Kerikeri at the Crossroads: Infrastructure Issues

4 minutes ago

4 min read

For a long time, Vision Kerikeri has pressed for recognition of a simple principle: Infrastructure must not lag behind growth. That’s important for effective town planning. And it's more important than ever, because the Proposed District Plan (PDP) aims to allow a very large amount of infill and dense building across central Kerikeri.

During PDP hearings last year, Council officers stressed that Kerikeri is “infrastructure-ready” for future dense growth. But research shows our infrastructure is far from ready.

Under-designed sewage system

Kerikeri’s wastewater plant illustrates the problem. Before the current plant was built, engineers recommended 3 treatment units (able to treat 1,500 m³ of sewage per day). This would allow for moderate growth before needing expansion. Council decided to build a smaller plant with 2 units, aiming to add a 3^rd unit later, at a higher overall cost. A “latent capacity” study appeared to justify this decision but assumed only one dwelling per section and relatively low density. In reality, numerous sections carried multiple dwellings and cross-leases, and the study did not analyse existing wastewater connections in the Council's own rating database. Engineers’ warnings about "underdesigning" the wastewater system were brushed aside.

Wastewater pipelines under strain

The amount of wastewater needing treatment has increased at least 70% in 10 years due to new connections, and much of the treatment capacity has been taken up. New buildings and new connections continue to be added year by year. Capacity is also consumed by problems in the sewage pipes. Treatment plants are intended to treat what we flush — not what falls from the sky. But stormwater is able to enter the sewage pipes from illegal roofwater connections and old leaky pipelines.

Amounts flowing into the treatment plant sometimes exceed the safety level identified by Beca’s engineers. After heavy rain, the total volume entering the plant can double or even triple. This problem will only become worse with heavier, more frequent downpours expected in the future.

Excessive inflows also have environmental implications. When the treatment plant is overloaded, its UV system is unable to kill some harmful organisms. The plant discharges into Waitangi Wetlands, a special area with threatened native species such as mudfish. The council is required to comply with a NRC consent. But the consent conditions are lax, and compliance is usually achievable on paper, giving an impression that the system is OK.

Upgrading issues

The Council sewage system needs to be upgraded sooner than expected. This will require expensive redesign and retrofits for sub-catchments, pump stations and pipeline sizes, as well as additional capacity in the treatment plant in the short term. Engineers have warned that retrofitting and upgrading an under-designed installation has a very high cost. Future growth will require more expense, more treatment units and an almost complete rebuild of the underground network of pipes and pump stations. Who will pay for all this?

Unfortunately, the Council had stopped ‘development contributions’ in 2015, worsening the infrastructure funding backlog. For years, community groups pressed for a policy reversal, and, very belatedly the Council has restarted the collection of contributions this year. However, the amount accrued by that method in the future will be a small fraction of the total funding needed for essential infrastructure.

New approaches

A District Plan does not specify Council spending — that is the role of the Long Term Plan — but it can and must control the staging, scale and location of future development to fit Council’s ability to provide infrastructure. Vision Kerikeri believes that future growth needs to be managed in stages and firmly linked to infrastructure capacity, supported by reliable information data and verification, not assumptions.

We also need to look at additional ways to get essential infrastructure. One of many reasons Vision Kerikeri supports development on the KFO site (between SH10 and the golf course) is because the developer has offered to provide all the infrastructure, including a wastewater treatment system for that area. Council also needs to consider less expensive and more culturally acceptable and environmentally friendly technology for sewage treatment, e.g., electro-coagulation – this should be considered in all future Council upgrades across the district.

Help us make the case for our town

We continue to make the case for appropriate growth and a town that functions well for our community. For PDP mediation and planning processes, we need input from expert planners and other specialists, but expert hours cost around $150 per hour. We have a Fighting Fund target of $12,000: that's 80 hours of professional analysis and representation. Every hour you fund goes directly to the evidence; donors will be acknowledged on our website and Facebook page (unless they prefer to be anonymous).