Potomac - 3. Great Falls (Center Lines)

Potomac, Maryland, US


3. Great Falls (Center Lines) (streamers)

Usual Difficulty V+ (for normal flows)
Length 1 Miles
Avg. Gradient 100 fpm
Max Gradient 500 fpm

Center Lines

Center Lines
Photo of Greg Morrison by Thilo Rusche

Gauge Information

Name Range Difficulty Updated Level
usgs-01646500 3.30 - 3.95 ft V+ 00h38m 4.65 ft (too high)

River Description

Great Falls of the Potomac River is a major set of rapids located about 15 miles upstream of Washington, DC. The main Falls lines drop fifty feet in one-tenth of a mile, creating a Class V+ set of waterfalls. In addition, a portion of the river flows around Olmstead Island in a channel called the Fish Ladder (additional channels flow at higher water).

Center Lines (Grace Under Pressure/ Fingers) It is a spectacular cataract with some sweet lines, but  when running it - you are on the fringe of a massive channel surrounded by deadly sieves, huge holes,  and treacherously slippery rocks, and if you don't know it - its easy to get disoriented. There were major changes in Spring 2018 so everyone should scout because the ideal flows have changed. It is not obvious how to get out to scout if you haven't been there before, a guide is mandatory. Even the sleeper pourover in the class 3 approach rapid above the falls can dish out a beating at these levels, and all the other drops to the river left of Grace Under pressure and river right of Pummel are extremely seivey and dangerous. A substantial amount of the flow goes towards the Subway sieve or into the Maryland Lines, http://www.americanwhitewater.org/content/River/detail/id/5553  which will be stompy. Swimming anywhere near the Center lines is a life threatening mistake that usually requires an elaborate rescue in full public view. There have now been 2 fatalities here of experienced kayakers who had run the lines before, most recently in July 2013. http://www.americanwhitewater.org/content/Accident/detail/accidentid/3743/.  Know your limits out here and don't come without a guide and very experienced friends. Center lines is an intricate maze that requires  A LOT of scouting, and choosing the wrong channel, or swimming could kill you and put access at risk for everyone. Please be careful and always have a safety plan, this is serious class 5.



Paddlers have known about Great Falls as long as there has been whitewater kayaking. Many of the features -- such as the Spout, the Fingers, the Fish Ladder -- have names that predate paddling, in some cases by hundreds of years. But it was not until paddlers started running waterfalls regularly in the 1970s that paddlers began to seriously consider running the Falls. The first descent of Great Falls was made in 1975 by local experts Tom McEwan and Wick Walker, with the second descent by Steve McConaughy and Great Falls National Park Ranger Bill Kirby. The Center line was pioneered in the mid- 1980's by Paddlers like Eric Jackson and Chris Good.

River Signals and Helicopters

The Park Service patrols the Potomac with a helicopter most summer weekends. In an effort to minimize confusion, the helicopter pilots are trained to recognize three signals from paddlers.
Everything OK - Tap the top of your helmet with one hand.
Emergency - Wave both arms together over your head (like jumping jacks), holding brightly colored objects if possible.
Need Medical Attention - Form an X with arms or paddles.
Don't signal the helicopters unless you need them! And if being inspected, be sure to give the OK sign if you don't need assistance. Sometimes hikers call in "emergencies" that aren't actually emergencies.

Permit Information

Access to the river is restricted on both the Maryland and Virginia sides. Maryland Side - Paddlers may put in almost anywhere on the Maryland shore, but may not leave the boardwalk across Olmstead Island. To run the Falls from the Maryland side, most people cross the Canal and put in above the aqueduct dam, or put in below the dam at higher levels. Virginia Side - Paddlers may not put in upstream of the Falls. To run the Falls from the Virginia side you must put in at Fisherman's Eddy and then make a difficult ferry and carry above both O-Deck rapid and the Falls themselves. Carry up the Flake for multiple laps. If the rocks are wet, this can be sketchier than running the Falls. Running Great Falls is currently unrestricted. However, to maintain good relations with the National Park Service paddlers voluntarily restrict their runs to less populated times in the park—early morning, late evening, or weekdays—and limit group size and time spent in the rapid. The Park Service is concerned about running the Falls at popular times because it can draw spectators down off the observation decks and closer to the river's edge -- where they might fall in the water and drown. And, if paddlers spend a lot of time running around and relaxing in the Falls, it can give the impression that such activities are not very difficult or dangerous. Since 1975, at least 30 people have drowned in Great Falls, so the Park Service is understandably nervous about this. For more information, see the Guidelines for Running Great Falls as written by the Canoe Cruisers Association in 1999. Today regular Falls runners continue to dialog with the Park Service to make sure access remains open to all.

StreamTeam Status: Not Verified
Last Updated: 2018-12-14 20:04:49


Stream team editor

Rapid Summary

Mile Rapid Name Class Features (Legend)
0.4Grace Under Pressure5.1Hazard Waterfall Photo
0.5The LedgesIV+Hazard Photo
0.5The FingersVHazard Waterfall Photo

Rapid Descriptions

Grace Under Pressure (Class 5.1, Mile 0.4)

Grace Under Pressure

Grace Under Pressure
Photo of Billy Boylan by John Boylan

Arguably the toughest standard line in Great Falls and different as of 2018. Skirt to the right of the top hole, then boof off the right side of the 12' waterfall. The landing is chaotic, so Eddy out right, immediately on the left, or continue down to the Ledges. A swim anywhere in this area is potentially fatal due to what lies downstream. 

