Blackmore River

Blackmore River flows into Darwin Harbour close to Darwin in the Northern Territory of Australia.

Course
The headwaters of the river rise at an elevation of 21 m on the Wild Horse Plain and flow northwards past Tumbling Waters and through the Blackmore River Conservation Reserve. The river discharges into Darwin Harbour at Middle Arm.

The Elizabeth River and Blackmore River catchments together occupy an area of 1150 km2, with the Blackmore catchment occupying 848 km2.

The estuary formed at the river mouth is tidal in nature and in near pristine condition.

Climate
The climate of the Blackmore River region is monsoon tropical with two distinct seasons: the Dry and the Wet. The Dry lasts for 6 months between April and September with an average rainfall of 24 mm, whereas the Wet lasts between October and March with an average monthly rainfall of 254 mm/month (according to the Bureau of Meteorology, 1999). The majority of the rain falls between December and April. Runoff varies between 250–1000 mm.

Peak flow for the Blackmore River occurs in February with 605Ml/day, after which it slowly decreases until July when there is no freshwater input into Darwin Harbour until the onset of the following wet season (Padovan 1997). Cyclone frequency is low to moderate.

Water quality
The water quality at the upper estuary and freshwater monitoring sites of the Department of Land Resource Management of the Northern Territory Government was 2011 in moderate condition.

Geology
The underlying lithology is dominated by Permian siltstones and sandstones.