The petrologic study of gneiss of Bunhyakiri in the South –Kivu province in the Democratic Republic of Congo. The following lithologies were identfied: the gneiss was subdivised in gneiss “oeillés”, granitics gneiss and leptyni, and the pegmatit was subdivised in pegmatit contens tourmalin and pegmatit contens biotit. The chemical analysis had shown that the gneiss of Bulambika was born from metamorphic evolution of medium and acid rocks (granit, granodiorit, tonalit). This lasts are peraluminous and belong to one magmatic series which is calcoalcalin sery. It means that they are magmatic rocks which come from mantel and they were formed in subduction context. These formations are, to the mineralogic point of view, rich in feldspaths (±55% of proportion) where the albit dominate. They are belonging to the class of Kibarian granitoids of the group of Bitale.

This study carried out in the cheap one of Bukavu, precisely in the southern part, on water of the sources. It was carried out under two aspects: aspects quantitative and qualitative. The first aspect consisted with the taking away of the flows on the various sources to compare them from/to each other. It was noted that the flows vary from a source to another: the Kabangere source is most significant, with an average of 29,87.10-5 m3/S, followed by Brigignon 10,89. 10-5 m3/S, Hewa Bora 8,93. 10-5 m3/S, Mushununu 7,75. 10-5 m3/S, Swimming pool 3,83. 10-5 m3/S and, finally, Kaba T ate 3,15. 10-5 m3 / S. L be five last sources have medium flows varying from 3,15 to 10,89.10-5 m3/S. the second aspect which was limited on the qualitative analysis consisted in measuring the contents of chemical elements dissouts in water of the sources to compare them with their relative concentrations recommended for a drinking water by the standards of WHO (World Organization of L has Santé) and supplemented by the measurement of the physicochemical parameters such as the pH, conductivity, the temperature. This study proved that water of our sources is all drinkable, and thus, clean and without danger to consumption.