Potomac - 4. Mather Gorge to Lock 10


Potomac, Maryland, US

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4. Mather Gorge to Lock 10 (Mather Gorge)

Usual Difficulty I-IV (for normal flows)
Length 6.5 Miles
Avg. Gradient 8 fpm

2004: The Year Of Rocky


2004: The Year Of Rocky
Photo of Peter Bross by Lauren Rarick @ 4 ft.

Gauge Information

Name Range Difficulty Updated Level
POTOMAC RIVER NEAR WASH, DC LITTLE FALLS PUMP STA
usgs-01646500 2.20 - 7.00 ft I-IV 01h57m 3.65 ft (running)


River Description

The Potomac River below Great Falls is literally in the back yard of Washington, D.C. This fact contributes to the strong boating community in the metropolitan region. Mather Gorge, where this section begins, is a stunning cliff-lined gorge. Further down, the river maintains it's wild and remote feeling, except for at choice spots where Virginia has allowed sloppy development to mar the shore.

The river offers play and practice for beginners to experts and numerous sections can be run. This description will deal with the rapids and access points and doesn't provide details on the numerous play spots.

It should be noted that the stretch of river from O-Deck just below Great Falls thru Wet Bottom offers some of the best big water paddling in Maryland. 10,000 cfs thru a 100 foot wide gorge makes for some large waves, surging eddies and boiling eddylines. Below Mather gorge the rapids get considerably easier. Here is one playspot guide: Potomac Playspot Project. And another: Potomac Paddlers. Another popular playspot guide developed by David Mackintosh is currently offline. It will be linked here if it is revived.

Access Points:
Great Falls is located to the west of Washington DC. Best access is off of I-495 to Clara Barton parkway/Carderock exit on the Maryland side. Take the parkway west about two miles to McArthur Blvd. Continue west on McArthur about another mile to the Anglers Inn parking area. To access the Virginia side, exit I-495 to Old Georgetown Pike/Hwy 193. Go west about 4 miles to Old Dominion Drive and take a right into the park.

Maryland:
- Sandy Beach. Park at Great Falls National Park (fee area), reached via MacAuthur Blvd. in Montgomery County, MD. Carry 1/4 mile south along the C & O Canal towpath; take trail on the right that leads to Sandy Beach putin.

- Angler's Inn. Reach via MacAuthur Blvd. Park in one of three gravel or dirt lots across from the Angler's Inn, a fine restaurant. Carry across the canal, then 100 feet south on the towpath, then right down to the shore. From the river, the beach is easily seen on river left.

- Carderock. Reach via Clara Barton Parkway. Park at Carderock picnic area. Path across grassy area leads to small access. From the river, the access is a muddy bank.

- Lock 10. Reach via Clara Barton Parkway. Park at Lock 10 lot. Trail leads down to shore. From the river, you need to take a river left side channel to find the path.

Virginia:
- Fisherman's Eddy. Park at Great Falls National Park (Virginia - fee area). From lower lot, carry across picnic area to steep trail that leads to Fisherman's Eddy.

- Rocky Island. From Great Falls, Virginia, walk south on trail from picnic area to a small footbridge and walk left down the rocky gully access Rocky Island surfing waves.

Rapids (in order from the base of Great Falls to Lock 10).
-- O-Deck (Class III). Primarily a playspot with large surfing waves. Adjacent to Fisherman's Eddy. Using this for a downriver trip is inconvenient because shuttle must be set on Virginia side of river.

-- Fishladder (Class II+-III). Formed by current from fishladder around Great Falls. Fast current, big waves and a messy pourover at some levels.

-- S-Turn (Class II-IV). Converging currents and constricted river form dynamic waves, current and whirlpools. Rocks form pourover holes at lower levels.

-- Rocky Island (Class II-III). At 4-5 feet on LF gauge a fine series of surfing waves exist. Lower levels present Class II waves.

-- Wet Bottom Chute (Class II). At normal levels is a 3 foot sloping ledge drop that can be run most anywhere.

-- Difficult Run Rapids, Maryland, Center and Virginia Chutes (Class II). Washington's practice spot and home to the Maryland chute playspot. Each chute offers a different type of practice. All lines are straightforward.

