Waiapu River facts for kids

The Waiapu River is a long river located in the Gisborne District of New Zealand's North Island. It stretches for about 130 kilometers (81 miles). This important river flows through the north-east part of the Waiapu Valley.

The Waiapu River starts where the Mata River and the Tapuaeroa River meet. Both of these rivers come from the Raukumara Range mountains. The Waiapu River then flows past the town of Ruatoria before it reaches the Pacific Ocean at Rangitukia. Other smaller rivers and streams, called tributaries, also join the Waiapu River. These include the Mangaoporo, Poroporo, Wairoa, Maraehara rivers, and the Paoaruku stream.

The Waiapu River is very well known in its area. It is located within the traditional lands, or rohe, of Ngāti Porou. Ngāti Porou is a large iwi (tribe or kinship group) on the East Coast of New Zealand. The name "Waiapu" means "swallowing river" in the Māori language.

Why is the Waiapu River important?

Changes to the Waiapu Valley Environment

A long time ago, around 1840, most of the land around the Waiapu River was covered in native forest. About 80% of the area, which is 1,734 square kilometers (669 square miles), had many different native plants and animals. There was also some coastal forest and scrub near the river.

However, between 1890 and 1930, a lot of this native forest was cut down and burned. This was done to create land for pastoralism, which means raising animals like sheep or cattle. The Waiapu Valley often has floods and heavy rain. When the forests were removed, the soil was no longer held in place by tree roots. This led to a lot of erosion. Huge amounts of sediment (like mud and gravel) were washed into the river. This changed the landscape a lot.

Efforts to Repair the Land

Since the late 1960s, people have worked hard to fix the land. They planted many non-native trees, like Pinus radiata, in areas that were eroding. They also encouraged native scrub, like kānuka and mānuka, to grow back.

By 2002, the Waiapu River area had few natural habitats left. About 26% was pine forest, 37% was pasture (grassland for animals), and only 21% was native forest. Another 12% was kānuka and mānuka scrub. The land was very damaged and had serious erosion problems. About half of the pasture land was likely to erode easily. Many of the rivers in the area were full of sediment and considered very unhealthy.

Sediment in the River

The Waiapu River has one of the highest amounts of sediment in the world. In 2000, it carried about 20,520 tonnes of sediment per square kilometer each year. This is more than two and a half times the amount in the nearby Waipaoa River. It's thought that this sediment might have harmed the coastal and ocean areas nearby.

About one-sixth of all the sediment that flows into New Zealand's rivers each year comes from the Waiapu River. It continues to be one of the most sediment-filled rivers globally. Around 36 million tonnes of sediment are carried by the river each year. This means about 90.47 cubic meters (3,195 cubic feet) of sediment flows into the sea every second. The water in the smaller streams that flow into the Waiapu River is often much cleaner. This is because these streams are closer to the native forests of the Raukumara Range.

Rising Riverbed and Erosion

In the lower parts of the Waiapu River, a lot of the eroded gravel settles on the riverbed. This causes the riverbed to rise quickly. Between 1986 and 2007, the riverbed rose about 1 meter (3.3 feet). Because of this, several bridges over the Waiapu's smaller rivers have had to be raised.

As the riverbed rises, the river itself also rises. This causes a lot of riverbank erosion. The riverbanks eroded at a rate of 8 meters (26 feet) per year between 1988 and 1997. From 2003 to 2008, this rate doubled. In 2005 and 2006, 22 meters (72 feet) of riverbank eroded each year. This erosion is a threat to the town of Ruatoria. Special structures called groynes have been built to try and move the river away from the town.

Māori History and Significance

Ngāti Porou and the River

Paepae pātaka (threshold of a storehouse) in the Waiapu Valley

Māori people lived widely in the Waiapu Valley around the Waiapu River until the 1880s. The river and valley are very important to Ngāti Porou, who are the local tribe. They value the river for its culture, spiritual meaning, economy, and traditions.

Ngāti Porou believe they have had a special connection with the river since the time of Māui, a famous figure in Māori stories. They see the river as something that connects everyone who lives on its banks. The valley, which they call Te Riu o Waiapu, was a safe place to live. It offered protection during wars and provided fresh water and many types of fish. In 1840, Ngāti Porou grew many crops around the river.

The importance of the river is shown in these traditional Māori sayings:

• Ko Hikurangi te maunga, Ko Waiapu te awa, Ko Ngāti Porou te iwi (Hikurangi is the mountain, Waiapu is the river, Ngati Porou are the people)
• Hoake tāua ki Waiapu ki tātara e maru ana. (Let us shelter under the thick matted cloak of Waiapu.)

Early Settlements and Beliefs

The first Māori church was built by the Waiapu River in the 1830s. The village, or Pā, where the church was located was called Whakawhitirā. It was described as the largest in the region. Just before 1840, about 3,000 people lived there.

Many Ngāti Porou hapū (subtribes or clans) still live in the area today. The valley has many marae, which are traditional meeting places. In 2002, about 90% of the people living there were Māori. Traditional culture is still practiced, though it has changed over the last 150 years. The hapū living along the Waiapu River are responsible for protecting the mauri (special nature or life force) of the river. They act as kaitiakitanga (guardians) of the river and its tributaries. The ways they catch kahawai fish at the river's mouth are unique and considered sacred.

Ngāti Porou also believe that taniwha (water spirits or guardians) live in and protect the river. These taniwha are thought to protect the valley and its hapū. Some taniwha believed to be in Waiapu River include Kotuwainuku, Kotuwairangi, Ohinewaiapu, and Ngungurutehorowhatu.

There is a traditional story about two taniwha placed in the river to protect the hapū from other tribes. One was near Paoaruku and another at the Wairoa River. When a bridge was built from Tikitiki to Waiomatatini, some Māori were worried it would disturb the taniwha. The night before the bridge was finished, a storm washed it away, even though the weather had been calm. After that, people believed someone would drown in the river almost every year. A local spiritual leader, a tohunga named George Gage, was asked to help. After his help, the drownings stopped.

The cutting down of forests and land development in the area had a big negative impact on Māori. In 2010, Ngāti Porou reached an agreement with the New Zealand Government to address past wrongs. This agreement included money and the return of land that was important to the tribe.

How the Waiapu River is Used Today

Water Use and Management

Because the Waiapu River has so much sediment, it's not ideal for drinking water. However, local marae and small communities sometimes use the water for daily needs. Farmers also let their livestock drink directly from the smaller streams that flow into the Waiapu River.

Currently, there are no official permits to take, use, or dam water from the Waiapu River or its tributaries. However, a small power station that uses water (a mini-hydro power station) was expected to start working in 2012 on a small stream in the area.

The Gisborne District Council decided that a special water plan wasn't needed for the Waiapu River because very little water was being taken from it. But now, New Zealand is focusing more on freshwater policies. So, a water plan for the river will be created with help from the Gisborne Freshwater Advisory Group. This plan will cover the river's cultural, recreational, environmental, and commercial importance. It is expected to be finished by 2016.

Gravel and Fishing

Gravel is carried by the river and deposited on shingle beaches near its mouth. This gravel is taken from about 12 different places. It is mainly used for building and maintaining roads in the countryside and for forestry.

The Waitahaia River, which flows into the Waiapu River through the Mata River, is famous for its brown trout. Brown trout are a type of European fish that were brought to New Zealand in the late 1860s for fishing.