South Africa and Lesotho have officially launched the second phase of a massive water transfer project, their biggest joint infrastructure investment to date.

Work on the 14-billion-rand ($1.3-billion, 950-million-euro) second phase of the Lesotho Highlands Water Project is expected get underway next month with the construction of a 155-metre (508-foot) high Polihali Dam and tunnels.

South Africa’s President Jacob Zuma called it a “win-win” project, as impoverished Lesotho will secure revenue while South Africa gets water. Launched in 1998, the project provides South Africa with the scarce resource, while contributing to the economic growth of the tiny mountainous kingdom, known for its large water reserves.

The project situated in the northern part of the country is expected to be fully operational in 2022. Lesotho has benefited from significant infrastructure development since the inception of the scheme, including road linkages and upgrades. The landlocked country, entirely surrounded by South Africa, also generates hydro-power from the large dams built so far.