Ward Pink

Moreover, the final way of these waters is the rivers, that in the urban space meet entulhados and sanded for sediments extremely and industrial and domestic debris. Such facts, intensify in the diverse cities urban ambient problems, as the processes of erosion in hillsides, with prominence for the mass movements, beyond floodings, overflows and floods. The urban phenomena of floodings, overflows and floods, although to be treat in the vehicles to telecommunications of generic form, are distinct events. In accordance with the Manual of ambient Disasters (1998) floodings can be defined as the water overflow proceeding from rivers, lakes or dams. Already overflow, according to this exactly manual, occurs when the waters are accumulated in the stream beds of the streets and the urban perimeter in function of a system of deficient draining. Finally, the floods if characterize for the rise of waters of gradual form and previsible, remaining itself in full situation of during some time and following they are drained gradual. For Ward Pink apud (2010), the phenomenon of the flood is related to the relief, the ground and the lack of vegetal covering, that are collaborating elements for the occurrence, duration and intensity of this event. For this author, the rainfall is a secondary 0 variable, since the characteristics of the small farm and the consequent antrpica action in the change of the natural dynamics of the ground, relief and vegetation are that it intensifies the problem of urban floods. The ambient problems in hillsides are related to the topography of a surface, having kept a indissocivel relation to any event that diminishes or it eliminates the protective covering of the natural vegetation or damages the structure of the ground, contributing for the beginning or acceleration of erosive processes in hillsides, as the mass movements.

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