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Westport’s stormwater network receives a resilience boost

08 May 2024

Westport’s underground stormwater network is now more resilient and better able to protect against floodwater infiltration (backflow) at many key stormwater outfalls. 

Several initiatives have recently been completed to achieve this, with funding secured by Buller District Council from Central Government. 

Traditionally, installation of flap gate valves was the main method used to protect against backflow at pipe outfalls.  

These relied heavily on regular maintenance to ensure the hinges were free (they were prone to seizing), the mating surfaces were clean to ensure a good seal, and that debris was not restricting the opening or closing of the device. 

Luckily, there are a number of modern alternatives to flap gate valves available that offer superior backflow performance, combined with a much lower failure rate.  

Of these alternatives, WaStop® brand backflow devices are amongst the best and Buller District Council has installed these recently at a number of key stormwater outfalls across Westport. 

WaStop® valves operate through an ingenious mechanism and this can be observed in action via the link below. 

Crown Infrastructure partners’ Better Off funding has fully covered the cost of supplying and installing 14 of these WaStop® devices at key stormwater outfalls throughout the Westport township.   

Outfalls benefitting from this funding and project are: 

  • Hughes Place/Disraeli Street outfall 
  • Bentham Street outfall 
  • Brougham Street ‘Brick Arch’ outfall (Buller River) 
  • Brougham Street east outfalls (x 2) into the Orowaiti River 
  • Eastons Road bend 
  • Snodgrass culverts into the Orowaiti River (x 2) 
  • Russell Street north outfall 
  • Peel Street north outfall 
  • Romilly Street north outfall 
  • Wakefield/Domett Street outfalls (x 3) 

Additionally, five WaStop® valves were installed between February and September 2023 in stormwater drains around Westport. This work was funded by the National Emergency Management Agency’s (NEMA) flood recovery programme. 

WaStops have been installed at two locations on Cats Creek at 76 Domett Street, and in Henley Street, Roebuck Street and Kawatiri Place. This brings the total installed in the network to 19. 

These, in combination with other improvements, will speed up the outflow of stormwater after a flooding or heavy rain event.  

Since they have been put in place, the WaStop® valves have prevented backflow from the Buller River into the stormwater network and reduced the associated backflow into some of our wastewater pump stations.  

The use of these valves, in combination with other works has seen better recovery times after heavy rain at several locations throughout Westport. 

If you’d like to see a WaStop® valve in action, here’s a YouTube clip showing how they work:  

For further information please contact: 
Manager Infrastructure Delivery 
Eric de Boer