Readiness Index for Future Urban Growth Areas

The Readiness Index provides a simple comparative measure of how well each Future Urban Growth Area is currently serviced by existing water infrastructure. Its purpose is to help visualise and differentiate growth areas based on the extent and strength of their surrounding water network. The index is calculated offline using only geometric attributes of water mains — specifically their length and diameter — to quantify both coverage (network density) and capacity (pipe size). Each area’s score is then normalized between 0 and 1, where higher values indicate a more developed or better-serviced area.

In a broader assessment, true readiness would also depend on additional factors such as pressure zones, material type, age, condition, and planned upgrades. However, due to data limitations, this first version focuses on these two core, measurable indicators to illustrate a basic readiness pattern across the metropolitan area.

Method

• Network density = total pipe length inside area / area size (km/km²).
• Diameter strength:
  • p90_diam = length-weighted 90th percentile diameter (mm).
  • large_share = share of pipe length with diameter ≥ 200 mm (0–1).

Formula

readiness = 0.5 * norm(density)
         + 0.3 * large_share
         + 0.2 * norm(p90_diam)

Table columns shown below

• Area Name: from polygon attribute name.
• Area ID: polygon key used to join results (area_id).
• Readiness: 0–1 score from formula above.
• Pipe km: total water main length within polygon.
• Density: pipe_km / area_km².
• p90 diam (mm): length-weighted 90th percentile diameter.
• ≥200mm share: proportion of pipe length ≥ 200 mm.