[2][4] The area is of immense cultural, spiritual, economic, and traditional significance to the local iwi, Ngāti Porou, and in 2002 approximately 90% of its 2,000 inhabitants were Māori.

There was a small area to the east of the river covered in coastal forest and scrub due to partial clearance and burning.

Floods and heavy rainfall are common to the area, and this, combined with the development, resulted in widespread erosion and large amounts of sediment being deposited in the Waiapu River and its tributaries.

[2] Gravel deposited by the river onto shingle beaches near its mouth is extracted at approximately 12 different sites, predominantly for use on nearby rural and forestry roads.

[12][14] The water quality of the river's tributaries is often much higher, as they are closer to the native vegetation cover of the Raukumura Range.

[1][2][5] Mount Hikurangi is the iwi's most important icon, and in Māori mythology, was the first part of the North Island to emerge when Māui, an ancestor of Ngāti Porou, pulled it as a giant fish from the ocean.

According to myth, Paikea's younger half-brother, Ruatapu, attempted to kill about 70 of his older kin ("brothers") at sea in Hawaiki to exact revenge on his father for belittling him as a low-born son of a slave.

[1][2][5] According to traditional beliefs, they have had an undisturbed relationship with the river since the time of Māui, which serves to unite those who live on either side of it.

[2] The valley was a place where they could live, offering safe refuge during periods of war, and supplies of fresh water and various species of fish.

[21][22] The previous decade, Taumata-a-Kura of Ngāti Porou had been captured by a Ngāpuhi war party, and been made their slave in the Bay of Islands.

[1][23] In 2002, the valley's population was approximately 90% Māori, and traditional culture is still practised in the area — though it has changed significantly in the last 150 years.

A local tohunga, George Gage (Hori Te Kou-o-rehua Keeti) was approached to help the situation, and after that there were no similar drownings.

[19] The deforestation and land development of the area, largely planned and managed by non-Maori groups, have had a huge negative impact on Māori.

[2] In December 2010, Ngāti Porou signed a settlement deal with the New Zealand Government for various grievances, some of which relate to the Waiapu Valley.

[1][17] The settlement included a NZ$110 million financial redress, and the return of sites culturally significant to the iwi totally approximately 5,898 hectares (14,570 acres).

In 1875 “Scotty” Siddons, mate of the Beautiful Star, claimed to have met, on the East Coast, a Māori who had a few ounces of gold.

He and a mate named Hill found a lot of mundic on the north-west side of the mountain, but only outcrops of limestone on the higher slopes.

Drays, wheelbarrows and receptacles of all kinds were rushed to the scene, and large quantities of the “precious metal” were removed to a safe place.

When it turned out that the metal was only mundic, Reupane became an object of ridicule, and, afterwards, was known as “Tommy Poorfellow.”[20] The area was home to politician Sir Āpirana Ngata, and Te Moananui-a-Kiwa Ngārimu — the second of three Māori to receive a Victoria Cross.