The next drop over, Sliding Boad (Class 5.2) crashes into the bottom of Grace and was rarely run due to  horrible sieves on the left. As of 2018 this rapid carries more flow and is temping when Grace is too low

The Ledges (Class IV+, Mile 0.5)

The Ledges

The Ledges
Photo of Eric Jackson by Martin Radigan

A short sequence of 3-5' ledges and slots. They're not that hard, but if you lose control or get disoriented things can go downhill in a hurry. The center- right channel is the traditional double boof line and should be finished by landing right into the swirly pool above the Fingers. The right-most option is called the Angel Slot and is more difficult and committing. To the left, where you DON'T want to go, next to Charlie's Hole (MD side) is an inviting channel called Hollywood Boulevard that funnels toward Twist n' Shout, and the deadly Subway - this should not be run.

The Fingers (Class V, Mile 0.5)

The Fingers

The Fingers
Photo of Gordon Dalton and Harris Haynie by Mike Malone

Also known as the Streamers.  Five slots that can look alike from above, with serious consequences for choosing the wrong one. From river left to right, they are:

Twist and Shout (the Thumb) (Class 5.3) - A narrow, twisty drop with high piton potential. ugly and rarely run, but way better than Subway!.

Subway (6/NR) - A steep double drop with a sieve at the top and a cave at the bottom. This drop has been run accidentally a couple times but has killed two swimmers. Most recently an elite female paddle drowned here in 2013: http://www.americanwhitewater.org/content/Accident/detail/accidentid/3743/  It also  Took the life of an experienced class V kayaker in 2004 who swam into it.  Avoid at all costs. swimming into it is 100% fatal. safer lines are to the right.

The Middle Finger (Class 5.0) - this is the standard line. Pretty straight forward 20' drop but the entrance is only a couple feet from Subway. Calm green water leads into a 4' diameter slot. angle straight.  you slide down  8 feet then lefty boof  about 12' 

The Ring Finger aka Flatliner (Class 5.1) - Shallow landing zone. rocks underneath and to the right. Higher water line. Run out of the eddy just left of center boofing off the nub.  Miss the boof and you’re [censored]. A well known boater ran it too low, broke ribs and ruptured his spleen here. Google: epic fail

The Pinky Finger aka Angel Hair (Class 5.2) - Tricky entrance (angel slot or ferry in). Lands in a boily cauldron between a sheer rock wall and an undercut boulder. If you swim in the pocket, there's a small underwater ledge against the Flake that you can stand on while awaing a rope and figuring out your next move.

Make SURE you know which slot to take. there are no arrows painted on the rocks and the wrong choice at the wrong level could be fatal.

User Comments

Users can submit comments.
September 2 2018 (136 days ago)
Geoff CalhounDetails
The Center Lines has changed in the Spring of 2018. the ideal flows are now different, its not
being run low as was previously possible. There is less water in Grace Under Pressure, and while
the drop is the same, the entrance and landing are different.
July 12 2013 (2014 days ago)
baldoam (151663)
Here is a functional link to a story about the kayaker who swam into Subway in 2004
http://www.washingtonpost.com/wp-dyn/articles/A62644-2004Oct25.html (link on the main page is
October 27 2008 (3733 days ago)
Scott AndersonDetails
Thanks for your input. As the streamkeeper, I have to use my best judgment when listing river data.
The solutions aren't always ideal, but I will try to explain my rationale with regard to gradient.
"Please explain how a 1 mile stretch of river can have average gradient of 100 fpm and maximum
gradient of 500 fpm." The river drops 100 feet between the put-in and the take-out, which are 1
mile apart. So the average gradient is 100 fpm. However, the heart of the run drops 50 feet in 0.1
miles, for a maximum gradient of 500 fpm. "Maximum gradient figures cited 'up top' should always be
computed across a full mile, otherwise they are meaningless." Says who? There is no standard way to
calculate gradient. Leland Davis calculates gradient mile by mile in NC Rivers & Creeks, but
Stafford and McCutcheon use terms like "200 fpm," "200 fpm action," and "200 fpm crux" in The New
Testament. Which is right? Great Falls is a park and huck, so calculating gradient mile by mile
would be meaningless. Nobody puts in above Great Falls unless they plan on running it. They're not
there for the paddle in and the paddle out. The only section that counts is Great Falls itself,
which is 500 fpm. I would put "500 fpm crux" if I could, but the AW page builder doesn't give me
that option. Furthermore, removing the 500 fpm maximum gradient from 'up top' could mislead people
into thinking Great Falls is no steeper than the Upper Yough. "If you wish to convey that some
shorter portion has steeper gradient, you may express that within the text of the description..."
The description includes the following statement: "The main Falls lines drop fifty feet in
one-tenth of a mile." The reason I include the maximum gradient up top is that nobody reads the
September 2 2008 (3788 days ago)
x (1)
I was out here the other day to run the Spout. The temperature was supposedly about 93 degrees,
but, even though I arrived on Flake Island after sunset, the heat was very, very oppressive.
Sitting down to rest did not help, as the rocks were super-heated by the sun to around 120 degrees.
I was rapidly becoming seriously dehydrated and probably lost about 30 percent of my strength
before putting in to run the rapid. This rapid should probably not be scouted during daylight in
the summer. So watch out for the summer heat; I came close to having a heat stroke!!! Also, the
water temperature is close to 100 degrees, too, so it provides close to zero cooling.

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