There are 20 lakes within 20 miles of Rotorua, though some are small and not well known. All are of volcanic origin, filling craters, calderas, or valleys blocked by lava flows.

Lake Rotorua is circular, 6 miles in diameter, and slopes gently down to the deepest part west of Mokoia Island. It occupies a caldera, and a bench 300 ft above the lake marks its original level. Tapsell in 1830 was probably the first European to seethe lake, but in 1831 Henry Williams and Thomas Chapman came through the district, and in 1835 the latter established a mission station on Mokoia. Well known for the hot springs of Whakarewarewa, Kuirau, and Ohinemutu, and the cold springs of Hamurana, Rainbow, and Fairy, the lake is a popular tourist resort for yachting, fishing, and swimming. The city of Rotorua is on the south shore. The Ohau channel flows out at the north-east end into Rotoiti.

Rotoiti is 8½ miles long by less than 2 miles wide, and the deepest point is near the centre. The lake is a popular fishing and boating resort and hot-spring baths at Manupirua are accessible by boat on the south shore. The Kaituna River flows out at Okere. Rotoiti, Rotoehu, and Rotoma lie along the northern rim of a large caldera, cut off by big lava flows on the south side. The cliffs on the north of Rotoiti and along Hongi's Track form part of the caldera wall. Rotoehu has hot soda-spring baths at the south-east end, and Rotoma is a popular picnic and boating resort. Neither lake has any outlet.

Lake Okataina also lies between the caldera wall and Haroharo lava flows, its steep bush-clad slopes giving it great scenic beauty. Lake Tarawera is a broad, branching lake with fairly flat floor filling a valley between Haroharo and Tarawera lava flows over which the Kaituna flows out to the east. Rotomahana occupies craters formed by steam-blast eruptions which accompanied the Tarawera eruption of 1886 and which destroyed the famous Pink and White Terraces and the earlier Lakes Rotomahana and Rotomakiriri. The eruption debris blocked the valley leading to Lake Tarawera. The round trip for tourists crosses Rotomahana and Tarawera Lakes by boat.

Okareka, Rotokakahi (Green Lake), and Tikitapu (Blue Lake) are lakes of scenic beauty nestling among steep hills, and the last is a crater from which the coarse pumice quarried near Rotorua was erupted. Rotokawau, Roto Ngata, and Roto Atua are small crater lakes, and a number of small lakes at Waiotapu, some of them warm, occupy craters formed by steam-blast eruptions.

*North of Sulphur Point is an isolated spot with a depth of 120ft. Possibly this is a small crater.

by James Healy, M.SC., Volcanologist, New Zealand Geological Survey, Rotorua.