Lake Taupo, in the centre of the North Island, is the largest lake in New Zealand, with an area of 250 sq. miles. The eastern stretch extends for 25 miles from Taupo to Tokaanu, and Western Bay is a large semicircular extension towards the north-west, bounded by vertical rock cliffs. South of Western Bay the lake is from 300 to 360 ft deep, but in the bay it is 60 ft deeper, and extending east is a trough reaching a maximum depth of 522 ft, 3 ½ miles west of Waitahanui.
Lake Taupo occupies an area of volcanic subsidence, Western Bay being part of a large caldera. After the latest great pumice eruptions about 1,850 years ago, the outlet was blocked and the lake rose temporarily for 110 ft leaving a bench at this level. It was named by the early Maori inhabitants after the rocky cliffs behind Halletts Bay. The first European to see Lake Taupo was the Rev. Thomas Chapman, in 1836.
The largest stream entering the lake is the Tongariro River, which has built a delta between Turangi and Tokaanu. The total drainage basin is 1,400 sq. miles, and the Waikato River, which flows out of the north-east end of the lake, is the largest in the North Island. Gates at the outlet point control the level of the lake to within 5 ft of 1,172 ft above sea level and regulate the flow down the river to seven hydro-electric stations.
Taupo is an important holiday centre, boating, swimming, and trout fishing being the most popular sports. There are hot springs at Waihi, Tokaanu, Motuoapa, and Taupo, and hot mineral baths at Tokaanu and Taupo. The Auckland-Wellington Highway skirts the eastern shore.
by James Healy, M.SC., Volcanologist, New Zealand Geological Survey, Rotorua.