Rwanda: Cause of water pollution in crucial waterways

The Democratic Green Party of Rwanda launched research findings on Water Pollution study on the Nile Basin area in Rwanda-Case study, River Nyabarongo on 16th October 2021. The study was done between April-Otober 2021. It was conducted by several party scientists headed by Dr.Jean Damascene Gashumba who was deputized by the Party’s Environmental Commissioner, Jean Marie Vianey Mwiseneza.

Nyabarongo is the major and longest River in Rwanda, with a total length of 351 km (218 miles). It begins its course at the confluence of Mbirurume and Mwogo Rivers in South-western part of the country. Flowing north, then south-east and passes through Kigali Capital City. The city is rapidly expanding with increased population growth 4.0% per year (Nduwayezu et al., 2016) which results into anthropogenic activities such as Agriculture, industry, mining, household, car-garages and so on. This expansion has negatively affected water quality and wastewater management in the city. Therefore, there is elevation level in pollution which has been reported in Nyabarongo River which is major source of River Nile.

The main objective of the study was to produce a situational assessment report on the pollution of the water of Nile Basin and its associated Water ecosystems Basins in Rwanda, whereas the specific of objectives are the following:

  • Identify the major source and type of water pollution in Nyabarongo River.
  • Find out the effects of Nyabarongo river pollution on ecosystem around the river
  • find out challenges with regards to the protection of Nyabarongo River.
  • Find strategies and policy recommendation for the protection of Nyabarongo River.

Causes of water pollution in Rwanda:

–          Mining waste: The water draining the mining sectors of Rutongo and Gatumba pollute River Nyabarongo and Nyabugogo swamp by sediments of clay and sand which they transport over long distances. It is this considerable mineral load which partly gives the brown water color that is characteristic of several rivers in Rwanda. Mining and quarrying produce massive rejects which appear in nature in the form of enormous lots of earth and rocks.

–          Household waste: There has been an increasing concern about household waste collection and treatment. Solid wastes, rubbish, garbage and sewage are being produced everyday by city residents and this is also one of the main causes water pollution.

–          Agricultural waste:  Rejects from agricultural waste and poor methods of farming leading to soil erosion have dramatically polluted river Nyabarongo.

–          Industrial Waste: The industrial effluents and by-products are directly discharged in the water bodies. These industries have been responsible for water pollution through their chemical discharges. The textile industry, the iron industry and Kabuye sugar factory are one of the main pollutants.

–          Car garage waste: They are many different chemical substances and processes used at an auto mechanic workshop, which are potentially dangerous both to the environment and to the health of human beings as well as animals. It was clear from the results of the analytical studies of the physicochemical parameters and heavy metals determination of both soil and groundwater from auto- mechanic villages that there is a high degree of contamination and pollution. This expansion has negatively affected water quality management in the city, especially wastewater management. Elevated levels of pollution have been reported in some of the major rivers passing through the City of Kigali, such as Nyabugogo River and Mpazi River. The Nyabugogo Swamp feeds into the Nyabarongo River and is major outlet of the City of Kigali and it receives all the wastewater from City.

Research Findings on Source of pollutants:

–          Household wastes are 45.6% (n=41),

–           Industrial wastes 15.6% (n=14),

–          Car-garage 13.3% (n=12),

–          Crop harvesting 7.8% (n=7),

–          Wastes from livestock 6.7% (n=6)

–          other sources that actually lead to pollution in Nyabarongo river at the rate of 11.1% (n=10)

Click here for details of the findings, effects and recommendations.


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