In the mid 1990's, Gosford City Council engaged Shirley Consulting Engineers to review the earlier maps produced internally by Council in the mid-1980's and to then undertake a formal identification of the various areas within the city area 'subject to landslip hazard'; this area encompassed six 1:25,000 scale CMA maps and extended from Wiseman’s Ferry to Kulnura, and from Patonga to Forresters Beach. The area also included Mangrove Mountain, Somersby, Umina, Koolewong, Gosford & Lisarow. The Council also requested that the study result in specific recommendations / guidelines as to methods of dealing with the identified hazards and a framework for the proposed development control plan [DCP] for areas affected by landslip hazard.
This major hazard mapping & planning study resulted in:
1. Detailed maps of the Gosford City Area at a scale of 1:25,000 which identified areas of potential landslip and rockfall (available for viewing at the Council information desk); and.
2. Policy recommendations which culminated in a new DCP [viz: DCP 163] for the Gosford City area.
The recommendations provided to Council embraced the Australian Geomechanics Society March 2000 Guidelines for Landslide Risk Assessment and provided a rational basis for the assessment of the content of geotechnical reports submitted to Council.