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Merrimu Reservoir


The reservoir was constructed in three stages from 1969 to 1986 and has a capacity of about 32,000 ML.

The reservoir has a small natural catchment area, so to supplement its storage ability, two small diversion weirs and two tunnels from neighbouring catchments were built. These works and the subsequent raising of the reservoir embankment form the three main stages of the Merrimu Reservoir construction.


The water in the reservoir is primarily used to supply drinking water to Melton and Bacchus Marsh with the remaining used for irrigation in the Werribee Irrigation District.

Merrimu Reservoir provides better management and regulation of water flows in the Werribee Basin, consequently increasing the security of supply to Werribee and Bacchus Marsh irrigation districts, urban water and industrial supplies in the Melton and Bacchus Marsh areas.

Capacity 32,516 ML
Dead storage 335 ML
Surface area 420 ha
Full supply level 174.1 m AHD
Catchment area 85 km22
Maximum height 45.3 m
Length 400 m
Crest length 30 m
Discharge capacity 26,000 ML per day

Merrimu Reservoir is located on Pyrites Creek, a tributary of the Werribee River, 10kms north-east of Bacchus Marsh and approximately 50kms from Melbourne – VicRoads Reference Map 328 J6.

Please check the water levels before planning a day out at the reservoir!

Southern Rural Water acknowledges and recognises Aboriginal people as the Traditional Owners and Custodians of the land and waters on which we work and live, and we respect their deep and ongoing connection to Country. For more about the First Nations peoples on whose Country we work, click here.