Provision of Access to Perform a Geological Survey to the Spillway Rock Abutments of Eildon Dam
Introduction
Vertigo Specialist High Access Services (Vertigo) were engaged by The Eildon Alliance (Goulburn-Murray Water, John Holland Group, GHD & Hazell Bros Group) to assist in performing a Geotechnical Survey of the upstream rock abutments adjacent to the spillways of Eildon Dam, Victoria. Lake Eildon is a significant water source for the Goulburn-Murray Irrigation Project; construction of the embankment dam structure creating this reservoir was completed in 1955.
The Eildon Dam Improvement Project has been instigated at a time of low reservoir water level that allows work to commence on an upgrade to the existing structure with respect to spillway flood volume capacity & embankment / spillway seismic loading capacities.
In May 2004, the Eildon Alliance conducted Geotechnical Surveys with assistance in access issues from Vertigo, via Industrial Rope Access methods.
Scope of Work
A team of Vertigo Technicians installed temporary rope access work positioning systems down the abutment rock faces, above the lake, in conjunction with rescue contingency systems on the spillways. A Geological Engineer was then assisted onto the abutments to log survey data. Vertigo had previously assisted in a similar survey of the nearby Mount Sugarloaf quarry that has subsequently been reopened as a source of material for construction.
The findings from site geological & geotechnical surveys will be used to evaluate the preferred option for effecting the subsequent upgrade of the dam
Outcome
Vertigo provided safe access & egress to the rock abutments for the Engineer to complete the surveys safely and rapidly. The survey data will be used to confirm the preferred option for the dam upgrade that involves- raising the main embankment height, rock anchoring sections of the spillways & modifying the existing spillway gates.