Nambung River facts for kids

The Nambung River is a river in the Wheatbelt area of Western Australia. It flows about 170 kilometres (106 mi) north of Perth. This river helps drain the land between the towns of Cervantes and Badgingarra.

Near its end, the Nambung River forms a series of waterholes. These are part of the Nambung Wetlands. The river then goes underground into a limestone karst system. This happens about 5.5 kilometres (3 mi) from the Indian Ocean.

A Look Back in Time

The Nambung River was first seen by explorer George Grey on April 16, 1839. This was during his second trip along the Western Australian coast. He first called it the Smith River. He named it after Frederick Smith, a young man on his team. Frederick Smith was 18 years old and sadly died during the trip. He was also a first cousin to Florence Nightingale, a famous nurse.

The river was renamed the Nambung River in 1874-75. This was done by a government surveyor named John Sherlock Brooking. The longest stream that flows into the Nambung River was later named Frederick Smith Creek.

In 1875, the river was recorded as the Namban by William Edwin Archdeacon. He was in charge of mapping the coast for the Navy. The name Nambung became common from 1888. It comes from an Aboriginal word. This word might mean crooked or winding.

Where Does it Flow?

The Nambung River's area is next to the Hill River to the north. It is also next to Mullering Brook to the east and south. Its main smaller streams are Bibby Creek, Mount Jetty Creek, and Frederick Smith Creek. The Nambung River and Frederick Smith Creek together are about 22 kilometres (14 mi) long.

The river ends on the surface in a limestone area. This is about 9 km south-south-east of Cervantes. It is also 5.5 kilometres (3 mi) from the Indian Ocean coast. The river forms a chain of waterholes. Then, it disappears into a cave system underground. The water eventually seeps out along the coastline.

The Pinnacles are famous rock formations. They are found inside the Nambung National Park. This park is in the southern part of the Nambung River's area. Much of the natural bush land in this area is well protected. It mainly has low scrub plants, less than 2 metres (7 ft) tall.

The River's Secret Underground Life

The Nambung River flows underground into a special rock system called a karst system. This system is next to the Nambung Wetlands, inside Nambung National Park. The wetlands have salt lakes, swamps, and lagoons. Many of these water bodies are separate from the sea. They get their water from rainfall and underground water from the sand dunes and limestone.

Sometimes, the land behind the wetlands floods. When this happens, the water filters down into the underground rock. It then flows into the sea through hidden channels. This means the river's path can be hard to see on the surface. This is because the water goes through the limestone underground.

Salty Water and Rocks

The Nambung River and Wetlands have different levels of saltiness. This can change no matter what is happening on the surface. The underground water is most salty where it comes out into salt lakes. It is also salty in the lower part of the river. Here, salty underground water comes from older rock layers.

This salty water from deep underground makes the water near Cervantes very salty. It can have over 8,000 mg/L of dissolved solids.

Karst Terrain: Caves and Sinkholes

Large amounts of underground water flow to the sea through these rock layers. Much of this water flows through special channels in the Tamala limestone. This limestone was formed a very long time ago, between 1.5 million and 10,000 years ago.

Many features of the Tamala Limestone are linked to the Nambung River. These include underground tunnels and caves. There are also dolines (bowl-shaped hollows) and sinkholes. You can also find limestone pillars and circular dips in the ground. Caves form when slightly acidic water slowly dissolves the calcium carbonate in the limestone. This dissolved material can then be put back into the caves as new rock formations.