-- Offut Island (Class II). Series of tight breaking waves on river left below Angler's Inn putin. Best at more than 4 feet.

-- Yellow Falls (Class II+). Two step drop through breaks in river wide ledge. Can be scouted from river right ledge. At low levels a tricky rock is exposed near the bottom of the traditional line.

-- Stubblefield Falls (Class III). Large and long series of standing waves just above I-495. The last whitewater before Lock 10.


Playspot List & Levels:
2.5' - 4.2' Wet Bottom (Class 3)
2.6' - 2.8' Horseshoe (Snodgrass) Wave (Class 3+)
2.7' - 2.9' Fishladder Wave
2.7' - 2.9' Portage Waves (Class 2)
2.7' - 3.0' Annie's
2.7' - 3.0' O-Deck 3 (Class 3)
2.7' - 4.0' Maryland Chute (Class 2+)
2.7' - 4.2' Virginia Chute Wave (Class 2)
2.8' - 3.3' Bloody Good
3.3' - 3.6' O-Deck 2 (Class 3)
3.6' - 3.8' O-Deck 1 (Class 3)
3.6' - 3.7' S-Turn (Class 3)
3.7' - 3.9' S-Turn
3.7' - 4.1' Showcase (Class 3)
3.9' - 4.1' Simon Says
3.9' - 4.8' Rocky Island Waves (Class 3)
4.1' - 5.4' Center Chute Ledge (Main Hole) (Class 3+)
4.2' - 4.7' Upper Center Chute Ledge (Class 3)
4.2' - 4.4' Fish Counter
4.2' - 5.4' Offut Waves (Class 2)
4.5' - 6.0' Tight Quarters
4.8' - 5.2' Gil's Hole (Lower) (Class 3)
4.9' - 5.4' Gil's Hole (Upper) (Class 4)
5.3' - 6.4' Rodeo Zone
5.4' - 6.5' Center Chute Wave (Class 3)
6.0' - 6.7' Rocha Motel
6.0' - 7.6' Skull Island Wave (Class 2+)
6.2' - 6.6' Dave's Wave (Class 3+)
6.4' - 8.0' Showcase
6.7' - 6.9' Super Dave
6.7' - 7.0' Shoulder Snapper (Sweetie-pie) Wave
6.8' - 7.5' Corner Hole (Fudgepacker) (Class 4)
7.0' - ?.?' Sweetie-pie Wave
7.2' - 8.2' Last Supper
7.3' - 8.0' Elbow Wave
7.3' - 8.8' Dead Cow Hole (Class 3+)
7.9' - 8.8' Bud (also called Butt) Hole
8.0' - 9.5' Pencil Sharpener
8.0' - ?.?' Zambezi Wave
8.5' - 9.5' Eraser
9.0' - 9.5' Round the Corner

From Potomac Paddlers website, added May 2004

National Park Service Great Falls Page

NPS Great Falls Map

These guide books provide good references for this section: Sehlinger, Bob, et. al.; Appalachian Whitewater, the Southern States. Gertler, Ed; Maryland and Delaware Canoe Trails.
StreamTeam Status: Verified
Last Updated: 2004-06-07 23:28:34

Rapid Summary

Mile Rapid Name Class Features (Legend)
0.0O-DeckIIIPlayspot Photo
0.3FishladderIII
0.3S-TurnIII+
0.3Sandy BeachPutin
0.4Rocky IslandIII
0.6Wet BottomII+
1.9Difficult Run RapidsII+Playspot
2.3Anglers Inn AccessAccess
3.0Offut IslandII+Playspot
3.8Yellow FallsII
4.3Stubblefield FallsII+
5.5Carderock park access
6.5Lock 10Takeout

Rapid Descriptions

O-Deck (Class III)

Lone Surfer at O-Deck In Mather Gorge

Lone Surfer at O-Deck In Mather Gorge
Photo of Unknown Boater by Emmy Truckenmiller @ 4 ft.

