Bloede Dam
Bloede Dam was a hydroelectric dam on the Patapsco River about a mile upstream from Orange Grove in Patapsco Valley State Park. Built in 1907, it is believed to have been the world's first submerged electric-generating plant, with its machinery housed inside the dam. It stopped generating around 1930 and was removed in 2018 to reopen the river to migratory fish. You can visit the site on foot or by bike along the River Road past Orange Grove Shelter #106, or from the Grist Mill Trail across the river.
Bloede Dam at a Glance
How to Get There
Enter the Avalon Area at 5120 South Street, Halethorpe, and drive the park road to Orange Grove (see Swinging Bridge for parking). From there:
- River Road: continue upriver on foot or by bicycle beyond Orange Grove Shelter #106.
- Grist Mill Trail: cross the Swinging Bridge and follow the Grist Mill Trail upstream on the other bank.
DNR's Avalon fishing rules still close the water within 300 feet above and below the dam, and the same 300-foot rule applies at every dam on the Patapsco. Check posted signs.
The Experiment
Local businessman Victor G. Bloede and electrical engineer Otto Wonder built the dam as an experiment. A taller dam would have flooded communities upstream, so the designers put the generating machinery inside the structure itself. DNR's history hike describes a reinforced-concrete dam 220 feet across and 40 feet tall, with a 168-foot spillway and 19 internal buttresses. Engineers around the world studied it.
Its prototype equipment soon went out of date, and the plant shut down after a couple of decades. DNR's pages differ on the dates: the main park page says it ran from 1907 until about 1930 and was removed in 2018, while the self-guided Grist Mill hike says it was built in 1906, shut in 1924 and removed in 2019.
Why It Came Out
The Patapsco's dams blocked fish from moving upriver to spawn. DNR's history guide notes that nearly all of the river's dams have now been removed, and shad and herring can spawn upstream for the first time in 150 years. Bloede's removal was part of that work. Union Dam near Hollofield came out in 2010 (Hollofield Area), while Daniels Dam upstream still stands, with a fish ladder (Daniels Area).
Bloede Dam FAQ
Is Bloede Dam still there?
No. DNR says the dam was removed in 2018 to restore passage for migratory fish. You can still visit the site.
Where was Bloede Dam?
On the Patapsco River about a mile upstream from Orange Grove, in the Avalon Area of Patapsco Valley State Park.
How do I get to the Bloede Dam site?
Park at Orange Grove, then walk or bike up the River Road past Shelter #106, or cross the Swinging Bridge and follow the Grist Mill Trail upstream.
Why was Bloede Dam famous?
It is believed to have been the world's first submerged hydroelectric plant, with its generating machinery built inside the dam.