What is proposed?
He aha e marohitia ana? I What is proposed?
Rotorua Lakes Council committed to progressing a Tarawera wastewater reticulation scheme as part of its 2021-31 Long-term Plan with an expected cost at that time of $22.5 million. This followed the work of a steering group that was established following strong interest by the community to have a reticulated sewerage scheme for Tarawera.
The steering group, which included iwi and community representatives, considered a variety of options to come up with a preferred option that would best serve the community and could be implemented in an affordable way. The preferred option that was subsequently adopted and is now being progressed will see Low Pressure Grinder Pumps (LPGP) installed on each property and connected to a mains pipeline that will connect the Tarawera network to the existing Ōkāreka wastewater pump station. From there, wastewater will be pumped to the city’s main wastewater treatment plant.
Stage 1: Construction of the sewerage mains network commenced in May 2023 and is advancing well, which comprises of all equipment that is installed into the street to collect sewage from each property and transport it to the city’s main Wastewater Treatment Plant (WWTP) (Approximately 24km of pressure pipelines, three pump stations, electrical systems, fiber connections, boundary assemblies and testing).
Stage 2: Connection of all properties to the sewerage mains network. This includes decommissioning of existing sewerage systems, installation of Low-Pressure Grinder Pumps and connection from each property to the sewerage mains network. (446 LPGPs, 44kms of pipelines, electrical, alarms and grounds reinstatement). Please view our project Frequently Asked Questions here.
Why is it important?
Lake Tarawera is a taonga tuku iho (ancestral taonga) for Tūhourangi and Ngāti Rangitihi, and a taonga of immense importance to Tarawera communities, Rotorua residents and Aotearoa New Zealand.
Declining water quality means action is needed now to protect the lake. A significant amount of nitrogen and phosphorus in Lake Tarawera comes from natural sources like geothermal so action is focused on the “manageable load”. Mana whenua, Government, Rotorua Lakes Council (RLC) and Bay of Plenty Regional Council (BOPRC) are investing in protecting water quality of the Tarawera catchments through the Tarawera Lakes Restoration Plan. This includes actions to manage the effects of land use on the lake.
Tarawera property owners have been asked to contribute to the collective effort by supporting sewerage reticulation. Reticulation will also reduce public health risks associated with poorly performing on-site treatment systems and will contribute to maintaining the bathing water quality of the lake.
Dealing with wastewater at Tarawera via reticulation will have an immediate impact on manageable nutrient loads and water quality.
Most homes at Tarawera currently rely on some form of septic tanks to manage their wastewater but these leach over time and are no longer acceptable or allowed under BOPRC rules (Plan Change 14 – OSET rules) aimed at improving the health of the lake. Iwi and the community want to achieve improvement through implementing a suitable sewerage scheme to help enhance the mauri (life essence) of the lake for future generations.
Reticulation will reduce public health risks associated with poorly performing on-site treatment systems. Removing potential sources of e-coli (such as septic tanks) is also important to maintain the bathing water quality of the lake. If reticulation were not happening BOPRC OSET rules would apply, and this would require an advanced on-site wastewater system with nutrient reduction on each property.
This is not physically possible for about 170 properties at Tarawera because of property size, slope and other practical on-site conditions. The cost of a compliant OSET system is approximately $28,000 to install and ongoing consenting, operational, maintenance, repair and renewal costs would be the property owner’s responsibility.
