Lesotho Highlands Water Project Phase II

Project Overview

Phase II of the Lesotho Highlands Water Project (LHWP) is a bi-national water resources project initiative between the Governments of Lesotho and South Africa. The Polihali Transfer Tunnel will convey water from Polihali Reservoir to Katse Dam. The works will include an intake at the new Polihali Reservoir, a 5 m diameter and 38.5-km-long fully concrete lined water transfer tunnel, gate shafts, access adits, and outlet works at Katse Dam. The outlet works will terminate in a Norwegian type lake tap that will be excavated by blasting inside the Katse Dam impoundment on the eastern flank of the existing reservoir.

Knight Piésold is part of the Metsi a Senqu-Khubelu Consultants (MSKC) joint venture with Aurecon, Hatch, SMEC, and FM Associates. The Polihali Transfer Tunnel appointment is MSKC’s second appointment on Phase II, with the MSKC also having been appointed for the “Design and Construction Supervision of the Polihali Diversion Tunnels” in September 2016. This was for the design and construction supervision of two diversion tunnels to facilitate river diversion during construction of the Polihali Dam, comprising a 7 m and 9 m diameter tunnel with lengths of 910 m and 960 m, respectively.

Project Role

Lead engineers responsible for preliminary and detailed design and construction monitoring services for all civil/structural works components and cast in-situ concrete lining design, including optimising the scheme components, production of final designs for the works, and onsite construction monitoring for quality assurance.

Engineering services include:

• Project optimisation
• Detailed design
• Procurement
• Construction monitoring and quality control
• Commissioning