Lake Ōmāpere’s swans have caused a headache for power company Top Energy, hitting power lines up to 10 times a month - but a head-spinning solution has been found.
Lake Ōmāpere’s swans have caused a headache for power company Top Energy, hitting power lines up to 10 times a month - but a head-spinning solution has been found.
After repeated disruptions on its power line near Lake Ōmāpere in the Far North - up to 10 a month - lines company Top Energy found an unusual cause of the inconvenient outages, and an innovative way to prevent them.
Swans, and other heavy-bodied waterfowl from Lake Ōmāpere, were continually flying into the power lines, causing intermittent disruptions.
In response, the company has now installed a series of bird deterrent devices on the lines, which spin and scare off the birds.
Top Energy spokesperson Philippa White said the power line, which supplies about 736 customers, had 23 bird strikes in the early months of 2024, and up to 10 a month causing intermittent power disruption events of two to three seconds.
“Prior to installation of the bird devices, we experienced an average of around 10 bird strikes a month along this powerline. This is now significantly reduced,” White said.
Top Energy has come up with an innovative solution to swans flying into its power lines from Lake Ōmāpere - spinning bird deterrent devices on the cables
The line has 32 bird deterrent devices units on it and across the whole Top Energy network the company has installed more than 60.
Top Energy’s network is equipped with protection equipment that can detect events such as wire clashes.
“Due to several outages affecting this line, we patrolled it to investigate possible causes and found dead swans. Analysis of the powerline’s protection equipment data confirmed bird strikes as a consistent cause,” she said.
White said the bird deterrent devices are purpose made and designed to reduce bird contacts with powerlines and minimising bird deaths and injuries in areas with a high density of large birds capable of disrupting power supplies.
“Bird deterrent devices, such as the ones deployed on the powerline are an industry accepted method of reducing mid-span bird contacts with power wires.”
Lake Ōmāpere is home to a large population of wild swans and other heavy-bodied waterfowl. These birds, especially when flying low while landing or taking off, can collide with the powerlines.
The devices are brightly coloured and designed to rotate in the wind, making the powerlines more visible to birds, particularly in low-light conditions.
The lake was formed when an ancient lava flow blocked a valley, forming the northern shoreline. It is 5km in length and covers 12.3sq km, however it is only 2.6m deep (and as low as 1.5m during summer). The lake has few inflow streams, mostly in the southern part of the lake. The Utakura River (south-western margin) is the main outflow which goes to the Hokianga Harbour.
In May 1845 the Battle of Puketutu, an engagement of the Flagstaff War, occurred at the pā of Hōne Heke at Puketutu, on the shores of Lake Ōmāpere. The lake level was lowered between 1903 and 1929, but by 1947 silting had restored much of its level.
The water quality in the lake is generally poor and the lake is prone to blooms of toxic algae. It is managed by the Ngā Kaitiaki O Te Roto Ōmāpere Trust.
