By Charles Mkoka and Mecklina Chirwa:
(A continuation from yesterday’s Malawi News)
In recognition of the fact that Lilongwe River plays a key role in the supply of water to the city’s resident, Lilongwe Water Board (LWB) devised a river management plan that, among other things, highlighted that uncontrolled development has resulted in proliferation of structures that are not in tandem with water supply. The plan suggested a need to regulate infrastructure development activities that take place within the river’s catchment area. It further warned that all polluting developments should be relocated unless realistic and effective management measures can be put in place and implemented.
The plan also raised concerns that expansion of locations such as Chinsapo, Chigwirizano and Likuni high-density residential areas has seen the opening up of a graveyard, about a kilometre or less from Lilongwe River.
In terms of river bank management, the Water Resources Act of 1988 and the Lilongwe Catchment Control Order 1999 requires maintenance of a 50-meter buffer zone for streams and a 100-meter buffer zone for all water reservoirs. Maintenance of such a zone will ensure reduction in water quality deterioration, reduction in siltation and the maintenance of a healthy riverine ecosystem. Enforcement of the buffer zone will deter sand miners and brick makers from encroaching the riverbanks.
Impact of degradation on water quality and treatment
In order to make raw water safe it goes through the following processes. Once collected, it is first screened at the water intake-points to remove debris and large objects. Then natural settlement of suspended matter; this occurs in the raw water reservoir before any chemical treatment process. Then the water goes through a process that involves addition of a chemical that destabilise suspended matters in raw water, causing mud balls which later settle down in the sedimentation tanks.
Later filtration that traps off tiny particles by filter media composed of various sizes of sand that is properly arranged with coarse sand at the bottom of the filter tank. Finally, disinfection using chlorine is done to kill all microorganisms such as harmful bacteria, viruses or intestinal parasites as the final process of water treatment.
Maxwell Ngochera, water quality specialist and a freshwater scientist with the Fisheries Research Unit at Monkey – Bay explained that the implications of silt loading into the dams lead to excessive accumulation of mud.
“To maintain water volumes, dredging will be required which is not cheap. It also means water will have a lot of dissolved solvents resulting in high costs for filtration. In addition, siltation will also mask nests and potential breeding areas for available aquatic life in the dam such as fish,” Ngochera narrated.
He warned that all these activities have operational as well as economic cost on water supply in addition to posing health risks to both humans as well as aquatic animals.
Wisdom Changadeya, lecturer in fresh water biology at the University of Malawi’s Chancellor College concurred with Ngochera, saying increased silt would increase cost of chemicals and processes.
According to Changadeya, water quality is directly linked to activities in the catchment area. With degradation of a catchment area comes increased level of nutrients such nitrates, phosphates and other elements such as iron. These are transported by run-off from the catchment onto the dams since nitrates would dissolve in the runoff water while phosphates would be attached to silt particles.
“Increased levels of these elements would imply that the board’s standards for these elements are exceeded making the water not fit for human consumption in accordance with Malawi Bureau of Standards and World Health Organization. In this regard the board would incur additional expenses to treat the water so as to meet required standards for human consumption.” Changadeya, who lectures students in fresh water biology, observed.
In the worse scenario, Changadeya further added, when the levels of phosphates, nitrates and other elements are too high, the dams would experience rapid proliferation of algae and other water plants such as water lilies, water hyacinth which could clog up the water treatment facilities and also cover water bodies like the case of water hyacinth (Namasupuni). Clearing and removing of plant material from the treatment facilities and the dams would increase expenditure of the board.
Human induced degradation and indiscriminate disposal of wastes along the Lilongwe River course has increased water treatment costs due to silt and dissolved solvents. On average, the board is spending about 1 billion Kwacha annually on water treatment, according to available data.
More awareness and youth involvement
Malingunde Trading Centre where the two reservoir dams are located in Traditional Authority Masumbankhunda’s area where rural youths under the Malawi Youth Forest Restoration Programme are also involved in raising tree seedlings. This is spearheaded by the local government, an initiative launched in 2018 aimed at economically empowering young people in exchange for managing tree seedlings planted in their localities.
“In the year 2018, our village headman called for a meeting to sensitize the youth on this programme. We then formed youth groups and things turned out even better for us. I was chosen coordinator of all youth groups in this area,” a smiling Charles Jekete, one of the youth leaders in the afforestation drive in the area, explained.
“Our task is to plant tree seedlings in degraded areas and manage them to grow in our own villages as part of ecosystem restoration. This has an economic activity attached to it among the youth as part of job creation,” he said.
According to National Statistical Office findings in 2015, Malawi has a youthful population. Among the 17.2 million people, 64 percent are under the age of 24. Despite the productivity potential of the 18-35 years age group, they are largely unemployed.
Part of the effort to tackle youth unemployment while restoring degraded areas
The activities involved include land preparation, digging of holes, actual tree planting, pruning, weeding and construction of fire break including water conservation says Principal Forestry Officer, Tangu Tumeo who coordinates the initiative at forestry department.
The youth efforts compliment the Office of the President and Cabinet efforts in securing Dzalanyama Forest Reserve watershed.
BOX 1 – QUICK FACTS
- Lilongwe Water Board (LWB) is a Statutory Corporation established in 1947 and reconstituted by the Act of Parliament ‘Water Works Act’ No. 17 of 1995.
- LWB’s mandate is to manage the source of raw water, abstract and treat water in full compliance with regulatory bodies such as World Health Organization and Malawi Bureau of Standards and provide adequate and reliable water supply to the residents of the City of Lilongwe that meets customer needs.
- Lilongwe Water Board was awarded jurisdiction to supply water to an area of about 45,000 hectares. The supply area is currently demarcated into three zones namely: Northern; Central; and Southern Zone.
- The Board abstracts its raw water from Lilongwe River which originates from Dzalanyama Ranges. There are two dams constructed along the river; Kamuzu Dam I and Kamuzu Dam II. The catchment area is approximately 1,870 square Kilometers.
- Kamuzu Dam I was constructed in 1966 and has a storage capacity of 4.5 million cubic meters, Kamuzu Dam II was constructed in 1989 with an initial storage capacity of 9.2 million cubic meters. The Dam was rehabilitated and raised in 1999 thus increasing the storage capacity to 19.8 million cubic meters. Kamuzu Dam I act as a balancing reservoir and its outflow goes directly into Kamuzu Dam II. Water flows by gravity down to the abstraction point, about 20 km downstream.
- The Board has two main Treatment Plants, TW I and TW II which are situated within the Water Works Campus, off Likuni Road in Area 3. The combined capacity of the two plants is about 125,000 cubic meters per day.
- Lilongwe City has a population of about 1.2 million and the Board currently serves around 83% of the population. There are about 83,000 metered customers and more than 1000 water Kiosks (communal water selling points) within the City.—Lilongwe Water Board website