Cotter River
The Cotter River rises below Mount Scabby in the Scabby Range at the southern end of the Brindabella Ranges, and flows north for about 76 km through Namadgi National Park to its confluence with the Murrumbidgee River at Casuarina Sands. Along with the Queanbeyan River, it’s one of the two rivers that supplies drinking water to Canberra and Queanbeyan, held back along the way by the Corin, Bendora and Cotter dams.
Description
The Cotter drains a catchment of about 483 km², almost entirely within Namadgi National Park and largely unmodified by farms, houses or development — a rarity this close to a capital city. It’s an upland cobble- and gravel-bed river, running through steep, granite- and shale-based terrain bound by the Tidbinbilla Range to the east and the Brindabella Range to the west, with its course through the lower catchment shaped by the Cotter Fault. The catchment still bears the scars of the 2003 bushfires, which triggered major sediment runoff into Bendora and Corin dams and prompted significant remediation work in the years since.
Habitat and ecological role
Because the catchment is so tightly protected — no farms, no houses, restricted recreation access — the Cotter carries some of the cleanest water reaching Canberra’s taps, and the largely intact forest cover through Namadgi supports a river system still close to its natural state. The Cotter is also home to a trout fishery, with sections of the river open to anglers in season.
Whitewater paddling
I love this river — it offers exciting and challenging whitewater paddling, and the stretch below Bendora Dam is genuinely something special. The section between Bendora Dam and Vanities Crossing is what I’d call unicorn water: a very rare and elusive paddle, 16 km of fast-moving water through innumerable grade 2+/3 rapids, running through remote and largely inaccessible terrain for most of the run. Flow-dependent and hard to time, but when it’s on, it’s one of the best days you can have on a river in this region.
Position in this vault
The Cotter River is the primary river draining the eastern flank of the Brindabella Ranges toward Canberra, running through the same Namadgi National Park country referenced elsewhere in this vault’s coverage of the range’s alpine and wet sclerophyll forest zones.