QUALITE BIOLOGIQUE DU RESEAU HYDROGRAPHIQUE DU BASSIN VERSANT DE LA SOUMMAM (NORD DE L’ALGERIE)

Abstract

The objectif of this study is to draw a map of quality or health of the river system watershed of Soummam by using standard global biological index (IBGN) of AFNOR (1992) and identify the most degraded sections of the watershed. The assessment of the biological quality is based on the general principle according to which each type of natural environment has its own characteristics community of organisms. Any degradation of the natural organisms indicates that some disturbance has occurred. Benthic invertebrate community were sampled on three areas of watershed of Soummam, in a total of 34 stations were sampled between 20m and 1100m of altitude between 2004 and 2010. The environmental quality is good in 5.9% of the stations where the index IBGN values displays 13 and 14, which meant that is not far from the fair quality, since these values are located just to the boundary between good and fair quality. A fair biological quality in 26.5% of stations, a bad quality in 52.9% of stations and finally, a very poor quality in 14.7% of the stations