Maximizing Affordable Housing with Minimal Environmental Impacts for Christchurch, NZ

Kāinga Ora – Homes and Communities, New Zealand’s leading agency for public and affordable housing, has partnered with Christchurch City Council (CCC) on a pilot project to address a critical challenge: accelerating build-ready land availability for housing while minimising strain on infrastructure and environmental risks. With Christchurch projected to grow by over 20% in the next 30 years, CCC must manage its wastewater network to enable sustainable urban development. This initiative aligns housing intensification with infrastructure resilience and environmental stewardship.

Using a first-of-its-kind approach in New Zealand, intelligent algorithm optimisation evaluated urban growth alternatives to identify areas that support housing intensification with minimal environmental and infrastructural impact. Optimizer-ICM™ was used to simulate thousands of development scenarios within the hydraulic model using a 2-year representative design storm, incorporating CCC’s growth projections and landuse density yields. Intelligent algorithms assessed hydraulic performance against baseline conditions, quantifying overflow volumes and freeboard reductions to maximise development potential while minimising impacts on the network.

The analysis demonstrated that existing wastewater capacity could support up to 35,000 additional people (approximately 10% growth) with negligible increases in wastewater overflows and minimal network impact. Results, visualised via Power BI and ArcGIS, provided actionable insights to inform CCC and Kāinga Ora in prioritising projects and approving developments aligned with sustainable growth objectives.

This system-wide optimisation offers a preliminary guide to areas likely to have minimal impact on wastewater overflows, helping decision-makers balance housing intensification with network and environmental considerations. The innovative application of intelligent algorithms, cloud computing, and data analytics underscores the transformative potential of effects-based planning to support equitable, sustainable urban development. Kāinga Ora’s announcement of a new development on land recommended within this study further highlights the usefulness of its findings