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Lesotho Highlands Water Project Phase 2 (Polihali Dam & Tunnel)

Country
Lesotho; South Africa
Sector
Infrastructure
Intelligence Type
Project
Status / Stage
Under Construction
Estimated Value
USD Billion (Phase 2 estimate) 3.5
Confidence
Confirmed

The Lesotho Highlands Water Project Phase 2 is one of the largest water infrastructure projects in Southern Africa, consisting of the Polihali Dam on the Senqu River and a 38km transfer tunnel connecting the Polihali Reservoir to the Katse Dam (Phase 1 infrastructure). The project delivers water to South Africa’s Gauteng province (population ~16 million) and generates hydropower for Lesotho. The Polihali Dam is under active construction. The project is jointly managed by the Trans-Caledon Tunnel Authority (TCTA) of South Africa and the Lesotho Highlands Development Authority (LHDA).

Project Details

Project TypeRockfill dam (Polihali), transfer tunnel (38km), hydropower plant
Project OwnerLesotho Highlands Development Authority (LHDA); Trans-Caledon Tunnel Authority (TCTA), South Africa
Project SponsorGovernments of Lesotho and South Africa — Treaty obligation under the 1986 LHWP Treaty
Start Date2020 (Phase 2 construction commencement)
Expected CompletionPolihali Dam: 2027-2028; Transfer tunnel: 2028-2029
Current PhaseConstruction
Funding StatusPartial

Key Issues / Risks

South Africa's ongoing water scarcity crisis in Gauteng makes delivery timeline critical. The tunnelling component is technically complex — 38km through mountain terrain. Cost overruns on Phase 1 (completed 1996) are a precedent risk.

Latest Development (Detail)

Polihali Dam under active construction; tunnel boring has commenced. The project is proceeding under strong bilateral political support from both governments given Gauteng's water supply urgency.

What Happens Next

Completion of tunnel boring; Polihali Dam wall reaching design crest level (2027-2028 window).

Commercial Opportunity

A $3.5bn construction programme in a landlocked Southern African country — significant for civil and dam engineering contractors, tunnel boring specialists and water infrastructure consultants.

Stakeholder Intelligence

Key Organizations / Companies InvolvedDevelopment Bank of Southern Africa (DBSA); African Development Bank; European Investment Bank; Agence Française de Développement; South African and Lesotho treasury contributions

Commercial Opportunity Intelligence

Potential BeneficiariesSouth African water utilities (Rand Water); Lesotho hydropower consumers; dam and tunnel engineering contractors; water infrastructure consultants
Opportunity SignalDirect link to South Africa's Gauteng water security — the most politically and commercially significant water project in Southern Africa right now.
Commercial ReadinessCommercially Active

Source & Verification Trail

Last VerifiedAugust 2026
Source(s)LHDA official project updates; TCTA annual reports; AfDB project documentation; Development Bank of Southern Africa
Source Date2025–2026