JACK ZIMBA, Lusaka
THE Zambezi River may have given Zambia its name and gifted it with the majestic beauty, the Victoria Falls, but it is the Kafue River that gives the country its life, running through it like an artery.
As Kafue River flows from Kipushi on the border with the Democratic Republic of Congo through the country’s four provinces – North-Western, Copperbelt, Lusaka and Southern provinces, it supports urban life, industries, mines and agriculture.
And as it flows in the central and southern regions, it gives birth to some of the country’s richest biodiversity and ecosystems – Kafue National Park, the Lukanga Swamps and the Kafue Flats.
Further downriver, Kafue is dammed to produce about 50 percent of the country’s electricity at Itezhi-Tezhi and Kafue Gorge power stations.
In Southern Province, the river waters over 61,000 hectares (ha) of farmland, including about 1,600ha of sugar cane plantations owned by the Nakambala Sugar Estates.
It also supports about 20 percent of the country’s cattle population across the grassy plains of Namwala, and accounts for seven percent of the fish consumed in Lusaka.
Three water utilities get their water directly from the Kafue River to supply thousands of homes.
About half of Lusaka’s three million-plus residents get their water supply from the Kafue River through the Lusaka Water and Sewerage Company.
The Kafue catchment, an area that covers approximately 156,034km2 (about 20 percent of Zambia’s total land area), supports 1,296,685 households, representing 52 percent of all the country’s households, or about 6.6 million of the population.
But all this economic and social benefit comes at a huge cost to the river. As the Kafue flows through the Copperbelt region, it picks up a myriad of impurities from industries, mines and commercial farmlands.
The quality of water in Kafue River has been a case of various studies as well as legal battles for a long time.
Studies by the Zambia Environmental Management Agency (ZEMA) have found the most concentration of impurities in the river between Chingola and Kitwe.
On a map by ZEMA, the Kafue between Chingola and Kitwe is indicated in red. The red indicates high pollution.
Some of the biggest culprits in terms of pollution have been the mining companies.
In 2011, the High Court found Kansanshi Copper Mines guilty of polluting the Mushishima River, a tributary of Kafue River, and poisoning 2,000 people.
After a long court battle, the Supreme Court in 2015 upheld that decision.
The pollution of Kafue River poses a huge challenge for water utilities to make their water safe for drinking.
According to Nkana Water and Sewerage Company (NWSC) public relations manager Bivan Saluseki, the problem is more pronounced in the dry season.
“In the dry season we have a problem with impurities from mine effluent which mostly is very high sulphate levels from mine process effluent water which ends up in the rivers,” says Mr Saluseki.
He adds: “Mine effluents are a challenge to NWSC because our old plants are not designed to remove mine water pollutants.”
When the pollution levels in the river reach unacceptable levels, the water utility is forced to shut down its plants, thereby depriving many households water.
“Water treatment operations in itself is an expensive undertaking. Huge amounts of chemicals are used in treating water to a level of safe drinking water quality. The more impurities the raw water may contain, the higher the cost of treatment, in that large amounts of water treatment chemicals such as aluminum sulphate and chlorine have to be used to treat this water,” says Mr Saluseki.
As the river passes though Lukanga Swamps in Central Province, the wetlands function as a sink for pollutants, cleansing the polluted river, according to ecologist Chaona Phiri.
But this cleansing of the Kafue means that the Lukanga Swamps have high concentration of chemicals, giving rise to another problem – the Kariba weed.
The Kariba weed is an invasive plant that now threatens this ecosystem. The weed is native to South America and was first noticed on Zambezi River near Kariba Dam. With no natural enemy, the plant spreads uncontrollably.
And in the Lukanga Swamps, the weed has enough nutrients to thrive.
“If our waters didn’t have a very high heavy metal content, the weed wouldn’t have thrived. It thrives especially in areas that have high concentration of sodium, potassium and manganese,” says Ms Phiri.
As the weed spreads and blankets the swamp, it cuts off the oxygen supply, affecting marine life, according to Ms Phiri, who works for Birdlife Zambia and has worked in the Lukanga Swamps before, researching on birdlife.
She says the invasion of the swamps by the Kariba weed has resulted in loss of habitat for many bird species.
According to Ms Phiri, the swamps are usually home to about 300 bird species – both resident and migratory – but one recent study showed that only 105 species remained in the swamps.
The Lukanga swamps are designated as one of the most important bird areas.
But the presence of the weed also means small catches for the fishermen who rely on the swamps for the supply of fish, which they sell to places like the Copperbelt.
“Having that weed on the water means that the amount of oxygen in the water is reduced, and the amount of light penetrating the water is reduced, meaning that food for fish is reduced; fish don’t like such areas except in the breading season,” she says.
A 2017 report by the Worldwide Fund for Nature says “Elevated concentrations of nitrogen and phosphorus in the water resource are a risk because the nutrients act as fertilisers, causing excessive growth of algae and other aquatic plants. In turn, excessive algae blocks out light, which inhibits the growth of other plants. When the algae dies and decays, it uses large portions of available oxygen in the water body, causing oxygen levels to become very low. This process of nutrient enrichment is called eutrophication, and the oxygen depletion that accompanies often results in the suffocation and death of fish and other aquatic life.”
According to Ms Phiri, records by the Fisheries Department show a huge reduction in fish catches.
“Fishermen have to set their nets for much longer in order to make a small catch,” she says.
So why has the pollution of the Kafue gone on for so many years?
Hydrologist Michael Kambole thinks the law is not punitive enough to stop the big pollutants, such as the mines.
“I do not think authorities have failed to deal with the mines in as far as pollution is concerned. What is very sad, however, is the wrong perception that has been created that seems to suggest that it is cheaper to pollute the environment than to prevent pollution from occurring. I believe our punitive measures are not deterrent enough to prevent industries from polluting at will. Furthermore, authorities have failed to force industries to implement plans and measures to effectively monitor pollution,” he says.
Mr Kambole, in a research in 2003, notes that the survival of the Kafue River Basin ecological system and biodiversity depends on the extent to which the degradation and pollution controlled.
Many years after Mr Kambole’s research, little has changed.
He suggests that waste emission rates should equal the natural assimilative capacities of the ecosystems into which the wastes are emitted.