climate, soil condition, vegetation density and topography; human activities can further accelerate erosion rates.
What is the Role of Vegetation in Erosion?
Vegetation can help mitigate erosion by intercepting rainfall, preventing splash erosion, stabilizing slopes and restraining sediments. Furthermore, vegetation helps reduce runoff water by infiltrating it deeper and slowing its flow over a slope.
Vegetated soils often exhibit lower erosion rates than their bare counterparts due to interception of rainfall, improved surface roughness and root binding effects. Furthermore, vegetation helps mitigate runoff and sediment loss through interception, infiltration, soil reconsolidation processes, organic content generation, root mass growth and residual binding effects (Hozo et al, 2005).
Erosion resistance increases with plant type and spacing, such as including herbaceous and woody species. Furthermore, root systems with strong tensile strength that extend laterally are key in terms of protecting soil against erosion – with rhizomes having high tensile strengths and reduced root-to-soil contact areas being particularly effective against erosion control strategies than taproots.
What is the Role of Water in Erosion?
Water erosion refers to the removal of weathered materials by flowing water and their transport away from their source, whether natural or exacerbated by human activities such as clearing forests or overgrazing land near streams and rivers. Water erosion is a natural process which is made worse by human activities like clearing forests or overgrazing land near streams and rivers, leading to the loss of topsoil which has serious implications for agriculture and ecological landscapes.
Water erosion comes in different forms, from splash erosion and surface flow erosion, channelised flow erosion and rill and gully erosion – to more serious forms like rill and gully erosion which can alter landscape significantly.
Wind erosion occurs through transporting dust, sand and other materials into the environment; wind can also erode rocks by abrasion and impact, leaving features like the towering sandstone arches at Arches National Park in Utah as evidence of its power. Other forms of physical erosion include glacial retreat and tunnel erosion: in which glaciers remove rocks over time as they melt back down while fast-flowing stream waters scour and slump across riverbanks or landforms respectively.