Catchment sizes

Below are figures for catchment sizes for many of the more well known canyons. Catchment sizes are one input into the risk of a canyon flash flooding or the water level rising dangerously. In conjunction with other information it may be useful for people considering canyoning during inclement weather or when rain is forecast. Please note that it is not an endorsement or recommendation of canyoning during the rain. The Canyoning Code of Ethics states "Avoid canyoning if rain is forecast or if the weather looks changeable". If you are unfamiliar with a canyon then you should certainly not visit in those conditions.

The 'entry' and 'exit' sizes below are where parties would generally enter the creek (which is typically not far upstream of the canyon section) and exit the creek (usually just downstream of the canyon section). Some creeks complicate things with multiple sections, or major discontinuities as large tributaries enter. Also canyons that exit into larger creeks which are also canyons - such as the Wollangambe or Bungleboori - are a little complicated! I have tried to comment appropriately.

Also keep in mind that even if a canyon may have a small catchment, the only way out may be via a canyon or creek with a much larger catchment! The bottom line is that as usual, you need to exercise due caution and judgement any time you enter a canyon when rain has fallen or is expected to fall.

Wolgan
Canyon	Area (km2)	Comment
Starlight	1.61	entry
	1.90	Upside-down junction
	3.26	Fireball junction
Devils Pinch	0.14	entry
	0.91	exit
Pipeline	0.74	start of lower canyon section
	0.92	exit
Firefly	0.96	entry
	3.60	exit
South Wolgan
Canyon	Area (km2)	Comment
Tiger Snake	0.16	entry
	0.39	exit
Surefire	3.03	entry
	3.23	just before exit canyon
	5.38	end of canyon
Heart Attack	7.12	entry
	7.87	just before exit canyon
Galah	2.02	entry
	2.93	exit near Rocky Creek
Closet	0.35	entry
	0.59	Rocky Creek junction
Breakfast Creek	0.27	entry
	0.63	Rocky Creek junction
Coachwood	0.67	entry
	1.03	Rocky Creek junction
Twister	2.16	entry
	2.25	Rocky Creek junction
Rocky Creek	18.82	entry
	19.07	Budgary Creek junction
	33.96	normal Rocky Creek exit gully
Bungleboori
Canyon	Area (km2)	Comment
Hole-in-the-Wall	1.22	entry
	2.05	Dingo Creek junction
Dingo Creek	31.8	Hole-in-the-Wall junction
Wollangambe
Canyon	Area (km2)	Comment
Waterfall of Moss	0.08	entry
	0.50	Wollangambe junction
Whungee Wheengee	2.36	entry
	2.88	Wollangambe junction
Water Dragon	0.80	entry
	1.16	Wollangambe junction
Horseshoe	0.77	entry
	0.81	Wollangambe junction
Geronimo	1.63	entry
	1.80	Wollangambe junction
Why Don't We Do It In The Road?	1.66	entry
	2.13	Wollangambe junction
Upper South Bowens	0.58	entry
	2.71	below Corkscrew junction
	3.78	just above Range Creek junction
	7.95	exit
Lower North Bowens	7.83	entry
	8.27	just before South branch joins
Carmarthen Labyrinth
Canyon	Area (km2)	Comment
Claustral	0.78	entry
	2.63	just above Ranon junction
	5.32	just below Ranon junction
	5.66	just above Thunder junction
Ranon	2.03	just below Mistake Ravine junction
	2.69	just above Claustral junction
Thunder	4.73	entry
	5.11	just above Claustral junction
	10.77	just below Claustral junction
	11.29	just above Rainbow Ravine
North Grose
Canyon	Area (km2)	Comment
Yileen	0.78	entry
	1.08	exit
Better Offer	0.20	entry
	0.34	exit
Birrabang	1.15	entry
	3.44	exit
Wotta	0.19	entry
	0.47	exit
Dalpura	0.97	entry
	1.33	exit
Koombanda	1.31	entry
	3.77	exit
South Grose
Canyon	Area (km2)	Comment
Fortress	2.01	entry
	3.67	exit
Mt Hay	4.22	entry
	5.08	exit
Jugglers	0.43	entry
	0.54	exit
Arethusa	21.7	entry (note that if the Cascade Dams are full, then it's about 24.0)
	22.0	climbing exit
Jamieson Valley
Canyon	Area (km2)	Comment
Empress	2.71	entry
	2.93	exit