Information about growth modelling for residential and business development across the district

Population growth has been occurring throughout the Selwyn district, but the lion's share is in the 'commuter belt', close to Christchurch, and is addressed by the Greater Christchurch Partnership. This high-growth area includes West Melton, Rolleston, Lincoln, Springston, Prebbleton, Tai Tapu and many rural "lifestyle blocks".

Stats NZ has good population statistics, including Population Estimates and Population and Household Projections.

Growth Modelling

The Council has been maintaining a Growth Model to predict future residential and business development across the district. The growth model comprises two parts, a Residential Growth Model (click here for the report), and a Business Growth Model (click here for the report).

Our Growth Model spatially identifies capacity by analyzing a variety of data and making assumptions around the type of new development needed.  Growth modelling helps us plan to ensure there is sufficient infrastructure and zoned land in the right location at the right time.

Growth Model Data Inputs

The following data is used as an input into our Growth Model:

Growth Model Assumptions

The Formative report outlines the modelling process we follow for both the Business Growth Model and the Residential Growth Model (click here for the report).  The assumptions made in our Growth Model are:

  • The Site sizes that relate to what the District Plan enables (e.g. Plan-enabled) and what could be reasonably expected to be realized, which is based on recent subdivision consent and market expectations.
  • The Profit margins for feasibility calculation
  • The Population and household projection assumptions
  • The Dwelling utilization
  • What sites to include as developable urban land and property (e.g. not council owned)
  • The Long-term changes in construction costs and house sales price

Outputs

The following spreadsheet [XLSX, 172 KB] and report contain the outputs of the model following the update in February 2023.  We are in the process of updating the model again and expect to have further updates completed in January 2026.

If you have any questions, please contact the Duty Planner on Phone 0800 SELWYN (735 996) or email contactus@selwyn.govt.nz