Slope strategy for Patonga Dr

A strategy for slope stability risk reduction treatment on the southern side of Patonga Dr near Pearl Beach has been recommended for adoption.

The Slope Stability Risk Assessment prepared by Douglas Partners covered issues with the stability of the cutting and slopes above Patonga Dr, between the hairpin bend and the water reservoir.

The report listed several recommendations in a general order of priority for both the cutting adjacent to the road pavement and the slope above:

It suggested that council scale and remove loose fragments and joint wedges from along the sandstone cut face.

It also suggested the line marking of a traffic exclusion zone 0.5m from the toe of the cut face, stabilisation measures on completion of scaling works to support unstable wedges or rock bolts and rockfall netting or shotcrete to the weathered zones of the cut face and crestal zone.

It also suggested the application of support measures or removal of potentially unstable boulders upslope from the crest of the rock face and the installation of a rockfall catch fence along the crest of the cut face.

In relation to the slope above the cut face, the report recommended that an engineering geologist carry out a detailed inspection and assessment of potentially unstable boulders and joint blocks between the crest of the cut face and the ridge.

It also recommended the selected treatments to boulders and joint blocks nominated in inspection which could include their removal, installation of support measures or underpinning.

The report further recommended the installation of an engineer-designed rockfall catch fence along the crest of the cut face.

The first recommendations for both the cut face and the above slope have already been constructed, according to a Gosford Council report.

The report stated that $60,000 has been spent on the work to date.

It stated that the consultant was currently working on a list of individual rock hazards that required support measures that could be used to brief contractors.

Douglas Partners were also conducting an assessment for the section of Mt Ettalong Rd below Patonga Dr between the hairpin bend and the beach carpark.

Council agenda CIT.26, 4 Sep 2007