The Ōhinemahuta (Onamalutu) River is a small tributary of the Wairau 28km from Blenheim which drains from the schist mountains of the Richmond Range . Before the arrival of European sawmillers the valley was densely forested in mixed broadleaf and podocarp forest. Because of the narrow entrance and towering forest Maori explorers aptly named it Onamahutu, place of the cave. Now, many years on almost all of the river flats have been cleared of bush for timber and farming. Onamalutu has become popular with small holders while the remaining land is used for dairying and exotic forestry. The only remaining native forest left is a small stand of virgin kahikatea forest near the head of the valley. In 1901 after three quarters of the forest had been removed, sawmiller Charles White offered to exchange the reserve area for other land so that it might be used as a picnic ground for Blenheim towns people. The offer was accepted and the now 26 hectares of land is a popular visiting place for people throughout Marlborough.