The need to develop a sustainable management regime for our natural environment is one of the lessons learnt from the horror summer of 2019-20 for Hunter vigneron Wendy Lawson, Catherine Vale Wines, Broke, whose property was burnt then flooded.
Its a story, all too sadly familiar for many landholders, who were first faced with devastating bushfires in late 2019 and early 2020 and when the rains arrived, in many instances they arrived in storms, that wrecked havoc on their burnt out denuded properties.
For Mrs Lawson the first of the two evils arrived on December 27, 2019 as the Gospers Mountain bushfire was raging in Yengo National Park that backs onto her property.
The decision was made by the NSW Rural Fire Service to commence a back-burn operation from a designated fire trail situated on the Catherine Vale Wines property near the adjacent southern boundary to the National Park.
The back burning operation removed all native vegetation ground cover and canopy leaving the property exposed to any future storm damage.
The fire left the steep, rocky catchment and soils that are sandy and low fertility exposed to storm damage.
And the storms arrived February 2020 in fact Mrs Lawson was hosting a local Landcare meeting at the vineyard when the first of the two devastating storms hit.
The damaged landscape didn't stand a chance with a five megalitre dam being completely silted up, infrastructure damage to roads and tourist areas, siltation of the vineyard, gullies eroded and weeds arriving en masse.
"Torrential rain just came through the property leaving a complete mess as there was nothing to stop it because the landscape was totally denuded by the fire," Mrs Lawson said.
Shocked at what had occurred Mrs Lawson sought assistance as to how best to restore the vineyard and surrounding landscape on her property. She contacted Steve Eccles, who operates a consulting business and the pair worked together on preparing an application for financial assistance to undertake the extensive work required through the Rural Assistance Authority Special Disaster Grant Bushfires.
This application proved successful and with $75,000 in financial assistance the work required has just been completed.
Mr Eccles said given the extent of the damage he had to design, locate and implement a series of rock sediment traps in the drainage lines above the damaged areas, to divert and collect runoff water to reduce the sediment flow and its impact on the vital infrastructure.
The rock was wrapped in heavy geofabric and keyed into the landscape, improving the stability of the structures. This assists in capturing sediment as well as run off water, especially necessary as the soil is fine and cause sand and will not assist in sealing the structures. A 30-tonne excavator and other equipment was used to complete the work. Where possible sediment was removed from damaged areas and used in the rehabilitation. To divert overland flow, these areas were shaped and jute mesh organic matting used to prevent erosion. All disturbed areas were sown with known invasive groundcover seeds and legumes suitable for the environment and soil type.
The five mega litre dam was desilted and preventive rock sediment traps installed in the catchment above the dam. The sediment was removed from the damaged contour banks and additional culvert pipes placed in access road.
Temporary sediment fencing was installed below the dam to ensure no sediment movement occurred off the property.
The first flush broadleaf weeds following the fire included, Nagarro Burr, Night Shade and Fireweed. Some of the weed species from this first flush are noxious weeds and or weeds of regional significance. The control of these weeds was undertaken by Adam Bush from Delta Land Management. The control was by hand application of selective herbicide and there was a follow up spray kill application three weeks after the initial application.
Mr Eccles listed some of the take home messages of this work:
1. The prolonged drought, excessive high temperatures and frequency of heat waves resulted in catastrophic conditions
2. The ecology of native landscapes in these conditions, plants drop leaves, twigs and branches to try and save themselves. Some succeed but a number did not, but the exponential tonnage of litter and tinder dry landscape was the reasoning with the conditions of the fire intensity and destruction
3. It should be remembered that the property had undertaken hazard reduction. The catchment above the property would have over 25 % surface rock. In this case there was no lack of hazard reduction and it would be incorrect to say any preventative measures would have made a great deal of difference
Commeting on her previous hazard reduction work on the property adjacent to the National Park boundary over the winter of 2019 and 2018 Mrs Lawson said this was undertaken as a 'cool burn' by Koori Country Firesticks.
"It was a very different outcome to the back burning operations undertaken at the height of the catastrophic fires this summer," she said. "We have to learn to manage the landscape the best way possible so we don't have to burn in a manner like we did this summer.
We have to learn to manage the landscape the best way possible so we don't have to burn in a manner like we did this summer.Wendy Lawson
"The damage to the landscape flora and fauna is unsustainable unless we can manage the environment properly."
In another blow, as a result of the fires, like most Hunter winegrowers her grapes suffered from smoke damage. Only one variety has survived the smoke taint her Arneise grapes.