Lake Rotoiti is the smaller of the two large glacial lakes in Nelson Lakes national park. The lakes were formed when rivers were dammed behind past glaciers’ terminal moraines (ridges of rubble that form at the front of a glacier) (source www.teara.govt.nz).
Lake Moawhitu is located on Rangitoto ki te Tonga, also known as d’Urville Island. The lake was once an important source of mahinga kai, in particular tuna (eel), for the local iwi Ngāti Koata. Over the past decades the health of lake has declined.