Bulawayo dams under threat
The Chronicle
27/8/2021
Mashudu Netsianda, Senior Reporter
AS the sun recedes slowly beneath the horizon with the light blue sky melting into darkness, silhouettes of men walking along the dam wall at Upper Ncema while carrying picks and shovels on their shoulders, reflect across the surface of the water.
Clad in dirty overalls and tattered clothes, they trudge through the winding pathways and hills past ominous pits of muddy water as they trek back to their respective homes after a long day in the bush digging up riverbanks in search of alluvial gold deposits.
From dusk until dawn, they will be involved in illegal gold panning activities around Bulawayo’s water catchment areas at Inyankuni, Upper and Lower Ncema dams in Esigodini under Umzingwane District in Matabeleland South.
Popularly known as “amakorokoza”, the gold panners have ramped up their illegal activity in the city’s catchment areas posing a serious threat to Bulawayo’s water supplies.
Matabeleland South Province is known for numerous gold deposits which lure people from across the country.
Gold panning activities are also causing siltation, an accumulation of fine soil that is blamed for diminishing water supplies in the dams that serve the city.
A recent visit to the affected areas revealed that a lot of alluvial gold panning activities take place on the river beds and banks of the Umzingwane and Mtshabezi.
A large proportion of the catchment area for Bulawayo’s water supply dams falls within this area. Major dams such as Umzingwane, Upper Ncema, Lower Ncema, Inyankuni and Mtshabezi are under threat due to a spike in illegal gold panning. The local community, the Zimbabwe National Water Authority (Zinwa) and the Bulawayo City Council (BCC) are the worst affected by the illegal gold panning activities, which cause land degradation and siltation of dams.
The Environmental Management Agency (Ema)’s provincial manager for Matabeleland South Mr Decent Ndlovu said gold panning processes on the river banks, beds and the surrounding areas discharge huge amounts of loose silt and heavy metals into the river system.
“As Ema we are extremely worried about these illegal gold mining activities happening on the river banks and water catchment areas. Gold panning has devastating impacts on the environment such as deforestation as they burn bushes and use harmful chemicals like mercury,” he said.
“These environmental impacts are a result of destructive mining, wasteful mineral extraction and processing practices and techniques used by the illegal gold panners.”
Mr Ndlovu said the mercury used by panners is discharged into ecosystems in an abusive manner.
“Eventually these contaminations are washed into the dams, increasing the risk of siltation, flooding and drying up of water reservoirs. Land degradation also results in the loss of aesthetic value of the landscape as mining activities leave open pits and mounds of sand,” he said.
According to scientific studies, mercury is detrimental to human health, linking exposure to the element to skin disease, infertility and birth defects.
When inhaled, the chemical can also cause lung cancer.
Mercury is used for gold amalgamation in artisanal mining. According to a recent United Nations Environment Programme (UNEP) report, the amalgamation process transforms elemental mercury into methyl mercury. Methyl mercury, one of the most toxic organic compounds, is a powerful neurotoxin that works its way up the food chain through bioaccumulation. This poses a threat to the health of animals, humans and aquatic life.
According to the Food and Agriculture Organisation (FAO), the total capacity of the 2 168 dams in the Zimbabwean part of the Limpopo basin, of which Umzingwane, Upper Ncema, Lower Ncema, Inyankuni and Mtshabezi dams are a part, has fallen by about 29 million cubic metres as a result of siltation.
Bulawayo has in the past few years been worst hit by water shortages due reduced storage capacity of the dams supplying water to the city, forcing the council to introduce a 144-hour water shedding programme a few months ago.
Bulawayo”s water consumption is 155 megalitres (ML) per day and 58 percent of that comes from the Umzingwane catchment area. Zinwa said the river system has been negatively affected by gold panning. The drying up of dams and rivers in Umzingwane District has been blamed largely on siltation.
Zinwa corporate communications and marketing manager Mrs Marjorie Munyonga said they were worried about the levels of siltation in the country’s rivers and dams. “Siltation is really a cause for concern to us as a national water authority. The country’s major rivers are heavily silted and it greatly affects water yields and water holding capacity of our water bodies and compromises the country’s water security,” she said.
Mrs Munyonga said the major cause of siltation could be attributed to land degradation due to anthropogenic activities such as gold panning and poor environmental practices.
She said once the water is contaminated with cyanide or mercury, it means more costs for Zinwa and BCC to treat it.
“Chemicals such as cyanide and mercury affect humans and farming practices. If the water is supposed to be used for drinking, is means as Zinwa or local authorities will need more chemicals to treat that water so that it meets the required standards,” said Mrs Munyonga.
“This is an issue of major concern and we are working hand in hand with local authorities and Ema to make sure that we address this issue because it is an expensive process for us as Zinwa to be able to treat that water.”
Mrs Munyonga said strategies to minimise siltation including integrated river basin management and sustainable land use approaches are being pursued to combat the problem.
“Efforts are being made to de-silt the dams and rivers. De-silting is done after an analysis is carried out to determine the extent of the siltation and the attendant costs of removing the silt. All the major rivers have been affected by siltation and Zinwa is working closely with stakeholder organisations such as the catchment and sub-catchment councils to ensure that siltation is minimised,” she said.
BCC corporate communications officer, Ms Bongiwe Ngwenya said the worst affected catchment areas are Ncema, Inyankuni and Umzingwane dams because of their alluvial gold deposits. Original water holding capacity for Insiza Dam is 173,49 million cubic metres, Inyankuni 80,8 million cubic metres, Lower Ncema 18,2 million cubic metres, Umzingwane 44,7 million cubic metres and Upper Ncema 45,4 million cubic metres.
Miss Bongiwe Ngwenya
However, the dams’ water holding capacities have since been drastically reduced due to rampant siltation.
Ms Ngwenya said rangers and police are struggling to effectively conduct routine patrols in the affected areas due to inadequate resources.
“Routine patrols are ongoing at our water catchment areas. However, the main challenge we are facing revolves around limited human resources and vehicles,” said Ms Ngwenya. She said in most cases, the illegal gold panners would be armed with dangerous weapons. In May, 23 illegal gold panners were arrested bringing to 229 the total number of illegal gold panners arrested since the beginning of the year.
Following their arrest, police recovered several tools, which included crowbars, detectors and shovels.-@mashnets.