A hedgehog is one of the many things found to have blocked Rotorua's wastewater system in recent years. Photo / Getty Images
A hedgehog is one of the many things found to have blocked Rotorua's wastewater system in recent years. Photo / Getty Images
A hedgehog, pig's head, and a child's Tonka truck are just some of the items responsible for causing wastewater blockages resulting in more than 100 spills in Rotorua in the past three years.
Data obtained by the Rotorua Daily Post through a Local Government Official Information and Meetings Act revealsthat while there has been a total of 109 wastewater spills since 2019, there has been a drop in this time.
In 2019/20 Rotorua Lakes Council recorded 56 spills and in 2020/21 there were 37. This financial year to date, there were 16. This did not include two wastewater overflows into Rotorua streams last weekend, caused by a mix of fat and wet wipes. The council warned people to keep clear of three streams on the weekend after the two separate incidents by Petrie St and Martin St.
The council would not say how much the spills had cost ratepayers to clean up and fix.
Deputy chief executive of district leadership and democracy Oonagh Hopkins said costs for overflow responses were not itemised.
Responses to overflows were included in the lump sum contract payment provided to Trility for the ongoing management of the network. Contracts for the years prior to council engaging Trility were managed the same way, she said.
In 2020, the council entered into a 10-year $156 million deal with private consortium Trility to manage the city's wastewater.
A sign was erected in the culvert off Tarewa Rd last year after a foreign object was the suspected cause of a wastewater overflow in Rotorua. Photo / Andrew Warner
In Tauranga, the rough cost of responding to wastewater spills in the past three years is estimated to be about $3m and the Western Bay of Plenty District Council has spent about $65,000 in the past three years.
Many of the spills were recorded in residential streets, with repeat blockages and spills in Alison St and Goldie St in particular.
However, details on how the environment was impacted from such spills and for how long were "not recorded in a way that can be collated". For some events, they might not be recorded at all, Hopkins said.
Finding out such details would require "extensive investigation" which the council could charge for, she said.
Under the Local Government Official Information and Meetings Act, councils have 20 working days to respond to a request. They also have the ability to extend this response time if needed.
There was no extension to this request.
"Council and its contractors respond in accordance with the Regional Best Practice Guide for the Management of Wastewater Overflows which was developed by council, together with Bay of Plenty Regional Council and other district councils in the region," Hopkins said.
"Council also follows advice from Toi Te Ora Public Health and Bay Of Plenty Regional Council about the appropriate response i.e. swim/recreation ban, signage etc."
Rotorua has 80 pump stations and more than 500km of sewer mains and 8000 manholes.
"There is always a risk that there could be a network/pipeline fault or damage that causes wastewater flow obstructions," Hopkins said.
Other objects that have caused blockages in recent years include cutlery, a 5-litre oil can, building materials, cleaning wipes and fatbergs.
Hopkins said the council had, in recent years, increased work to minimise the risk of overflows. This included changing pipe water blasting from annually to quarterly in some areas; CCTV inspections of each gravity main; increase in personnel via Trility to manage the assets and carry out network inspections; and with "improvements in the way of data recording and network monitoring".
