Mwambashi stream

Mwambashi Stream is a seasonal tributary of the Kafue River, flowing through the Copperbelt Province of Zambia—particularly through Kalulushi and Kitwe—before merging with the Kafue south of Kitwe. The stream supports irrigation, domestic use and local ecosystems.

Mwambashi Stream
Main source	Chambishi
River mouth	Kafue River, near Kitwe
River system	Zambezi Basin
Length	Seasonal

Geography and hydrology

Mwambashi originates near Chambishi and travels southwest through Kalulushi, where it feeds into the Kafue River. While largely seasonal, it maintains baseflow during the dry season and is a key water source for communities and agriculture.

Ecological and human importance

The stream supports subsistence farming (maize, groundnuts, vegetables), small-scale fisheries, and provides domestic water for tens of thousands of people. It also sustains local ecosystems—fish, birdlife and riparian vegetation.

2025 acid spill crisis

In mid-February 2025, a tailings dam failure at Sino‑Metals Leach Zambia in Chambishi released highly acidic and metal-contaminated effluent into Mwambashi, with widespread environmental and social consequences.

Contamination and impact

<pH levels dropped to as low as 1 near Chambishi and remained dangerously low (<3) at treatment plants in Kitwe. The spill led to mass fish kills, destruction of crops in Kalusale and surrounding farms, and suspensions of water supplies in Kitwe and Kalulushi. Farmers saw their livelihoods wiped out:

Government and corporate response

• Operations at Sino‑Metals and related facilities were suspended; Nkana Water halted abstraction from Mwambashi.
• Zambia Air Force dropped lime from helicopters; WARMA, ZEMA, Nkana Water, and other agencies mobilised to neutralise acidity.
• pH levels later rebounded to near-neutral (6.9 – 7.4); heavy metals (copper, manganese, zinc) remain elevated.
• Government launched an independent investigation to assess damage, dam integrity, and recommend preventive measures.
• Nkana Water stepped up water bowsers and hourly monitoring; committees were formed to register affected farmers for compensation.
• WWF Zambia called for a nationwide audit of tailings dams to prevent future disasters.

Public health advisory

On 23 February, Fisheries and Livestock Ministry warned against consuming fish from Mwambashi and Kafue due to heavy-metal contamination.

Aftermath and ongoing concerns

While acidity has largely been neutralised, heavy-metal contamination persists in sediments and groundwater. Remediation continues, but fears remain of long-term environmental and health impacts.

The incident prompted public demands for accountability, stronger enforcement of environmental laws and improvements in dam safety protocols across Zambia.

See also

• Kafue River
• 2025 Zambia acid spill
• Mining in Zambia
• Environmental disasters in Zambia