Mersey – Union Bridge to Kelly’s Cage Rd Bridge (Alum Cliffs Run)

Canoe Tas Inc


Mersey River

Union Bridge to Rogers Bridge (Alum Cliffs)


Distance: 24 km.
Average Grade: 5 m/km.
Peak Grade: 10m/km through Alum Cliffs.
Difficulty: Grade 3-4-5.
Paddling Time: 3-5 hours.
Entry Point: The Union Bridge on the Union Bridge Rd (C137) (Grid ref. 444 037). (An alternate entry is at the Limestone Quarry off Den Rd and Big Den Rd, Mole Creek, which cuts out 2 kms of flattish water.)
Exit Point: Kelly’s Cage Rd Bridge (formerly known as Rogers Bridge), off Dynan’s Bridge Road, (C159) near Weegena (Grid ref. 560 079).
Water Level:

  • Although this section can be pack-rafted or inflatable kayaked on environmental flow released from the Parangana Dam mini-hydro station, for normal kayaking either very heavy local rain or Parangana Dam spilling by 20cm+ is needed.
  • An ideal height is 30-50cm spilling over Parangana Dam (factoring in an approximately 24hr delay between Parangana and Alum Cliffs) or above 0.75m at Liena and/or above 1.5m at Kimberley.
  • At higher levels the wave size increases and the water is pushier but in some respects less technical.
Tasmap: 1:100 000 Mersey, Forth.
Shuttle: Either via Mole Creek, Dunorlan and Weegena (sealed road) or Dynan’s Bridge Rd and Union Bridge Rd (75% unsealed but slightly shorter).
General Description: This trip has some of the most impressive cliffs and gorge scenery in Tasmania as well as approximately 15km of very pleasant, technical grade 3 water and one easily portaged grade 4-5 rapid (depending upon level), interspersed with grade 2s and pools. It is highly regarded for its scenic beauty and enjoyable paddling.

The first 6 km is fairly flat with a few small shingle rapids, mostly grade 1-2, then the river enters Alum Cliffs beneath the Alum Cliffs lookout. The first gorge is fairly fast with large standing waves and a few stoppers, grade 3.

At the end of this first section of rapids, the river makes a sharp turn around an impressive rock column rising 20-30m. out of the river. Not long after this the main gorge is entered with the only portage on the trip due to a nasty (Grade 4 up-to grade 5 depending on the level) section of water. Portage on the left (beware the very slippery limestone slabs) and re-enter the river after the main drop in this rapid, or continue another 100m downstream to avoid the bottom section of the rapid. The bottom section involves a narrow, twisty, boily rapid next to the cliffs on the right followed by a hard (90+ degree) left turn to avoid a large drop and retentive pour over stopper on the right which can span 3/4 of the river at higher water levels. This can be inspected from the bottom of the portage.

After another kilometre or so of grade 2-3 water the river enters the “chasm” – a still, deep gorge which opens out into a large pool. This gorge is very reminiscent of the Irenabyss on the Franklin River. After more grade 2 and some technical grade 3 rapids and nice wave-chains the river then opens out. Beware of logs and trees in the first wide shingle rapid where the river splits into two or three channels as this point is known for accumulating trees in awkward spots and for willow re-growth. Both the left and right channels can be paddled.

From here the river is interspersed with grade 2 to easy 3 rapids as it flattens through farmland to the finish at Kelly Cage Rd Bridge.

Updated 2018


Mersey - Alum Cliffs Chasm
The Chasm – Alum Cliffs
Mersey - Alum Cliffs - Portage Rapid
Mersey – Alum Cliffs – Main Drop of Portage Rapid 2018