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Rangitāiki waterway structure project begins

Friday, 23 January 2015 10:00 a.m.

A project is under way to locate all culverts in the Rangitāiki catchment area, and Bay of Plenty Regional Council is asking for help from the public.

Anyone who knows the location of culverts - or other waterway structures such as fords, weirs and floodgates - is asked to contact the Council. An engineering team is out in the field from today to seek out the structures.

Culverts are common in Bay of Plenty streams and rivers, and they can present problems for fish and the movement of small fauna in waterways. New Zealand has about 40 native freshwater and several sports fish species, and about 70 percent of these are threatened or at risk. Many iconic species such as whitebait and eels need to move between the sea and rivers to complete their life cycles. They also migrate upstream and downstream between different fresh water habitats.

If culverts and other structures are not installed correctly they can delay or block fish movement. Fish and invertebrates may be unable to reach habitats critical to their life cycle completion. Numbers can dwindle, and entire species could be lost. The Bay of Plenty Regional Council therefore aims to identify all problem culverts so they can be fixed where possible, in collaboration with other stakeholders, to benefit fish life.

“There are potentially thousands of culverts out there and we would appreciate the public’s help in finding the ones that are not fish-friendly,” says Bay of Plenty Regional Council Engineering Manager David Boothway, who is a member of New Zealand’s Fish Passage Advisory Group.

The field team will focus on public roads and waterways, and the estuarine environment. It will start at the sea and work inland, looking at any structures around waterways to identify problems. Council will then identify where corrective action is most needed.

“If there’s a barrier there are ways of retrofitting them,” Council graduate engineer Marnie Fornusek says. Solutions include installing ramps and ropes where a culvert is perched, which means it’s above the water and fish can’t reach it to pass through.

Under the Freshwater Fisheries Regulations 1983 and Resource Management Act 1991, the Department of Conservation and regional councils have specific responsibilities to manage fish passage in waterways. For structures built after January 1, 1984, culverts and fords may not be built to impede fish passage without a permit from DOC, and any dam or diversion may require a fish facility.

Bay of Plenty Regional Council has already demonstrated its commitment to sustainable engineering, with a current project installing two culverts, a weed cordon and a weir between Thornton Lagoon and the Rangitāiki River set to allow for added water exchange between the two waterways, improving the water quality and helping fish life flourish.

If you know of any structures around our waterways that fish may struggle to swim over or around, please call Bay of Plenty Regional Council on 0800 884 880.  We would love to work collaboratively with all parties to help remedy the situation.

An example of how a culvert should look:

Rangitaiki waterway

An example of a perched culvert that creates a barrier for fish:


Rangitaiki waterway