Easiest access is from the VA side as a park & surf. Enter Great Falls park and take an immediate right into the first parking area. Just above the lower observation deck is the trail down to Fishermans eddy. Carefully work down the steep trail to the waters edge. Ferry across and slightly upstream to access the O-deck wave.

From the MD side you will have to work upstream past the mouth of the fishladder and attain up about another 300 yards to access O-deck.

Fishladder (Class III, Mile 0.3)
Wierd currents where the fishladder dumps into the main stem of the Potomac.

Sandy Beach
Access point river left just below the fishladder. The trail is just off the towpath down from Lock 17, upstream of the overlook. Can also be accessed from Anglers by paddling up the canal a mile, then carrying another 0.4 mile to the put-in.

Rocky Island (Class III, Mile 0.4)
Large bigwater waves and eddy lines at higher flows. Good long boat surfing between 4 and 5 feet on the gauge.

Difficult Run Rapids (Class II+, Mile 1.9)
Maryland, Center, & Virginia Chutes.

Anglers Inn Access
Access point river left

Offut Island (Class II+, Mile 3.0)
Good surfing on the river left side of the island from 4.2 to 5.0 on the gauge

Stubblefield Falls (Class II+, Mile 4.3)
Last rapid above the I-495 bridge.

Lock 10
Access point river left


User Comments

Users can submit comments.
May 11 2004 (4427 days ago)
Brad RobertsDetails
Subject: Record high run on Potomac above DC - Sunday 1/21/96
This is the only article in this thread
View: Original Format
Newsgroups: rec.boats.paddle
Date: 1996/01/22


TRIP REPORT: date - 1/21/96; level - 19.31' at Little Falls gauge; put-in:
Bear Island 200 yards above jumping cliffs in Mather Gorge; take-out -
Lock 10 on C&O Canal; difficulty - if you believe in runnable class 6,
this was it, baby!!

Sunday saw the highest known run ever down the Potomac Gorge, surpassing
the 1985 run at 18.3' by Davey (the resistor) Hearn et al. We put in at
about 1:15 pm, just as the river crested. The Little Falls gauge was
confirmed at 19.31' at 1:00 pm. We estimate the cfs at 375,000, which is
extrapolated from data supplied by the Army Corps of Engineers for 1985
flood. I tried to get confirmation from the Corps for yesterday's cfs, but
without success so far.

The water was indescribably monstrous and chaotic. I led out of the put-in
eddy, and as I was crossing the boil zone towards the shear line, I was
attacked by a massive moving hydraulic about 8' high. It pulled me
completely underwater for 3 or 4 seconds before dissipating and letting me
go. We all realized very quickly that a blown skirt might be fatal.

The main action was at the rapid named Jumps, which started about 200
yards down from the put-in and continued for 1/2 mile. This rapid occurs
in a spot which is normally placid flatwater. I believe it was named by
the 1985 crew, who were the first to discover it. It is named after an
area popular for it's 50' cliff jumps down into the river. The tops of
these cliffs were probably 15-20 feet underwater yesterday.

Jumps is formed from an interesting hydrological phenomenon wherein Mather
Gorge fills in to the brim (about 60' above the height of the average flow
of 7,000 cfs) and virtually dams up Great Falls, which is about 1.5 miles
upstream of this point at the top of Mather Gorge. As a result, Great
Falls flattens out to some extent, and the drop which normally occurs at
Great Falls (about 60 vertical feet) is delayed as the incredible
funneling pressure of the relatively narrow, sheer-walled Mather Gorge
keeps the river elevated. Only when the vertical walls give way to a
less-steep, rocky valley does the river get to madly eject itself from
this bottleneck.

This sight, the Jumps, is one of the most awesome spectacles of nature
I've ever beheld. Hundred of thousands of cfs tumble wildly out of the
gorge through giant boils and folds in a state of mad chaos. Riding
through this involved going from one envelopment to another. The wave tops
periodically broke into temporary, truck-sized hydraulics. But each of us
only got nailed by two or three of these during the worst part of their
cycles. There was some debris and a few trees, but it was not an
overriding concern, and no one was hit by any debris.

