The National Water and Sewerage Corporation in Mbale extracts water from rivers Nabijo, Namatala, and Nabuyonga. However, these upstream catchments are undergoing degradation due to human activity and a general increase in the population, writesDavid Wandeka.
As the country gears up for the rainy season, officials at the Moni Water Treatment Plant in Mbale are starting to count the cost of treating and supplying water to residents. Porolofilio Tebandeke, the officer-in-charge of Water Quality at the plant, says the heavy rains cause challenges with the quality of water.
‘During heavy rains, the water turbidity – which is the clarity of the water – is high. In normal circumstances, the water’s turbidity lies between 30 and 50, but when it rains, the turbidity spikes to 350 because of the runoff soil and other material that rushes in with the water from the hills,’ he says.
Turbidity is the measure of the cloudiness or haziness of water caused by suspended particles like sediment, clay, algae, and organic matter. Tebandeke explains that turbidity makes it difficult and costly to treat the water.
‘When the turbidity is not high, we use about 10mg of aluminum sulphate to treat one litre of water. When turbidity is high during the heavy rains, we use between 30 and 50mg of aluminum sulphate per litre. The production capacity of this plant is 9,000 cubic metres of water per day, using 250kg of aluminum sulphate,’ he notes.
The expenses
The gravity of the matter is that by the time the water achieves the national standard, so much money has gone into treating it. For instance, in the dry season, the plant’s water filters are washed every 24 hours. However, during the rainy season, they become clogged with sand and have to be washed every three to four hours.
‘When the chemical quantity is high, we usually adopt other more expensive chemicals such as polymers, to ensure that we can till supply water,’ Tebandeke adds.
According to Innocent Twesigye, the principle engineer at NWSC, the corporation extracts water from River Nabijo, River Namatala, and River Nabuyonga in Mbale District. However, these upstream catchments are undergoing degradation due to human activity and a general increase in the population.
‘In the dry season, we have less water because it is diverted to people’s gardens upstream. During the wet season, the water is contaminated. Twenty years ago, we could pump 50 million liters of water per day, but overtime, the capacity of production is reducing due to environmental degradation,’ he says.
Twesigye adds that nowadays, in the dry season, it takes an whole day to collect and pump out 10,000 liters. Badiru Wandwasi, the former area NWSC manager, concurs that the corporation started registering discrepancies in water quality after the year 2000.
‘In Mbale City, accessing piped water in the dry season has become big challenge. Between February 20 and March 10 this year, we experienced a terrible situation where people would call, asking for water. They blamed NWSC but the reason was not inefficiency; the water sources had dried up overnight,’ he says.
Wandwasi reveals that NWSC used to extract five million liters a day from River Nabijo, three million liters from River Nabuyonga, and seven million liters from River Manafwa, to make the 15 million liters of water required to supply Mbale town per day.
‘In the dry season, River Nabijo gives less than two million liters and River Nabuyonga dropped to less than 1.5 liters per day. Now we rely on River Manafwa. To balance our supply, we rationed water supply between February and March this year. Downstream, people were struggling to get water for domestic use, while upstream, people were diverting water for there gardens,’ he says.
Solutions
To mitigate the problem, the Ministry of Water and Environment (MWE) and the National Water and Sewerage Corporation (NWSC) are jointly implementing the Integrated Water Management and Development Project (IWMDP).
The project is a World Bank-funded initiative aimed at improving water supply, sanitation services, and integrated water resource management in the catchment areas of River Nabijo, River Namatala, and River Nabuyonga in Mbale District.
The upstream buffer zones of the three rivers have been degraded due to human activity, with some farmers establishing gardens on the river banks. This has been blamed on the high population growth in the area, which has led to land fragmentation.
‘We are looking at environmental conservation, especially micro catchment restoration. We have done studies to understand what is happening upstream and the sources of pollution that are impacting our operational activities. We are spending a lot on chemicals and replacing our pumps because of siltation from the mountain,’ Twesigye says.
In 2022, a consultant carried out situational analyses and came up with a source protection plan to improve the situation upstream. The project that started in January this year is expected to end in January 2026 at a cost of Shs2.2billion.
‘We are looking at awareness and capacity building of stakeholders, carrying out civil works such as the construction of gabions on collapsed sections of the catchment area to control soil erosion from the mountain areas. We also intend to improve the livelihood of the residents. If people are benefiting from the buffer zones, they should be given an alternative source of living,’ Twesigye explains.
The plan also includes restoration activities such as planting trees within the buffer zones of the rivers, to minimise runoff during flash floods.
‘We are looking at 400 households to benefit from the 500 species of tree seedlings that we are going to supply. We hope to restore the 50 million liters we were extracting per day, and increase it to probably 100 million liters per day. If we do not do anything towards environmental conservation, within the next 15 to 20 years we will have no drop of water to supply to our customers,’ Twesigye adds.
Three development partners, including the International Union for Conservation of Nature (IUCN), are implementing the project for MWE and NWSC.
How floods affect water quality
Floods increase water treatment costs by damaging treatment plant equipment, requiring costly repairs and replacements of electrical components, pumps, and filters.
They also introduce high levels of contaminants like silt, bacteria, and chemicals, necessitating the use of more chemicals, increased labour for testing, and longer treatment processes to ensure water safety, all of which drive up operational expenses.
Infrastructure damage and repair
Equipment failure: Floodwaters can inundate and damage critical equipment like electrical switch gear, motor control centers, pumps, and valves, leading to corrosion and short circuits that render them inoperable.
Structural repairs: Prolonged exposure to floodwaters can weaken the foundations and walls of treatment plants, potentially requiring expensive structural repairs.
Replacement costs: Damaged or destroyed equipment must be replaced, which is a significant expense for municipalities.
Increased contamination and treatment needs
Higher contaminant levels: Floodwaters carry pollutants, debris, and sediments from sewage systems, agricultural fields, and waste sites into water sources.
Increased disinfection: The higher levels of harmful bacteria, viruses, and chemicals in the water require increased use of disinfectants, such as chlorine, to ensure the water is safe to drink.
Filter clogging: Elevated turbidity from silt and other contaminants can clog filters, pumps, and lines, requiring them to be cleaned or replaced more frequently.
Operational and labour costs
Extended treatment time: Water that bypasses or overwhelms the system requires more intensive and longer treatment processes to remove contaminants, increasing operational costs.
Labor for testing: After a flood, extensive testing of the water is required to meet regulatory standards and ensure it is safe for public use, which adds to labor costs.
Reliance on backup systems: Damage may force a plant to rely on backup facilities, which can strain resources and further increase costs.
Emergency response: Communities may have to rely on bottled water and emergency supplies, and fund emergency response efforts, increasing overall costs.