Abstract:
The water represents a regeneration natural source, vulnerable and
limited, essential element for life, determinant factor in maintaining the
ecological equilibrium. The drainage of a water course is made from a
ramification of affluent values directly or indirectly to the water flow,
considered the main element of drainage. The valleys collect the part of
precipitation and aquatic plants, which are transmitted to the main water
flow. The hydrographical reservoir, of reception of collector of drainage
represents the territory surface from which the waters resulted from the
precipitations and the underground waters gravitate and penetrate in the
drainage ramification. In the drainage area take place all physical processes
which determines the hydrological drainages. The hydrographical reservoir
conditions the river life. All elements of rivers drainage depend on its
characteristics. The hydrographical reservoir is limited by the watershed
defined as the line of the eminences from which the superficial drainage lead
to the evacuation drainage. Due to the general modelation of relief by the
exogenous factors, but especially for the rivers regressive erosion the
watersheds represents a mobile element in time. The writing presents general
aspects regarding the drainage of Gorj district; the climatic characteristics
and pollution sources of main rivers. To evaluate the quality of surface
waters samples were cropped from rivers like: Sadu, Balteni, Racari,
Amaradia, Hurezani, Negoiesti, Albesti and the saprobiological index,
dissolved oxygen, biochemical consume of oxygen , the suspensions, the
chlorides and constant residuum were determined. After the accomplished
determinations it was established that the value of saprobiological index for
district rivers is of 2.3 fact which indicates a satisfactory ecological state ( β
mezosa sample ), the content of dissolved oxygen which has bigger values
than the limit of the second class for the analyzed rivers, the evolution of
suspension indicator attained the biggest value in 1999, the evolution of
chloride indicator and of constant residuum with the biggest value in 1997.
