New Zealand Nelson BushFires Case Study

Background

On February 5th, 2019, two fires began between the Nelson and Tasman district. These fires would soon be known as ‘The Nelson Bushfires’ and one of New Zealand’s most devastating bushfires since the Canterbury forest fire of 1955. Due to the intensity of these fires, the New Zealand government not only declared a state of emergency the following day, but more than 22 helicopters were also put into action to fight the blaze – which is the biggest aerial firefight recorded. This emergency declaration would evacuate more than 3,000 residents from the Wakefield and Pigeon Valley areas which were located on the northern tip of the South Island of New Zealand. By the time the bushfires were declared ‘controlled’ on March 6th, the bushfire had already raged across more than 2,300 hectares (5,700 acres) with a 25km radius. These bushfires not only had immediate impacts on the environment and surrounding residents, but it also resulted in prospective long term adverse effects that include the human health (physical and mental) and the global carbon cycle (increase production of carbon due to loss of environment). 

Once the bushfires were controlled, the standard procedure was to minimize the disturbance of the soil around the affected areas. As this bushfire was so intense, any remaining root mass in the soil had already been destroyed. This meant that any significant rainfall would result in the soil becoming hydrophobic, causing large-scale erosion permanently. Rib Coulson and his team at RST Environmental Solutions (NZ) were tasked to come up with an erosion control system that would stop sediment getting into the waterways and the sea, which was only a short distance away.

For this erosion and sediment control project, RST Environmental Solutions (NZ) teamed up with Global Road Technology (GRT) to play a leading role in helping New Zealand recovery from one of the worst bushfires in the country’s history. Since this project was situated in a region where trucks would have difficulty moving, meticulous planning was needed to not only to guarantee compliance with regulations and standards, but to also ensure that potential health, safety, and environmental risks were realized, managed, and mitigated. 

Challenges

As this recovery project was located internationally in New Zealand and would cover 95 hectares of the affected areas, GRT Engineers were required to travel to the project site to assist RST Environmental Solutions in completing several area assessments before product application was to begin. Furthermore, due to mountain slope angles being greater than 30-degrees, there were several challenges in properly applying the product evenly on the affected areas. This project would require five days to apply 600 IBC loads. 

In addition, as it was determined that the natural soil of the affected areas would have no root mass after the bushfire, it was determined by the team that the affected areas should first be sown with grass seeds to raise the root mass in the soil and top cover. By raising the root mass in these areas, it is expected to reduce the damage that would potentially incur from future rainfall.

Solutions

Due to the immense size of the project and the unnatural terrain that the product would require to cover, RST Environmental Solutions selected GRT: Enviro-Binder as the best option in erosion and sediment control. This selection would result in the largest aerial application of an erosion control product in the history of New Zealand, if not the world. Our New Zealand distribution partner DuraVeg, a part of PGG Wrightson Turf, supplied the GRT: Enviro Binder to the project. DuraVeg offers New Zealand sustainable erosion and revegetation products and services and is at the forefront of innovation, delivering complete environment rehabilitation and erosion control solutions to meet the demanding characteristics across the New Zealand landscape. 

GRT General Manager Daniel Grundy said:  “GRT was proud to be part of this critical, environmental protection and rehabilitation project. The Nelson bushfire was a devastating event that left hundreds of hectares exposed to erosion – GRT: Enviro-Binder was a key part of the initial stabilisation of these areas.”

On June 13th, two fixed-wing aircraft travelled through the affected areas to sow the affected project areas with grass seeds. Once the initial task was completed, the product’s application would follow. Tararua Heliworks was the selected organisation that ensured that the application of the product went evenly over very rough and steep terrain. The pilot’s exceptional skills were very critical to the quality and success of the 95-hectare application.

GRT: Enviro-Binder, a non-toxic and environmentally friendly product, was the selected product for the erosion and sediment control as it:

• Was a uniquely developed product that followed the ideal of “STOP EROSION AT THE SOURCE”
• Provided exceptional erosion control immediately after application.
• Met the strict environmental criteria imposed by the New Zealand Government and partner company, RST Environmental Solutions (NZ).
• Required minimal maintenance, unlike conventional methods. 

GRT Enviro-binder is a drying polymer emulsion sprayed on or worked into the surface of rail embankment to provide a waterproof, durable, surface that prevents erosion. 

Benefits:

The GRT Enviro-binder also provided many innovative benefits and delivered high performing results that were expected from the product:

• Only required 5% of polymer in 5,000 Litres of water using modified buckets to ensure even application.
• Continued to provide exceptional results even through an unconventional aerial application.
• Minimal soil preparation for a production application
• Waterproof product; not affected by high rainfall or storm seasons. 
• Cost-effective results

Read more about how GRT played a critical role in helping New Zealand bushland recover from a devasting bush fire here.