History of the Waikanae River

 

 

During the past 100 years the landscape surrounding the Waikanae River has changed with the clearing of forest on the coastal floodplain and in the upper catchment. Early settlement of the area was generally in areas only marginally affected by floods, thereby the hazard  was fairly nonexistent. For example, when the river shifted course Maori tended to move from settlements affected by flooding. Early European settlers used local knowledge to select sites that didn't flood.

More recently, development on the Waikanae floodplain has not been so appropriately located. Most flood-free sites are already built on, and new development has had to use the more marginal sites. Because modern settlements are not easily moved, they are dependent on structural methods such as stopbanks for protection.  Natural floods combined with how people use the floodplain, has created a flood hazard.

After the February 1955 flood, which caused extensive property damage, an erosion and flood control scheme was built. But despite the stopbanks and erosion protection works, medium-sized floods have continued to cause damage. A major flood in the Waikanae River today could cause millions of dollars worth of damage to property and community assets. The social and psychological costs would add considerably to the devastating effect of such an event.