Cataract Canyon — September 2020

Low-water Cataract Canyon dory trip at 4,692 CFS with Lake Powell at 3,597 ft. Five days from Potash with Greg and Charlie Madsen. Big Drop 3 proved unavoidable at this level — rock hit damaged the chime front right regardless of line. Rapid 5 hesitation resulted in a high side. Conclusion: avoid Cataract in the dory at flows this low.

5 days 4,668 cfs 3 people dory

Conditions

4,692 CFS at Cataract; 2,600 CFS at Potash; 2,000 CFS on the Green River — low water

5 days

4,668 cfs

16 ft/mi

1 boats

Day 1 9-15-2020

Day 1

4,900 cfs (USGS daily mean), water 68°F | Moab, UT: 48–92°F

Day 2 9-16-2020

Day 2

4,740 cfs (USGS daily mean), water 68°F | Moab, UT: 50–91°F

Day 3 9-17-2020

Day 3 — Big Drops

4,770 cfs (USGS daily mean), water 67°F | Moab, UT: 62–91°F

Ran the Big Drops at low water. Normal run in Big Drop 3 results in a rock hit no matter what — damaged chime front right. Rapid 5 hesitation resulted in a high side. Better to avoid this level in the dory; not sure you could clean BD3 without a rock hit.

Day 4 9-18-2020

Day 4

4,700 cfs (USGS daily mean), water 67°F | Moab, UT: 76–91°F

Day 5 9-19-2020

Day 5 — Take-Out

4,610 cfs (USGS daily mean), water 67°F | Moab, UT: 55–91°F

Normal run in Big Drop 3 results in a rock hit no matter what line is taken at this flow. Damaged the chime front right on the dory.
Hesitation in Rapid 5 resulted in a high side. Commitment to the line is critical at low water.

Lessons

Big Drop 3 at ~4,700 CFS: cannot clean this rapid in the dory without a rock hit. The normal run results in rock contact regardless of line choice.
Rapid 5: hesitation leads to a high side. Commit to the line.
Avoid Cataract Canyon in the dory at flows below ~5,000 CFS. Not enough water to clear Big Drop 3 without hull damage.

Gear

Dory sustained chime damage front right in Big Drop 3. Repair needed post-trip.

Data

Colorado at Potash: 2,630–2,900 cfs (avg 2,708)

Green at Mineral Bottom: 1,940–2,000 cfs (avg 1,960)

Combined: 4,570–4,870 cfs (avg 4,668)

Lake Powell: 3597.72 ft at launch (3597.27–3597.72 ft during trip). USBR RISE API — Lake Powell at Glen Canyon Dam

Weather: Moab, UT, 48–92°F. NOAA GHCN-Daily

Field Sources

Evidence behind the claims on this page — agency rules, maps, gauges, books, and field notes.

Rapids

book-excerpt Cataract Canyon (Webb / Belnap / Weisheit) — Selected Pages — University of Utah Press (2007)
book RiverMaps Guide to the Colorado & Green Rivers in the Canyonlands of Utah & Colorado — Tom Martin, Duwain Whitis (2016)