Potomac - 3. Great Falls (Fish Ladder)

Potomac, Maryland, US


3. Great Falls (Fish Ladder)

Usual Difficulty IV-V(V+) (varies with level)
Length 0.6 Miles
Avg. Gradient 100 fpm
Max Gradient 200 fpm

Gauge Information

Name Range Difficulty Updated Level
usgs-01646500 3.50 - 4.70 ft V+ 00h36m 5.89 ft (too high)

River Description

The Fish Ladder is the river left side channel of Great Falls along the C&O Canal towpath on the Maryland side. It is the largest of a network of small parallel channels that form Olmstead Island, carrying perhaps 10- 20 % of the total flow of the Potomac River. It was often thought to be easier than Great Falls proper, but still deserves a solid class V rating due to the difficulty of the crux and the nasty conditions of the riverbed, which shifts frequently. This channel was altered in 1892  By the Army Corps of Enginners and has been deteriorating ever since, leaving sharp rocks, chunky 'Cheese Grater' concrete, steel beams, rebar, railings from a washed out bridge and other hazards than can seriously injure an upside down boater, and tear holes in a plastic kayak. The name fishladder primarily applies to the far river left channel where the concrete slides define the crux on the run. The smaller Tight Quarters, Bridge Channel, and Olmstead channel break off to the right before the 1st slide.   The 'Back Canyon' is the narrow box canyon that splits off to the right just before the footbridge, with small rock islands and the 'Bitch Monkey" drop separating them. 

 Paddling the Fish Ladder, you are also in full view of the Park visitors, and history has proven that folks will dial 911 if they see anything other than clean lines, so don't screw up! The hazards are unfortunate but on the correct line at the correct water levels its great fun and probably won't damage your boat. All of the rapids, with the exception of the last slide, can be pre-scouted from the trail network along the C&O Canal Towpath and the footbridge leading to the Great Falls overlook. This channel collects wood  like the NSA collects phone records..... so be sure to look first.  Logjams move annually, and several riverbed changes have occured in recent years. most notably the 3rd Slide kicking harder towards The Bitch Monkey, and new rocks in the pinch of the Back Canyon. 

To learn more about the history of the Fish Ladder, read this description on the C&O Canal website.

Related reaches: Great Falls (Center Lines), Great Falls (MD Lines), and Great Falls (VA Lines).

Permit Information

Running Great Falls is legal but you should be experienced and knowledgeable about the river your entering. Great Falls is a Highly visible rapid and your lines will be curiously critiqued by the other park visitors. Unfortunately, It is not legal to put in above the Falls on the Virginia side.

StreamTeam Status: Not Verified
Last Updated: 2016-10-03 09:53:02


Stream team editor

Rapid Summary

Mile Rapid Name Class Features (Legend)
0.1Aquaduct DamIVPutin Portage Hazard Waterfall
0.2Bridge Channel (overflow)5.1Portage
0.3Tight QuartersIVPutin Playspot Photo
0.3First SlideIVPlayspot Photo
0.4Second SlideVAccess Hazard Photo
0.4Back Canyon5.1Hazard Waterfall Photo
0.4Third Slide5.1Access Portage Photo
0.4Bitch Monkey5.2Hazard Waterfall Photo
0.4Fourth SlideIV+Putin Photo
0.5Carving BoardIV+Access Hazard
0.5Fifth Slide5.0Hazard Waterfall Photo

Rapid Descriptions

Aquaduct Dam (Class IV, Mile 0.1)

This old 5-10 foot stone dam  is easy to boof but it does dovelop into a dangerous hole at high water. the best area is 10 -100 yards from the pump house, depending where you are going. below the Dam the river splits around Olmstead and Falls Island. 

Bridge Channel (overflow) (Class 5.1, Mile 0.2)

also called Flood Zone, this channel splits off to the river right of the Main Fish Ladder below the aquaduct dam. Not much water goes through here until it gets above 5 feet, and there are TONS OF HUGE TREES. generally there is a way to paddle around the logjams to access the sweet slides under the Walkway but its not a good idea to paddle into this channel without a guide.

Tight Quarters (Class IV, Mile 0.3)

Tight Quarters

Tight Quarters
Photo taken 09/23/11 @ 3.60 ft

Tight Quarters is a more natural and relatively mellow alternative to the 1st and 2nd Slide above 4 feet, But it dumps back into the main Fishladder directly above the Back Canyon where a ferry must be executed. It  frequently collects wood but otherwise is a pleasant warm up. T.Q. splits off to river right after the Bridge Channel but before the 1st slide. The entry drop can be run either side, then there is a pool where the channels briefly rejoin between slides 1+2. Continuing on through T.Q. there is a nice 3 foot ledge to boof.  Tight Quarters ends and rejoins the main fishladder channel below the Second Slide directly above the steep stuff. A tricky ferry must be made here to avoid washing into the Back Canyon.

