BALTIMORE -- An emergency passageway —264 feet wide and 11 feet deep— was cleared on Monday to allow essential vessels to pass along the Patapsco River around the mangled wreckage at the Key Bridge disaster site. 

A second 15-foot channel is expected to open soon to allow marine vessels access to the Port of Baltimore, along with a third, even deeper channel. 

The Tugboat Crystal Coast, pushing a fuel barge, was the first vessel to transit the newly created temporary alternate channel in Baltimore following the bridge collapse, according to the U.S. Coast Guard.  

"Today was an important milestone in the process of beginning to pull the wreckage out, beginning to open channels. We know we still have work to do," Governor Wes Moore said on Monday.

U.S. Coast Guard Captain David O'Connell, the federal on-scene coordinator for the Unified Response to the bridge collapse, said in an exclusive interview with CBS News that auxiliary channels are planned to open along the northeast section of the channel and one running along the south. 

There's pre-existing debris along the south side of the channel that the Coast Guard is working to remove. 

"We're working with salvage to pull that out of the water tomorrow," O'Connell said.  

The two temporary channels will mainly be for response vessels, commercially essential vehicles and those participating in salvage efforts.

A deeper third channel is in the works that would require up to 25 feet of depth to operate, but more debris surrounding the striking ship, the Dali, needs to be removed. 

"I anticipate smaller draft commercial vessels, maybe some small tugs in the next few days," O'Connell said. "That's that 13 to 14 foot draft, but that unfortunately, that's not a lot of vessels. But it certainly is a start on our way to phase three, which will hopefully get us to 20 to 25 foot draft and that would be a lot more commercial vessels."

Debris removal continues

The Unified Response team is continuing the difficult job of cutting away pieces of what remains of the Key Bridge, which collapsed when it was struck by a cargo ship last week.

A 350-ton chunk of steel was expected to be removed Monday evening, but lightning was a concern. 

"What we're finding is it is more complicated than we hoped for initially," said U.S. Coast Guard Rear Admiral Shannon Gilreath, describing the challenges. 

A 200-ton piece of the bridge was removed from the crash site Saturday. 

"This will mark an important first step along the road to reopening the Port of Baltimore," O'Connell said. "By opening this alternate route, we will support the flow of marine traffic into Baltimore."

This action is part of a phased approach to opening the main channel, according to Baltimore Mayor Brandon Scott's office.

The channel will be marked with government-lighted aids to navigation and will have a controlling depth of 11 feet, a 264-foot horizontal clearance, and a vertical clearance of 96 feet.

The current 2,000-yard safety zone around the Francis Scott Key Bridge remains in effect and is intended to protect personnel, vessels, and the marine environment. No vessel or person will be permitted to enter the safety zone without obtaining permission from the COTP or a designated representative, the mayor's office said.

A survey is also underway to determine how hard the ground is around the Dali to help come up with a strategy for removal.

The Unified Command is comprised of the U.S. Coast Guard, U.S. Army Corps of Engineers, Maryland Department of the Environment, Maryland Transportation Authority, Maryland State Police, and business consultant Witt O'Brien's, which is representing Synergy Marine, the Singapore company that managed the striking ship.

The governor's office tells WJZ the cleanup effort at the wreckage site of the Key Bridge will be a "round-the-clock" effort until the Port of Baltimore is back open.

Gov. Wes Moore also said the effort "is going to be a long road.

"It's a very complex operation, but movement is happening," Moore said on "CNN Sunday Morning." 

Moore said the priorities are recovering the four remaining victims, clearing the channel to open vessel traffic for the port, and providing support to those who have been impacted by the crisis.

State and federal organizations are already working to provide economic assistance to individuals and small businesses that have been impacted by the collapse. 

The governor said that while there's an urgency to move fast, crews have to be cautious.  

"We're talking about tons of steel that is mangled and cantilevered.  We're talking about water that is so murky and so filled with debris that divers cannot see any more than a foot or two in front of them," Moore explained. 

Four bodies unrecovered, aid sought for impacted workers

Eight people, part of a construction crew filling potholes, were on the bridge at the time of the collapse. Two were rescued, two bodies have been recovered, and four remain missing and are presumed dead. 

Moore says divers have not been able to go back into the water to search for the missing construction workers because of the weather and all the debris. 

So far, four of the victims have been identified.

"My focus is on making sure these families are getting the comfort and the closure that they need, making sure that our first responders are getting the supports that they need, making sure that we can get these channels open and making sure that we can get this Key Bridge rebuilt," Moore said.

On the CBS News broadcast "Face the Nation" Sunday, Scott said he plans to meet with labor leaders and workers at the Port of Baltimore on Monday to discuss ways to support them while traffic in and out of the port is closed.

"To talk about what kind of other supports that they need while we all wrap our heads around and figure out how we can support them and keep as much commerce flowing as possible," Scott said. "This is going to be a long road. This is not going to be a sprint."

Maryland lawmakers are drafting emergency legislation for income replacement to assist thousands of Port of Baltimore workers impacted by the disruption. 

President Biden to visit Baltimore

President Joe Biden is set to visit Baltimore on Friday, according to White House Press Secretary Karine Jean-Pierre.

The announcement follows Biden's vow last week to visit Baltimore following the collapse of the Francis Scott Key Bridge. 

The president also said he believes the federal government should pay for the bridge reconstruction. 

Cruise lines redirected 

Meanwhile, cruisegoers, including Zach Ocanas, are back in Maryland.

Ocanas left on a carnival cruise a week ago. With the channel closed, his ship had to dock in Norfolk Sunday morning, and passengers took a four-hour bus trip back to Baltimore.

Ocanas caught a ride with a family member who lives locally.

"We were like super on time," Ocanas said. "And they had like buses like waiting outside, like there was just a massive bus ready. All the Carnival staff was like ready to go and they had local police ready to go to kind of guide us to the buses and everything."

The Royal Caribbean's Vision of the Seas was set to leave out of Baltimore on Thursday, but will now leave out of Norfolk.

If you find debris, call the hotline at 410-205-6625.