Built between 1945 and 1948,[2] the reservoir covers an area of 52.9 hectares and has a capacity of 4.6 million cubic metres.

The dam is located at Paruroa, near the site of the military base of the Te Taoū hapū (subtribe) of Ngāti Whātua, who were warring with Te Waiohua, the dominant force in Tāmaki Makaurau in the early 18th century.

[3][4] Years of conflict culminated in the early 1740s, when Kiwi Tāmaki, the ariki of Waiohua, was defeated at Paruroa, leading to Ngāti Whātua becoming the main political force on Tāmaki Makaurau.

[3][4] Te-Rangi-hinganga-tahi, the final battle between the two forces, took place around the reservoir and Parau to the south.

[6] The Lower Nihotupu project became urgent due to the very dry summer of 1942/3, as well as increased water use by the United States Armed Forces personnel stationed in Auckland during World War II.