The heavy work is completed on the floodwater detention dam between Raumanga and Maunu but apart from a small stream running through the valley floor there is hardly a drop of water in it.

The 18-m high dam will hold up to 1.27 million cubic metres of floodwater only during and after heavy rain (about two-thirds of the capacity of the existing Whau Valley dam which supplied Whangarei's drinking water). It will work by slowly releasing the trapped stormwater over a couple of days, reducing river swelling and downstream flooding. Dubbed the Kotuku Dam, after the name of the Maunu street that accessed the site, it will reduce flooding in Whangarei's Central Business District and the Raumanga Stream floodplain.

Construction started in August 2014 on one of the biggest engineering projects Northland Regional Council has undertaken. It is expected the $10 million dam will be officially opened and operational in April.

It is being paid for via the targeted Whangarei Urban Rivers Management Rate on more than 17,000 properties in the CBD and contributing catchment.


The NRC had to buy 20 properties across the roughly 30ha required.