Restoring the Daintree River system

NATURE-BASED SOLUTIONS FOR EROSION

RESTORING THE ICONIC DAINTREE RIVER SYSTEM

Monsoon-battered creekbanks will be repaired in the iconic Daintree River system thanks to a disaster recovery package.

We recently began a project to repair riverbanks damaged by Cyclone Jasper and causing ongoing erosion, affecting the land and sending fine sediment loads down our waterways and, ultimately, to the Great Barrier Reef. Our first timber pile field for this project is almost complete. It’s on Martins Creek, where we’ll be working at a series of erosion sites along about 1.2km of the creek.

Terrain NRM is working with landholders, Douglas Shire Council, Jabalbina Yalanji Aboriginal Corporation and Neilly Group to restore sections of Martins Creek, Cassowary Creek and Saltwater Creek.

A range of nature-based solutions will be used including timber pile fields, bank reprofiling and tree-planting.

Cyclone Jasper recovery work

The $2.7 million Daintree Riverine Recovery project is focusing on damage caused to creekbanks in the floods that followed Cyclone Jasper and is jointly funded by the Australian and Queensland governments under the Disaster Recovery Funding Arrangements (DRFA). Tree-planting will be funded through the Australian Government’s Reef Trust Landscape Repair Program.

Federal Member for Leichhardt Matt Smith said the project is another example of how the Federal and State governments stand shoulder to shoulder, building resilience in the Far North under the Disaster Recovery Funding Arrangements.

“Almost three years on from the devastating impacts of Cyclone Jasper, we are still finding ways to grow back better – protecting our communities and building a Far North better prepared to weather the storm,” Mr Smith said.

Work is scheduled to begin this month (September).

Martins, Saltwater and Cassowary creeks

Terrain NRM Project Manager Max Brownlow said Martins Creek was an important tributary for the Daintree River, which received heavy flows off the mountains.

“We’ll be working at a series of erosion sites along about 1.2 kilometres of the creek,’’ he said.

“At Saltwater Creek, we’ll be restoring and stabilising a creek area that has seen dramatic erosion and land loss since Cyclone Jasper, where floodwater has been coming over the top of the bank and cutting a channel behind it and where the banks are continuing to collapse and recede.

“Cassowary Creek is a smaller creek with very high flows in floods. One side of the creek has receded three metres since the start of this year alone, and almost 30 metres of creek bank has been lost since 2011.”

Two timber pile fields will be built at Martins Creek, along with bank battering, strategic rock placements and tree-planting while at Saltwater and Cassowary and creeks there will be bank battering and widespread tree-planting.

What are timber pile fields?

Timber pile fields are multiple rows of piles, driven vertically up to seven metres into the streambed. They are designed to slow down water and build up sediment, to protect and repair damaged riverbanks. The design allows for vegetation to replace the piles in the long-term.

Max said a hybrid nature-based solution – combining earthworks, trees and in some instances engineered rockwork – was the best option for these sites, with the earth and rockwork acting as reinforcement until the trees established themselves.

“With the level of erosion, there is nothing left to hold soil in place,’’ he said.

Building on other restoration projects

Terrain NRM’s Waterway Health Leader Tamara Wilson said the current project followed similar work led by Terrain NRM – also jointly funded under the DRFA – in the Mossman River system and in different parts of the Daintree river system.

“After severe flooding in 2019, erosion sites were restored at Bamboo Creek and the Mossman River using a combination of nature-based engineering techniques and revegetation,’’ she said.

“We are taking our learnings from these projects – about how nature-based solutions respond in the Wet Tropics and how they complement other engineering solutions – and we are applying them to this new project.”