War Ground

The degradora action if becomes much more fast, being able to remove, in few years, the layer that the nature took millenia to form. (PEIXOTO, 1926, pg. 74) According to War (2003), the eroded material of a hidrogrfica basin can cause the assoreamento of rivers and reservoirs. Moreover, the particles carried for the water, in an agricultural area, can be impregnated of agricultural defensives and to contaminate waters of the rivers. The deforestation and the erosion of ground can provoke the disappearance of sources, as well as accenting the effect of floodings. The erosion is presented as a great ambient problem for the society that in turn, contributes in many cases for the acceleration and dinamizao of the erosive processes, resulting in ambient and economic problems. One perceives then that the main erosive processes caused by the hidrolgica action are: erosion for impact of the rain drops in the ground (effect splash), laminar erosion or in sheet, and linear erosion or for concentrated flow. The laminar erosion occurs through the diffuse superficial draining of the water of rain.

When the draining if concentrates through well definite lines of flow, three types of linear feies can be generated: ridges, ravinas and soil erosions. With the development of the erosive processes, in function of the occupation of the ground, the losses of ground for erosion are lead by multiple factors related to the natural conditions of lands, being distinguished: rain, the vegetal covering, the topography and the types of ground. The man, when removing the vegetal covering, diminishes the capacity of the ground to hold back the water of rains, what he can increase the risks of erosion, floodings, assoreamentos of rivers, etc. the vegetal covering of a condition of conservation of a land against the erosion. He enters the main effect of the vegetal covering, detach the following ones: ) the protection against the direct impact of the rain drops; b) energy dispersion and in addition of waters of superficial draining; c) increase of infiltration for the production of pores in the ground for action of the roots; d) increase of the capacity of water retention for the estruturao of the ground for effect of the production and incorporation of organic substance.