South Katoomba land slip after rains creates deep channel

There were also smaller landslips in a number of area, including one at South Katoomba, which property owner James Perkins is still waiting for council to repair.

Mr Perkins said he believed the slip was "inevitable" because there had been no proper drainage in place.

The land fall left a channel several metres deep across the front of his property and also washed enormous quantities of silt into Kedumba River which flows through to Katoomba Falls.

"For years the council has been discharging all of the stormwater collected from Warialda Street and Abbotsford Road through a pipe into the unformed section of Warialda Street," he said.

"There is no infrastructure or energy dissipation devices to control the flows and, as a result, stormwater exits the pipe at high velocity."

When more than 400 millimetres of rain was dumped on the Mountains over the four days in February 2020, the hillside around the discharge pipe gave way, Mr Perkins said.

"The end result was about 100 tons of silt and rubbish washing directly into the headwaters of the Katoomba Falls creek. It also created an erosion channel about four metres deep and about eight metres long straddling the front boundary of the property I own."

Mr Perkins said he had been in regular discussions with council but "after 18 months the stormwater pipe and the hole is still there".

A council spokeswoman said last year's rain, as well as another heavy fall of 307mm in March this year, had caused a large amount of damage across the Mountains.

In the case of the Warialda Street landslip, a design had been developed to repair the flood damage which will give complete protection from future storms, she said.

"Council has prioritised this project for funding with many other areas damaged by the major flooding event earlier this year."

She said COVID-19 had delayed many of the repair projects but "remediation will be completed as soon as possible".