Adelaide's Water Supply: Mount Lofty Ranges Reservoirs and Desalination

Adelaide, South Australia's capital (pop. 1.4M), relies on a dual-source system shaped by its Mediterranean climate and variable rainfall.

Primary Source: Mount Lofty Ranges Reservoirs (~70–80%)

• Catchment: 1,500 km² of forested hills east of the city.
• Major Reservoirs (10 total):
  • Happy Valley (largest, 12.6 GL) – Onkaparinga River
  • Mount Bold (45.9 GL) – Onkaparinga (upstream)
  • Myponga (26.8 GL) – Myponga River
  • South Para (45.3 GL) – South Para River
  • Kangaroo Creek (19.1 GL) – Torrens River
  • Millbrook (16.5 GL) – Torrens River
  • Hope Valley (2.9 GL) – Torrens River
  • Little Para (20.8 GL) – Little Para River
  • Barossa (4.5 GL) – South Para River
  • Warren (4.8 GL) – Warren River
• Yield: Highly variable (droughts: 2006–09, 2017–20). Climate change reducing reliability.

Supplementary Source: Adelaide Desalination Plant (ADP) (~20–30%)

• Location: Port Stanvac (Lonsdale), 25 km south.
• Capacity: 100 GL/yr (expandable to 200 GL) – ~50% of annual demand.
• Technology: Reverse osmosis (SWRO); 100% renewable-powered (via SA grid).
• Operation: Base-load (20–30 GL/yr) + drought ramp-up. Cost: ~$1.2M/week at full capacity.

Other Inputs

• River Murray: Via Morgan-Whyalla & Mannum-Adelaide pipelines (minor, emergency).
• Stormwater / Recycled: Growing (e.g., Virginia Pipeline Scheme – 20 GL/yr for horticulture).
• Groundwater: Limited (T1/T2 aquifers) – managed to prevent saltwater intrusion.

Governance

SA Water (state-owned) manages supply; Department for Environment & Water sets policy. Water Security Plan targets climate-independent sources (desal, recycling) for 85% by 2050.