About the area
The Main integrated system sources Bulk water supply from Melbourne Water, Rosslynne Reservoir system, Merrimu Reservoir, Djerriwarrh Reservoir, Kerrie Reservoir, Garden Hut Reservoir, Campaspe Reservoir, Campaspe River tributaries, Mount Macedon storages and tributaries (indirectly supplemented from integrated systems in times of drought), as well as groundwater.
The Main integrated system services the townships of Sunbury, Gisborne, Bacchus Marsh, Diggers Rest, Riddles Creek, Macedon, Melton, Mount Macedon, Romsey, Woodend and Lancefield.
This system has water treatment plants in Melton, Gisborne, Romsey, Lancefield and Woodend, producing potable water for urban use.
This system is supplied by Greater Western Water.
Water balance
The table below shows the total volumes of water supplied from water resources in the Main integrated system in 2022-23.
Table 1: Water balance, Main integrated system
| Water account component | 2021-22 (ML) | 2022-23 (ML) |
|---|---|---|
| Volume in store | ||
| Start volume in store | 2,337 | 2,177 |
| End volume in store | 2,195 | 2,324 |
| Change in store | (142) | 147 |
| Inflows | ||
| Inflow from surface water | 3,656 | 3,574 |
| Inflow from groundwater | 0 | 83 |
| Inflow from distribution system | 15,357 | 15,272 |
| Inflow from recycled water | 0 | 0 |
| Rainfall | 379 | 526 |
| Unattributed inflows | 0 | 0 |
| Total inflows | 19,392 | 19,455 |
| Outflows | ||
| Deliveries | ||
| Urban residential | 13,173 | 13,512 |
| Urban non-residential | 2,306 | 2,390 |
| Passed to other systems | 0 | 0 |
| Total deliveries | 15,479 | 15,902 |
| Losses | ||
| Evaporation | 195 | 462 |
| System losses 1 | 3,859 | 2,944 |
| Total losses | 4,054 | 3,406 |
| Other outflows | ||
| Unattributed outflows | 0 | 0 |
| Total outflows | 19,533 | 19,308 |
| System efficiency | ||
| Distribution system efficiency (%) | 79% | 82% |
