Craig Scott of MWH, now part of Stantec, gives an engineer’s personal reflections on managing an emergency dam decommissioning at Haldon Range Dam reservoir in Marlborough, New Zealand.
The Haldon Range dam is a 25m high earthfill farm dam constructed for irrigation water to supply a new vineyard development. It is located upstream of the town of Seddon which has a population of 507, with a large local employer being a lime and salt works.
The Haldon Range dam is similar to the many tens of thousands of irrigation and water supply dams that exist globally to manage water supply for individual landowners, small communities or groupings of farmers. Similar to Oroville, the anticipation or actual structural failure of any dam or its appurtenant structures causes significant stress for the local population. It captures the attention of the media. It can be the subject of numerous court cases, and for a long period the structure can exist as a risk to the downstream population until actions are completed to reduce that risk.
This article is a synopsis of Craig’s personal experience as an engineer, engaged by the Marlborough District to inspect the damaged Haldon Range Dam immediately following earthquake induced damage; recommend actions to reduce the risk; then manage the implementation of the physical work to reduce the risk in as short a time as possible.
Read International Water Power & Dam Construction – ‘Small Dam–big task’ published July 2017 here.