First Slide (Class IV, Mile 0.3)

Slide 1

Slide 1
Photo of Chris Preperato by Matt Fiteny taken 09/22/11 @ 3.60 ft

The First Slide is fairly straightforward  fun move. Punch the hole on the left or right. Below here the Fish Ladder rejoins Tight Quarters briefly. The main channel moves quickly to the left towards the steep section

Second Slide (Class V, Mile 0.4)


Photo of Sam Burk by Art Barket taken 12/02/12 @ low runnable level

The Second Slide has a boxed in hole with recirculating eddies on either side. It would be a bad place to swim because the outflow pushes toward the steepest and most continuous section of the Fish Ladder. Fortunately there is a flushy spot in the center. Get some speed going above the slide, keep your bow up, pointed straight, boof and keep your weight forward. A good place to set safety.

Back Canyon (Class 5.1, Mile 0.4)


Photo of Jason Beakes by Maggie Snowel taken 12/02/12 @ a good level

A  quick series of four difficult, stair-stepping drops with all the gradient of the Third and Fourth slides but no eddies in-between. The entrance is choosy but a couple of large slabs of rock fell in 2010 and made a new ledge under the footbridge just above the narrow pinch. Watch out for the table saw fin rock on the right. The next drop has A gnar pocket hole in the center and is usually boofed far right, but left goes too. Try to get left for the last drop. Then a 2 foot ledge at Fishladder confluence.  Optimal around 4.0,  High water will often deposit trees in the pinch

Third Slide (Class 5.1, Mile 0.4)


Photo of Sam Burk by Art Barket taken 12/02/12 @ low runnable level

Below the Second Slide a footbridge crosses the Fish Ladder and the current splits again around a bridge pylon. To the left of the pylon is the Third Slide of Fishladder,  and tumbling over an artificial ledge to the right is the Back Canyon. If you run the Third Slide it is critical to keep left angle as you either punch through the V wave, or take the safe line on the far left. The primary danger is getting deflected to the right over 'Bitch Monkey', a chaotic drop into the Back Canyon.  

Bitch Monkey (Class 5.2, Mile 0.4)

super low decent of Bitch Monkey

super low decent of Bitch Monkey
Photo of Sam Burk by Art Barket taken 12/02/12 @ a good level

This chaotic drop connects the third slide to the Back Canyon, but it has an irregular lip and a shallow landing.   It can be run well, but unfortunately it’s frequently run by accident. Formerly, there was an eddy or logjam above the slot but in recent years, rocks have shifted and much more water is rushing towards the dividing rock, and to the right over Bitch Monkey, which is now certainly in play.

Fourth Slide (Class IV+, Mile 0.4)

Limbo Rapid

Limbo Rapid
Photo taken 09/23/11 @ 3.60 ft

After the Third Slide there is a small pool on the left above a boulder Rapid called 'Limbo' which has some fun eddies to catch but often collects wood. This leads you directly onto the Fourth slide, which is best entered in the middle pointing left. This is the shallowest slide and you will probably be scraping a little, even at high flows these days. Most people catch the big eddy on the left below the Fourth Slide and then ferry to the right, but you can also make the turn directly into The Carving Board, but there are several submerged rocks that make this a tricky race line. The Third/Fourth Slide sequence is the most technical part of the Fishladder proper.

Carving Board (Class IV+, Mile 0.5)

This is the junky rapid Below the 4th slide that rejoins with the Back Canyon. Very large trees tend to pile up here so keep eyes open. From the eddy below the 4th slide you'll have to pick your way through some rocks then scrape over a chunk of Concrete into a fun wavetrain with more fun eddies on the sides. These waves lead directly into the 5th slide

Fifth Slide (Class 5.0, Mile 0.5)


Photo of Mark Loeffler by Brett Mayer taken 12/03/12 @ low runnable level

This is the biggest and steepest slide and has a great horizon line overlooking S-Turn. There is a nice setup eddy above it on the right where you can boat scout the hole. From there you can peel out, come screaming down the slide, and try to punch the hole on the left or right. If you were to get stuck in the hole it would be very violent and shallow. Several boats and paddles have been broken here, and the powerful seams downstream make it an unpleasant place to swim.  A fun alternate line is to do the “Skirtless Boof” on the left and then either take out or enter the slide 1/3 of the way down. It is possible to do laps on this slide by walking up the concrete on the right bank. Paddle over to Sandy Beach and carry back up the Towpath to get back to the top.

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