Department of Conservation (DOC) will carry out continual maintenance on parts of Newcastle Track near Luggate after recent storm water caused further erosion and growth of a major slip in the track.
DOC senior ranger Annette Grieve told the Wanaka Sun, “DOC is working with the adjacent landowner on proposed intervention measures to control scouring of the terrace edge above the track. Despite the proposed instigation of remedial measures, we expect some gully erosion through exposure to the elements as the gully walls seek to establish stable side walls. Because of this, ongoing maintenance of the track and visitor caution during heavy rain events will be required.”
The riverbank area is controlled by the DOC and remains open. Local residents noticed the recent washout after heavy rains two weeks ago and reported the formation of a new slip.
A geotechnical report last August for Otago Regional Council (ORC) includes a July 2018 commissioned study by ORC and describes large scale gully erosion on Reko’s Bluff, a terrace face on the north bank of the Clutha/Mata-Au River. This area has been gradually changing since 2015, but recent major rainfall has caused the issue to worsen, including steep gravel cliffs eroding and alluvial fans forming in the river, thereby damaging parts of the Newcastle Track. The former tussock grassland, which once acted as a sponge to retain rainfall, was converted to pasture grasses in 2014. The current landowners installed irrigators this year, which reportedly have the potential to exacerbate erosion. The long-term impacts of the Reko’s Bluff washouts on the Clutha River ecosystem are said to be unknown.