At low water there is a 45' high mound of rocks on the center left here,
sort of a high-water island. Yesterday this rock was well under water and
formed a massive 25' high continuous hydraulic (it was here that Kirk's
boat was smashed back in '85). This hole was maybe 50 yards wide, and
extended 50 more yards into a wave on either side. It was easy to miss
this beast, but it was somewhat unsettling to go by it on the shoulder of
the wave extension.

Below Jumps, the river normally makes a 90 degree left turn below Madeira
School towards Angler's Inn put-in, then turns back to the right.
Yesterday the river cut this corner, with less than 40% of the water going
down the existing river channel. There were two major channels, one to the
right of Skull Island, and another of similar size to the right of it
(into the area of Black Pond). The rapids in here, which we were not
expecting, were nearly as intense as Jumps, but much shorter. I hit just
two massive waves, one of which broke on me.

Of the four in our group, two emerged from all of this unscathed (myself
included), one swam and was pulled out by us, and the fourth disappeared.
Later, after a lot of worrying and some soul searching, we found him safe
at home. He had apparently engaged some trees at the bottom of the Black
Pond channel, lost his gear, and swam to shore. He hiked up the Difficult
Run Creek drainage to the nearest house, and the homeowner drove him back
across the river to his home in Cabin John, MD.

This trip was of course the experience of a lifetime. While we all agreed
that we would probably not do this again, it was exhilirating beyond
belief. Perhaps one or two in our party should not have gone or perhaps we
all made sound decisions. We certainly knew the risks and we knew some
elements were not in our control (a branch poking through your spray
skirt, or a tree in the hole with you). We had some 50 years of paddling
experience between the 4 of us, mostly in these waters. Our weakest member
had 5 years experience. No one was pressured to put in.

We planned the trip carefully to avoid contact with authorities using
alternate parking and access points and other measures. We luckily did not
see authorities (other than helicopters) en route to the put-in, nor did
we see any signs indicating that the river was closed. It was, apparently,
but we did not know this. We understood that Park Police or Rangers would
have no choice but to turn us back (what are they going to say, "oh, yeah
anything under 400,000 cfs is perfectly safe, go right ahead"), so we
avoided contact.

The whole question of river "closure" has already provoked some debate on
this newsgroup in connection with Davey (the resistor) Hearn's arrest and
TV interview on Channel 9 last night. And it will probably continue to get
a lot of attention. We are grateful that we did not get tripped up by this
problem and were able to make the decision to go or not go purely based on
our scouting. We did talk to several fireman, county police, park police,
and rangers at the Lock 10 take-out, but they were quite civil with us and
did not accuse us of being insane. They just said get out and we did, as
our run was over - thankfully!

Paul Schelp
1/22/96
May 11 2004 (4427 days ago)
Brad RobertsDetails
For the out of towners:
Park at Anglers Inn. 3 major options.
1. walk down the trail, across the bridge, and veer to the left to the wide trail down to the
river. From there you can attain up to the maryland and center chute. Easy attainment even in a 6
foot long boat. Best to just follow the crowd. Someone is always there. Float back down to anglers
when done. Center is best around 6 feet. Huge wave, nice eddy. Turns into a hole in the 5 foot
range.

2. using the same put-in, float downstream and go to the left of the big island. These are the
offut waves. Lots of fun in the 4 foot range, and much more user friendly for novices than the
upstream chutes. To get back to your car, get out on river left. Follow the trail DOWNSTREAM, it
will eventually take you back up the hill to the C&O towpath. From there either paddle back up
the canal or carry your boat a half mile back to anglers.

3. From anglers, walk down to the canal, hop in your boat and slide into the canal. Paddle upstream
about a mile. Get out when you get to the lock and carry your boat up the trail past the overlook.
From the overlook you will look down on the sandy beach put-in. Keep going up the trail until you
see the main wide trail on the left going down to sandy beach. From there, pick one of the many
options and eventually float back down to anglers. It seems that most people access the Rocky
Island waves this way. Good surfing up by sandy beach above 6 feet. Major boiling eddies and swirly
water. Rocky Island is a great surf in a fast long boat around 4.5 feet.

Enjoy.
Brad.


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