Developing a strategy to replace an aging wellfield

Gear Island and Waterloo Wells Replacement

When it comes to water supply, only three things matter—access, reliability, and safety. A large part of the Wellington Region’s water supply is provided by eight wells located in the Lower Hutt Valley sourced from the Waiwhetū Aquifer. These existing bores are 30 to 40 years old and nearing the end of their economic life.  

We developed a three-staged approach for delivering this project to ensure optimal results. Stage 1 was to complete the design, procurement, and construction monitoring for installing 15 monitoring bores across the Hutt Valley. This was to collect geological, hydrological, and hydrogeological information to understand the aquifers’ behaviour better and update the Hutt Aquifer Model (HAM) from HAM3 to HAM5. This model will be used to develop the wellfield replacement strategy for the Stage 2 and 3 projects. Stage 2 of the project is the installation of two new water supply wells to provide operational resilience to the network, and stage 3 replaces the existing eight wells with a resilient network of safe drinking water.

The first stage project presented complexity with eight different work sites, each with its own characteristics and requirements. The team worked to maintain effective communication with more than 15 stakeholders across the region, including councils, landowners, and industry experts. When this replacement is implemented, the Wellington Region’s new well network will provide reliable water for years to come.