Geotechnical

Coronet Peak Snowmaking Reservoirs

Our work on the Coronet Peak Ski Area Snow Making Infrastructure and Reservoirs was recognised in 2010 when Hadley Consultants won the Supreme Award at the New Zealand Engineering Excellence Awards.

View an article on this project in the May/June 2011 IPENZ Engineering Insight magazine.

Hadleys were involved in the design and project management of three snowmaking reservoirs at Coronet Peak Ski Area – Rocky Gully, Elephant Pit and Sarah Sue – in order to expand their snowmaking facilities.

Coronet Peak is located at an elevation of approximately 1,600m. It is an alpine environment located on an aged landslide and is approximately 15km from the Alpine Fault. The most efficient form of water storage was determined to be achieved by developing existing natural depressions. Preliminary analysis was performed across the site (comprising approximately 280ha) to identify potential reservoir sites using test pitting, core drilling and material testing. 

Due to the risk associated with water impoundment structures, all three reservoirs were the subject of detailed site investigation work comprising geological mapping, material testing (including Ring Shear and Triaxial testing) and borehole testing comprising core recovery and SPT testing.

The Sarah Sue Reservoir is the largest of the three and involved over 50,000m³ of earthworks. Due to the complications of the site, including the active landslide and weak fluvial materials underlying the site, construction was staged between two summers. This allowed us to preload the potentially weak subsurface material over an extended period of time while performing detailed survey monitoring. After satisfactory settlement results the second stage of construction was performed. This project had many challenging aspects with high altitude conditions, short construction seasons, complicated geology and was commissioned on time for the snowmaking season and under budget.