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 00h58m 61.8 cfs (too low)

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

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