Waitomo District Council will soon kickstart a project to increase the resilience in its urban wastewater networks, and it will require the help and support of property owners and tenants.

Council’s water services staff will soon be going door-to-door throughout Te Kūiti, Piopio and Maniaiti/Benneydale undertaking visual checks on private stormwater and wastewater outlets.

This includes inspecting gully traps and downpipes to identify potential risks to the network.

Gully traps (pictured) are connected to a house and must be installed no less than 25mm above a paved surface such as a concrete driveway or foot path and no less than 100mm above an unpaved surface such as gardens and grass areas.

Non-compliant gully traps can impact a property and the network during a storm and can lead to severe flooding.

Downpipes from the roof should be connected to a private soakhole or a stormwater network with Council approval. Downpipes should not be connected to the wastewater network.

General Manager Infrastructure Services, Shyamal Ram says cyclones and heavy rain events are becoming more frequent, and Council has recognised the need to build more resilience in both the stormwater and wastewater network.

“The wastewater network is only designed for wastewater discharges. Stormwater ending up in the wastewater system overloads the network leading to wastewater overflows,” says Shyamal.

“During heavy rain events, wastewater can overflow and get into our waterways which has a detrimental effect on our environment.

“It also overwhelms our wastewater system and can increase up to 10 times more than the average daily flow, which then causes overflows. One non-compliant roof downpipe connected to the wastewater equates to 40 dwellings.

“This increases the cost associated with wastewater pumping and treatment and can lead to the contamination of private properties and the environment.
“By working to identify potential risks to the network, this should make a difference to the resilience of the wastewater network during storms.
“Our water services staff have also been working to clear open drains and stormwater outlets throughout the district.”

Starting this month, weather permitting, inspections will be undertaken in six stages, with the first section starting at the north end of Te Kūiti. Council staff will be clearly identified and prior notice will be given.

A calling card will also be left after the inspection with details of Council’s inspection.

“We would appreciate it if residents were helpful when our staff call around, as it would make our job much easier,” says Shyamal.

Click here for more technical information about gully traps and downpipes, and to see the inspection programme list.