This is how we're responding in Selwyn.
Knowing that we may be dealing with more severe weather events that are likely to cause flooding, Selwyn District Council is taking steps now to protect properties and infrastructure in our communities.
Through investigating flooding hazards in coastal and low-lying parts of the district, using computer-based flood modelling to predict the extent and depth of flooding, the Council has been able to map areas likely to be at greater risk of severe flooding.
The stormwater network is also currently being improved to increase the capacity of stormwater catchments and flood defences.
There are also a number of projects currently underway to protect more at-risk areas of the district. These include:
Leeston and Hororātā Stormwater Flood Bypass Projects
Leeston and Hororātā are prone to flooding, with surrounding rivers breaching their banks during high rainfall events.
Following flooding events in 2013 and 2018 the Selwyn District Council has been working on projects to divert flood waters around the townships and manage localised flooding within the townships.
In Leeston, a bypass is under construction to redirect the main flow of floodwater away from the town centre for a one in 100-year storm event through a specifically designed channel.
This will restrict water going through the centre of town while still keeping the base water flow through the Leeston Creek, protecting its ecological and biodiversity values.
The bypass is expected to be completed in 2022.
In Hororātā, drainage in the township has been improved and a further drainage channel will be added south of Hororātā this year to divert floodwaters away from the township.
Environment Canterbury has also supported creek and stream clearing projects to remove debris from the Hororātā River, Cordys Stream and Happy Jacks Creek to improve flows and reduce spillover in heavy rain events, while protecting ecological and biodiversity values.
Thanks to a climate resilience grant, Environment Canterbury is replacing the weed barrier on the Halswell/Huritini River. Weed is cut and removed from the riverbed to manage ground and surface water levels in the Halswell/Huritini area.
Cut weed must be prevented from entering Te Waihora /Lake Ellesmere, which is a nationally important wetland of huge cultural importance, or it will severely degrade water quality through release of stored nutrients during decomposition.