The area will be the latest part of Northland to be issued with new maps showing the impacts of a 'one in a 100 year' flood. The maps - developed over several years - form part of the programme, which focused on reducing flood risks in 26 Northland catchments at highest threat, including 17 in the Far North.
The NRC's Te Hiku constituency representative, Monty Knight, said council staff will be writing to the owners of about 2600 affected properties shortly detailing the updated flood risk to their properties and directing them to the new maps. The council has already released flood maps for 24 catchments over the past three years to raise awareness of where flood hazard areas are and help inform public and district council decision-making.
"It will probably come as no surprise to locals to hear the Awanui catchment has been one of the most challenging for us to map for a number of reasons.
Flow through the Kaitaia itself is also heavily influenced by the Whangatane Spillway on the north side of town, which typically diverts roughly two-thirds of flood flow from the Awanui River."
The new models cost about $250,000 and forecast not only the predicted impacts of a '100 year flood', but also incorporate government climate change projections on storm rainfall intensity and sea level rise. There's a 1 per cent probability of such a flood occurring in any given year.
Many people living in the Kaitaia area are already familiar with heavy rainfall events and how these can affect their properties. "
The new Awanui flood maps incorporate a variety of new information and modelling, including the latest available storm data from the National Institute of Water and Atmospheric Research. They show that should a 100 year event hit Kaitaia, the worst affected areas would be within known flood-prone areas. The largest flood in recent times was in July 2007 and saw the Tarawhataroa Stream stop bank overflow, flooding low-lying areas. The new maps will replace previous hazard maps and would also complement a range of other extensive work the regional council has planned to reduce flood risk in the catchment. This includes a $600,000 project to modify the Whangatane spillway intake due to start next year.
General information about flood mapping is available from www.nrc.govt.nz/floodmaps.