Bird strike risk low at Te Anau Airport

A proposal to irrigate wastewater and produce silage near the Te Anau Airport, Manapouri, can only go ahead if a comprehensive management plan is put in place to reduce the risk of bird strike.

The Southland District Council commissioned Avisure to assess bird strike risk at the airport. The report is expected to be received by councillors at the Te Anau Community Board on Wednesday.

Surveys at the proposed irrigation site, at the northern end of the airport, indicate a high attraction of large flocking birds that could be a serious hazard to aircraft.

Spur-winged plover are the most common followed by paradise shelduck, black-backed gulls, Canada goose and grey duck. The plovers were assessed as the highest strike risk during the survey of the land near the airport.

The site is already highly attractive to birds because of the current method of allowing grass regrowth and then grazing along with shelter belts and water ponding around the bog area.

Two main wastewater options that have been debated include a pivot or subsurface irrigation. A decision has yet to be made on the irrigation method.

However, Avisure’s report says the pivot system would be slightly more attractive to birds.

Avisure recommends that a comprehensive plan is developed to manage risk and is backed by regular monitoring and evaluation.

Mitigation could include adopting a long grass policy, eliminate standing water, infill existing depressions and dispersing roosting birds.

If this is done, along with regularly review, then either a centre pivot or sub-surface system could feasibly be adopted.

The report says the airport has the potential to develop in the next 20 to 30 years to include more airport movements with aircraft types that are larger, faster and more susceptible to bird strike. There were 384 aircraft movements recorded in 2017, and small aircrafts (including helicopters) are the main users of the aerodrome.

Only one bird strike has been reported at the airport in the past five years.

Yet, New Zealand Civil Aviation Authority indicate two strikes in 2015 and one in 2016.

‘‘It is generally acknowledged that general aviation pilots are far less likely to report strikes than commercial airline pilots, so there is probably an underreporting of strikes at TEU,’’ the report says.