The Water and Sanitation Corporation Limited (WASAC) on Saturday requested its customers to bear with it after Nyabarongo water became too turbid to be treated.
"This will affect the water supply in the following areas: Nyarutarama, Kibagabaga, Bumbogo, Gihogere, Rukiri, Ruturusu, Nyagatovu, Nyabisindu, and Bibare. Rwimbogo and Gasaraba will be affected too. Bear with us,” the agency tweeted.
Turbidity in Nyabarongo is often a result of soil erosion and run-off from unregulated mining activities, among others.
Therefore, it is noted, tree planting and reducing tree cutting, proper terracing, installing stop gates and stricter regulations on mining operations are important tools to help protect Kigali's water supply.
François-Xavier Tetero, head of water resources management at the Rwanda Water and Forestry Authority (RWFA), explained that the problems have three primary causes – soil erosion from agricultural activities, artisanal mining zones, and un-tarmacked roads in rural areas.
What was done especially in the Nyabarongo case, he explained, is that the Ministry of Environment and RWFA have completed a thorough mapping of affected areas countrywide "using satellite images” and now know areas to focus on.
Prior to that, he added, there are various projects addressing the matter of soil erosion in the country.
Tetero said: "For example, we have a project focusing on one of the most critical zones in Ngororero District. It is a small zone called Secyoko, a tributary of River Nyabarongo.”
"Besides mapping all areas prone to erosion, we also use a different technology called segment fingerprinting to determine which areas contribute most to the problem. The most contributing area happened to be River Secyoko which is between Ngororero and Rutsiro Districts.”
Using available funds, he said, they prioritized this area and are now investing more than Rwf5billion in that small sub catchment area. River Nyabarongo has around 20 such sub catchments.
Among others, the Rwanda Green Fund (Fonerwa), a national environment and climate change fund that invests in public and private projects that have the potential for transformative change and that align with Rwanda’s commitment to building a green and climate resilient economy, is helping rehabilitate a catchment area that supplies Kigali.
The Yanze Watershed in Rulindo District has historically suffered from soil erosion caused by steep slopes and heavy rainfall. This has affected agricultural productivity due to reduced soil fertility and crop yields. It has also caused siltation in Yanze River, landslides and flooding.
Rulindo District, with support from Fonerwa, is protecting the Yanze Watershed by reducing river sedimentation and improving the livelihoods of communities through participatory agroforestry.
The project – with a total investment of Rwf1.9 billion – is rehabilitating 3,500 hectares of the watershed, the main source of water for the City of Kigali, through terracing, agroforestry, and buffer zone protection.
No short term measures
Asked what is done to provide short term answers since measures being implemented now look to the long term or sustainable solution, Tetero noted that when the turbidity of the river goes up, as was the case Friday night, "the good thing is that it doesn’t stay high for so long.”
"It could be one day. But normally, it doesn’t go beyond that. There are no short term things you can do to arrest that. You need to invest in those long-term measures.”
When the turbidity goes up, he said, Wasac teams only have to wait a bit for the flow to normalize and then carry on with their work.
"For the water supply issue, I am sure that even now [Saturday noon] it could have normalized.”
Aimé Muzola, the Chief Executive Officer of WASAC said: "We are trying our best to restore service today (Saturday)".
editor@newtimesrwanda.com