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Seneca Creek - Black Rock Mill to Riley's Lock Boat Ramp

Seneca Creek, Maryland, US


Black Rock Mill to Riley's Lock Boat Ramp (Lower Seneca Creek)

Usual Difficulty I-II (for normal flows)
Length 7.25 Miles

Gauge Information

Name Range Difficulty Updated Level
usgs-01645000 100 - 400 cfs I-II 00h40m 588 cfs (too high)

River Description

The entire course of Seneca Creek stretches many, many miles from the headwaters of Great Seneca Creek in Damascus Maryland through the cities of Gaithersburg, and Germantown and on down through Darnestown and Seneca, Maryland to the Potomac River. While not the action-packed whitewater trip that most users of this site are used to, it does offer a nice float trip for beginners with a few navigation and stability challenges thrown in for fun. The creek itself is maintained by a very few volunteers who work in conjunction with the MD park service to remove strainers, but often has large amounts of wood in certain less-maintained stretches which can present a complete set of challenges all their own. On the author's first descent of this reach, portaging around jams and river-wide strainers was necessary 6 times in a 4 mile section due to vast quantities of wood left over from the previous summer's DeRecho storm . However, the park and its volunteers have since cleared these log jams and strainers once notified of them (late 2013). 

The water quality of this section is generally good. Sediments and pollutants picked up in the more populated areas have, for the most part, dropped out of the water by the time they reach the old Black Rock Mill and the bottom of the creek is clearly visible through most of the trip with the exception of some deep and long pools behind two low dams on the trip. 

Access is reasonably good as is the ability for rescuers to reach those in trouble thanks to the Seneca Greenway Trail runnign parallel to the creek for most of its length as well as several access points from local roads which can bring vehicles close to the creek for either rescue or simply cutting the trip into more manageable chunks. 

The section below River road is mostly slackwater which flows very slowly to the Potomac past Riley's Lock and the Seneca Creek Aqueduct. You have the option to take out at Berryville Road, but parking is limited and tight. You also miss the chance to see the beautiful Aqueduct at the take-out if you choose to end the trip at Berryville Road. 



StreamTeam Status: Not Verified
Last Updated: 2013-11-18 18:46:40


Rapid Summary

Mile Rapid Name Class Features (Legend)
0.0Black Rock Mill Put-InN/APutin Photo
1.5Darnestown Road DamIIPhoto
5.8Tschiffely Mill DamIIPhoto
6.0Berryville Road AccessN/AAccess
7.3Riley's Lock Take-OutN/ATakeout Photo

Rapid Descriptions

Black Rock Mill Put-In (Class N/A)

Black Rock Put-In

Black Rock Put-In
Photo taken 06/01/13 @ 100 cfs

Put in at the old Black Rock Mill on Black Rock Road.

Darnestown Road Dam (Class II, Mile 1.5)

Darnestown Bridge and Dam

Darnestown Bridge and Dam
Photo taken 06/01/13 @ 100 cfs

Low head dam that stands just a few feet high underneath the Route 28 bridge. Either flood control or possibly covering a water or sewer line that runs along the road. Best approached from river left and taken head on. Expect some scraping at lower levels and a smoother ride at higher levels.

Tschiffely Mill Dam (Class II, Mile 5.8)

Tschiffely Mill Dam Bottom

Tschiffely Mill Dam Bottom
Photo taken 06/01/13 @ 100 cfs

The tumbledown ruins of a stone and mortar dam built to divert flow from the creek, across the peninsula, and into the mill at Seneca Ford (present day River Road). Expect it after crossing the first long, deep pool on the creek when you can see a distinct horizon line. You will not hear the rapid until you are almost on it. Easily scouted from river right, you'll want to check it out from the shore as it is a quick drop over lots of rocks. The locals often build a sluice out of the loose rocks in the summer for tubing. 

Berryville Road Access (Class N/A, Mile 6.0)

Quick access to the stream, and  a good place to check the water level before committing to the trip. Park along the side of the road and walk the trail upstream to the ruins of the Tschiffely Mill dam. If there is enough water for you to make a scraping descent of the dam, you'll have enough water for the whole trip. 

Riley's Lock Take-Out (Class N/A, Mile 7.3)

