Erosion is a process that causes the soil surface to wear out; geological erosion is caused naturally by water, wind or gravity, and accelerated erosion is caused by human use of land. Geologists estimate that 70 percent of soil erosion is caused by human activities like excessive construction, agriculture, surface mining and forestry.
The rate at which soil erodes depends on the area's climate, topography, soil type, land management practices and vegetative cover. Removing the vegetative cover accelerates erosion, which is often caused by grazing, logging or cultivating. In some cases, it can be removed by pests like pigs, rabbits and goats.
When the vegetation is removed, huge amounts of soil are lost through erosion, especially in times of storms. The eroded soil is normally washed into waterways, and this leads to decreased clarity of water. Once the eroded soil is in the waterways, it can choke life such as fish, and the increased nutrients in the water can support the growth of unwanted animals and plants. The soil particles are then carried by the water downstream to the coast, leading to higher amounts of sediments in the harbors. This is also dangerous because it causes upstream floods and poor clarity of water.