Daniels Dam on the Patapsco River heading for removal: ‘The last piece of this puzzle’

With an influx of federal funding, engineers will begin studying and preparing for the removal of the Daniels Dam in Howard County — one of the last remaining blockages on the Patapsco River.

In May, the National Oceanic and Atmospheric Administration designated $1.8 million in federal funding for the planning and permitting process to begin. The funding will go to American Rivers, a nonprofit that focuses on restoring river health, including by removing dams.

It’s the final leg of the nonprofit’s 15-year push to restore a free-flowing Patapsco, which began with the removals of the Union and Simkins dams in 2009 and 2010, and continued with the Bloede Dam’s demolition in 2018 .

The only other dam remaining on the main stem of the Patapsco River is the Liberty Dam, which sits at the base of the Liberty Reservoir, a key source of drinking water for the region. So the Liberty Dam is not currently a candidate for removal, said Jessie Thomas-Blate, a director of river restoration with American Rivers.

The dam removals promise ecosystem benefits by returning rivers to their natural states, including by reopening upriver habitats to migratory fish like American eels, river herring and shad.

“The vision, I think, for this project from the beginning was there’s suite of four dams on the Patapsco … We would like to try to see if we can restore this whole stretch, for the benefit of people as well as nature,” Thomas-Blate said.

But the removals also pose inherent risks that must be carefully managed, since they unleash the sediment formerly trapped behind dams. The Daniels Dam is upstream of flood-prone Ellicott City, which sits along a tributary that meets the Patapsco.

“At that juncture, we don’t want to have sediment gathering and causing any backing up of water into the city,” Thomas-Blate said.

As part of the forthcoming studies, engineers will evaluate the type and amount of sediment trapped behind the Daniels, and try to predict its behavior after the dam removal. Possible actions, like dredging sediment from behind the dam, or installing stabilizing structures, will be considered as well, Thomas-Blate said.

Engineers also will compare removing the dam with the alternative — keeping it in place and continuing to maintain its aging infrastructure, even though its primary purpose has long since passed. The dam was originally constructed in the 1800s to power canvas and denim mills along that section of the Patapsco, but no longer does so.

The dam’s owner, the Maryland Department of Natural Resources, supports the removal effort, said agency spokesman Joe Zimmermann in a statement. After the studies are completed, DNR will make the final call about the dam’s demolition.

“Department staff will now conduct internal planning among our involved units on next steps and will eventually conduct public engagement as well,” Zimmermann wrote.

The dam is a popular attraction inside Patapsco Valley State Park, attracting picnicking families, anglers, swimmers and kayakers. The impoundment has created an area conducive to paddling, Thomas-Blate said, and officials want to engage those users during the discussions about the site.

Demolishing the dam also could remove a potential safety risk — one that sometimes necessitates water rescues. Swimming within 300 feet of the dam is prohibited because of potentially powerful currents. And despite signs warning against it, some swimmers climb the dam and jump into the river below.

There is no specific timeline for the dam’s potential demolition just yet, Thomas-Blate said. But the grant with NOAA lasts three years, and American Rivers aims to complete the design work and permitting in that time, if not the entire project.

After that, additional funding would be needed to actually demolish the structure, Thomas-Blate said. For the previous dam removals, funding has come from a variety of sources, including federal, state and private funds, Thomas-Blate said.

The methodology isn’t set yet, either. The demolition of the Bloede Dam used explosives, but other demolitions have required only an excavator, tearing apart the structure piece by piece, Thomas-Blate said.

Following the removals of the other dams on the Patapsco, observers have noticed positive changes — sometimes more positive than expected. After Bloede was demolished, a ladder on the Daniels Dam for American eels saw a dramatic uptick in usage , indicating the creatures were successfully making their way upstream in far greater numbers without the dam in place downstream.

Those numbers have held steady, though the homemade ladder installed by park personnel is beginning to show signs of wear, Thomas-Blate said. The hope is that demolishing the Daniels Dam will further increase the presence of eels and other key fish species.

For the eels, the removal will reconnect more than 183 miles of habitat, according to American Rivers, and 65 miles for river herring and shad.

“[It’s] sort of the last piece of this puzzle,” Thomas-Blate said.