Boat Ramp at Takeout

Boat Ramp at Takeout
Photo taken 11/18/13

Public boat ramp with access to the Potomac River

User Comments

Users can submit comments.
October 22 2018 (90 days ago)
Mike MartinDetails
Hi all, here's the latest strainer report that I got from a Seneca Creek State Park staffer on
10/22/18: "The last report on Seneca Creek that I got was that the last big rainstorm all but
cleared out Black Rock to Berryville, but that Riffle Ford to Black Rock (Which I agree with you is
the better section) has become fairly jammed up. Fortunately, we are making plans to do a day of
strainer removal some time soon, since a logjam above Riffle Ford has blocked off enough water to
threaten to erode the bank enough to threaten one of our trails." It's great to see that a few park
staffers have taken to paddling the creek on their off hours, and it was a pleasure to meet and
paddle with them when CCA put together a trip for them last summer.
September 12 2018 (130 days ago)
Mike MartinDetails
I've run Seneca Creek twice this summer with several Canoe Cruiser's Assn, leaders and SCSP staff
to assess the strainer situation report the following as of late August. The Creek is mostly open
with a few easy drag arounds/ drag overs, and a few duck unders/tight squeezes, but beware of the
following: A massive, newly downed scycamore slipped off the bank earlier this year, and it's
river-right root ball may collect wood. The tree blocks enough of the creek that the river-right
banks got carved out during the last high water event so that logs clogging its channel got washed
out as of late August. If more collect there (about two miles below Rt. 28), the best portage is on
river-left, with fairly easy egress and reentry. Below there, about a mile above the Berryville Rd.
access point, a new, river-wide strainer presents a more serious challenge, given the steep banks
and its propensity to pile up any wood that floats into it. At the 80 or so CFS we had, we were
able to hump and over some of the wood, then swim our boats through the rest of the pile. No
problems below. With more high water coming from Hurricane Florence, the situation will likely
change in mid Sept. I'll try to post an update an photos later this month. Meanwhile see the CCA
Facebook page for phots from our last trip.
April 26 2018 (269 days ago)
Mike MartinDetails
April 2018 - 4 strainers reported on Seneca Creek below Rt. 28 From a report sent by Tim Tilson of
the Canoe Cruisers Assn. "The two impassibles are about at the one and two mile mark. I doubt any
chain saw crew will be able to fix these. The first one required the boats to be hauled over
blockage. You had to get out, onto the strainer and haul them over Ed Evangelidi style because the
banks were just too high. The second required a portage of around 100 ft. Easy to do river left.
The third required strainer was passable but only with very good boat control. You enter river left
into a 3' wide slot with a limb on both side and an over hanging branch. Canoes had to point, drop
to the deck and pass through. Not that hard but boat control required. And we had a kayakers there
as the "grabber". Probably beyond the ability of a family in an open boat. The fourth, Alf cut some
brush back and is fine now. My worry would be on higher water." I've passed this report along to
Seneca Creek State Park - hopefully their volunteers can deal with the big ones and keep the water
trail open and safe for relative novices to run.
July 13 2014 (1652 days ago)
axesspaddler (156723)
Ran the Seneca from Route 28 to Rileys Lock at 130 cfs on July 13, 2014. Absolutely beautiful
seemingly remote creek yet very close to civilization. Low water but passable. THANKS to Mike for a
very accurate trip report in June. I used the passageway you cut (literally one-kayak wide) which
would have been challenging at any higher level. Now another tree is down (probably in the last day
or two) but passable. Creek splits at approx. mile 4-5. Right channel is completely blocked by the
broken-off top of a large tree upside down in the water - a BAD strainer. Easily portaged but at
higher levels you will be nearly on top of it before you can exit. The other channels may be clear
(I didn't backtrack to run them). So do not choose the right-hand channel at the split. NOTE:
Several other branchy trees are down at various points along the route near to shore and parallel
to the current BUT at some spots the natural current flow wants to push your boat into them =
easily manageable but potentially dangerous for beginners or anyone not paying attention because of
the consequences of getting sucked in. Stay alert but enjoy this beautiful stretch of "remoteness"!
I was the only one there on a hot summer Sunday in July...!
June 2 2014 (1693 days ago)
Mike MartinDetails
The trip report below reports only one strainer between Rt. 28 and Riley's lock. Mike, Here's the
TR. For me pretty much a PFD. Very impressed at its beauty & isolation. The hole we made in the
single downed tree blocking the creek - is passable only by kayak - it took us 20 minutes to saw
our way through. - Alf SENECA CREEK 300 cfs 5 boats Miki leads - Sat, 1 June 2014 For our part, I
came along with Miki and Barb and a couple Doug and Lisa on the Seneca Creek - which I hadn't been
on since a Jim Finucane clean-up in 2001. Our cfs was 300 - only one strainer, which we sawed our
way through. In at 4:10 - out at Rileys Lock at 6:30. Fine level, scarcely ever touched bottom. I
was most impressed that such a pretty creek is open and available; my notes from 2001 say that
there were about 8 places needing cutting out. In fact, I'm thinking of getting out the tin canoe
and taking Rita down! Sunny, cool.
May 28 2014 (1698 days ago)
Mike MartinDetails
I paddled Seneca Creek several times this spring and found it clear of strainers, between MD Rt. 28
and Riley's Lock, but rather strainer-choked between Black Rock Rd. and 28. However, the most
recent trip on Seneca Was on May 11 -- a few days before we got the 3" rain dump on May 14-15.
George, can you clarify what the strainer situation is now between 28 and the takeouts at
Berryville Rd. and at Riley's? I now live about 4 miles from the Rt. 28 put in and will try to keep
an eye on the creek, will post more when I get a chance to run or scout it.
May 25 2014 (1701 days ago)
basslergeorge (156541)
we paddled this reach on 5/23/14 lots of strainers/Trees block passage. from the black rock mill to
rileys landing we had to portage around at least 20 riverwide strianers. most are very big trees
that will take a lot of work to remove. river was low enough about 3.5 ft , that the strianers
presented no big safety hazard but higher water trips would not be advised.