Maitrise et gestion intégrée des eaux pluviales dans les bassins versant des rivières Cari, Kidumbugwe et Nyabagere : cas de la zone inondée de Mirango II et Carama I

Abstract

This thesis work at the end of the master cycle concerns the master degree in integrated rainwater management in the Northern district of capital of Bujumbura, among others: Mirango II district of the Kamenge zone and Carama I of the Kinama zone. The Mirango II district concerned is bounded by 15th avenue to the North,RN1 to the East, Buyengero avenue to the West as well as the 6th avenue to the South, while the Carama I district is bounded by 15th avenue to the South, the border of the Gatunguru district to the East, the limit with CaramaII to the North as well as the road from the Kinama market to the West. This locality is often marked by heavy flooding, which makes life difficult for the urban population of this area. These floods originate from the passage of the three rivers originating foothills of the Mirwa overlooking the city of Bujumbura, passing through the strong flows charged and high speed because of the steep slopes to throw them definitively into lake Tanganyika. These are the Kidumburwe, Cari, and Nyabagere rivers emanating from the two watersheds; Kidumburwe and Nyabagere, Cari being a sub-basin of the Nyabagere river. After having analyzed various problems and consequences caused by these floods, we carried out both hydrological and hydrolic studies that could give the major idea to the mastery and management of these torrential waters which destabilize urban life from an economic and social point of view by taking human lives,goods,and disrupting roads transport. The main objective of the work is to improve the condition of rainwater sanitation in the above mentioned districts by modern techniques allowing to change harmful behavior of the flows of scatted surfaces by proposing new methods of delaying the concentration time, infiltration/or retention-restitution of floods. To achieve this objective, I collected the pluviometric and spatial data of the floods which were subsequently processed to analyze and discuss the result obtained. The hydrological calculation methods used to determine the project floods are: the advanced rational method and the SCS (Soil Conservation Services) method.