Emergency Wairau River bank repairs
Emergency works are underway on the Wairau River near Wratts Road in Blenheim after recent rainfall swelled the river, causing erosion to its southern bank.
Rivers Engineer Geoff Dick says the crew worked all weekend and have done a good job.
“We’ve trucked in a lot of rock and created a series of groynes to halt the erosion and stabilise the bank. The emergency repair will protect the bank from future moderate flood events, but this is not a permanent solution. A long term repair will need to be considered next year.”
Geoff says work is also underway to reinstate the Southern Valleys Wairau and Waihopai river intakes following recent rainfall.
“That should also be completed today or tomorrow, so our team get some take time off over Christmas.
“We’ll do a full survey of the Wairau from the Narrows downstream as a priority in the New Year, which will help us prioritise any further work.”
River levels are expected to begin dropping today and the weather forecast is looking positive. The repairs are expected to be completed later today or tomorrow morning.
Marlborough District Council manages the stop bank flood protection system on the Wairau River plain, with a budget of $4m over the ten years 2018 to 2028. In recent years the flow of the Wairau has changed and erosion has been occurring along the south bank of the river, in the 3.5 km reach downstream of the Wairau/Waihopai confluence, and also on the lower 500m of the Waihopai River.
Design of permanent protection works, as planned for in the Wairau River Floodways Management Plan, will provide a high level of protection to the Southern Valleys intake and the adjacent stop bank in a future major flood. The last major flood of the Wairau River occurred in 1983.