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 |
| 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 | |
| Dalpura | 0.97 | entry |
| 1.33 | 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 | |
| Jamieson Valley | ||
| Canyon | Area (km2) | Comment |
| Empress | 2.71 | entry |
| 2.93 | exit | |