Sunday, May 19, 2024

Havelock North stormwater recovery works flow

Work on the Havelock North Streams in the wake of Cyclone Gabrielle is continuing, with
drone surveys and removal of concrete and trees from Mangarau Stream now complete.

Hastings District Council three waters manager, Steve Cave said work on the streams had
been progressing steadily since Cyclone Gabrielle.

The cyclone triggered a significant increase in customer enquiries, which increased from an average of two per month before the cyclone to around 15 per month in the six months following.

“Our team is working its way through a list of jobs, prioritised on the level of risk they pose
during future weather events. Increasing resilience in the Havelock North streams, particularly the Mangarau Stream, is a priority for Council,” said Mr Cave.

Concrete blocks and large tree material, some of which fell into the Mangarau Stream during the cyclone, were removed mid-March.

“The concrete blocks on the stream bed and embankment were shifted out of the main
channel. While they would not restrict normal to above average flows, they needed to be
removed in case of higher flows.”

“Removing the blocks and trees was a complex piece of work that required creating access
for a 55-tonne crane that lowered a five-tonne excavator with a rock breaker into the stream.”

At the same time, the Mangarau, Herehere, Te Kahika, Karituwhenua and School streams, which all take stormwater from the Havelock North dams, were surveyed using a drone.

“The Surveying Company HB was contracted to carry out this work, which involved using an unmanned aerial vehicle (UAV) to capture LiDAR and photographic information. We advised neighbours that the drone would be flying over their property at approximately 80m above ground.”

“That work will inform and further refine options designed to enable Category 2c properties to be moved to Category 1, support cyclone recovery, and improve stormwater infrastructure across all five streams.”

Over the next couple of months, the project team will hold a community drop-in session, complete a draft of an Emergency Action plan and discuss it with the community, continue with maintenance work, and continue work currently underway to meet the Government’s new dam safety legislations due to come into force in May.

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