Hillwood Stream, located in Wakapuaka north of Nelson City, has been identified as a key source of flooding to private property and State Highway 6 during heavy rainfall events.

The existing stream channel alongside the highway is undersized and prone to gravel build-up, which further reduces its capacity. As a result, floodwaters can overtop the channel and flow across the highway.

The Hillwood Stream Upgrade project is part funded by the Regional Infrastructure Fund to improve flood resilience for the Wakapuaka community by increasing the stream’s capacity through channel enlargement and realignment, along with the construction of earth bunds to help contain floodwaters. A purpose-built gravel trap will also be installed to enable the safe and ongoing removal of excess sediment, while minimising impacts on the surrounding environment.

The Hillwood Stream project is adopting a “room for the river” approach, providing more space for floodwaters to spread safely into the natural floodplain during heavy rainfall, reducing flood risk while improving the health of the stream and surrounding environment.