the Mangahao-Waikeremoana system and on to the lower North Island. In 1934, increasing demand for electricity resulted in Arapuni being extended. The powerhouse was doubled in size, and provisions for four more turbines were made. Turbines 5 and 6 were commissioned four years later in 1938. The last two turbines were commissioned in 1946 to meet the increasing demand for electricity following World War II. In 1990, a $50 million repair, refurbishment and upgrade project was completed, the first stage of which involved construction of a diversion channel. In 2000 it was determined that the historic seepage problem had worsened, interim repairs were carried out while a more permanent solution was devised and this took the form of a $20 million engineering project, which was carried out in 2005–07. In 2001, work was completed on four of Arapuni's turbines to increase capacity from to each and to improve their peak efficiency. References Further reading External links Energy infrastructure completed in 1929 Energy infrastructure completed in 1932 Energy infrastructure completed in 1938 Energy infrastructure completed in 1946 Hydroelectric power stations in New Zealand Buildings and structures in Waikato Heritage New Zealand Category 1 historic places in Waikato 1920s architecture in New Zealand