Search for streams that become muddy after it rains; this indicates soil loss that could result in flooding and other issues.
Erosion occurs when soil particles are transported away by wind, water or ice and deposited elsewhere; often in rivers. Erosion may also introduce harmful contaminants that threaten our drinking water supply.
Wind
Wind erosion is a natural process that affects sandy soils. It is particularly prevalent in desert regions with plenty of dry land that erodes quickly. When this happens, soil particles become airborne for hundreds of kilometers before eventually landing back at another location. Erosion depends on particle size, adhesion to ground surface particles, wind velocity velocity and rate. Land clearing activities, overgrazing livestock or cropping increase susceptibility to wind erosion.
As glaciers, rivers or winds lose energy they lose the ability to transport eroded material; deposition takes over. Eroded materials sink to the bottom of streams or to the ground where they build deltas, spits or beaches; river deposits consist of rocks, pebbles and silts while rocks may be carved by water into structures like “mushroom tables” found in Egypt’s White Desert or ventifacts sandstone pillars known as ventifacts.
Water
Water is a potent erosional force, carrying away bits of soil and rock as it flows over them, depositing them at different spots along the riverbanks. Particle size determines where these deposits occur: clay particles travel further while sand particles remain near where they were first eroded.
Streams constantly erode the land they travel across, particularly along their outside curves and meanders, leaving wide expanses known as floodplains behind them. Furthermore, streams may create deltas or alluvial fans as they slow down.
Ground water can be an erosive force, particularly when it dissolves carbonic acid from limestone rocks and wears away at them slowly over time, creating caves that span multiple football fields long and tall, complete with stalactites and stalagmites growing inside them.
Human activity that contributes significantly to erosion includes clearing forests and plowing up grasslands for farming or development purposes, leaving no vegetation to hold onto soil particles which then wash or blow away, leading to flooding or land slides.
Landslides
Landslides, also referred to as mass wasting, involve the downward movement of rocks, dirt and debris from mountains or cliffs. Landslides can range in size from small to extremely large; occurring in many environments and providing mass waste that can be divided into five categories: Rock falls, topples, slides, spreads and flows.
This new model successfully accounts for erosion-induced momentum production while providing the first mechanical quantification of energy consumption and an accurate description of mobility, thus answering an age-old question regarding why some erosive landslides generate higher mobility while others exhibit reduced mobility even under similar erosive conditions.
Modeled using momentum plus frictional forces, landslide change inertia equals momentum plus frictional forces. Momentum depends upon internal and basal friction angles, viscous drag, slope of bed and viscous drag forces; acceleration occurs when velocity surpasses slope of bed while deceleration occurs as velocity approaches surface of material underneath it.
Sediment
Many geologic features can be traced to sediment transport. A stream carrying glacial silt may transport particles to a tidal bay and intermix with local rock types like basalt near volcanic plate boundaries or limestone found in historically shallow marine regions 20.
Transport of sediment leaves evidence of its history behind in the form of structures deposited on its bed or preserved within rocks that contain it, such as ripples that indicate flow direction or scour holes behind boulders, flute casts (troughs in soft sediment that fill with raindrops or can be filled by them), flute flutes or their casts (flute casts) being present indicate that sediment was exposed briefly at the surface before rapidly being covered over.
Human activities can contribute significantly to an increase in sediment in water bodies. Logging, mining and construction sites expose and loosen soil that is then carried to nearby streams by rainfall or runoff. Hardened shorelines also interfere with natural tidal erosion by restricting beaches’ ability to absorb new sediment and “grow” wetland habitats.