It comes after six people ended up in the Walsall Basin, near the New Art Gallery in the town centre, in the latest of a series of incidents on Tuesday.
Similar incidents have been happening for decades, but the problem has got worse in recent weeks according to workers at nearby restaurants and bars. Last year a buoy was installed in a bid to raise awareness, but this has not prevented passers-by from needing rescuing from the water.
Two young children were among those who fell into the water near Costa Coffee, Bar 10 and Piro Fino within minutes of each other this week, with four people needing hospital treatment.
Lynn Allen, who works at Costa Coffee, said the problem was due to the layer of algae on top of the water which looks like turf meaning people mistake the water for a walkway and fall in.
She said: "I've fished a few people out and, in 2017, I did report this to the Canals and Rivers Trust after an elderly woman fell through the ice, but they told me there's nothing they could do.
"What they need to do is put bollards all along the waterside and a chain for the boat owners when they tie up here.
"That would stop people going in there as if they walk up and feel a bollard and chain, they'll know not to go any further."
Bar 10 worker Donna Harrison said there are not enough warnings in and around the canal and spoke about what she thought should be done.
She said: "I think that to stop people going in, they should put railing all around the edge and warning signs as well.
"I'm annoyed with the canal trust as I've been in touch with them and they've said there's nothing they can do about it.
"I've asked for life rings in here and the other places and mentioned railings to them, so I'm waiting to hear more."
The Wharf is an open basin where boats can moor but has become notorious over the years for accidents which have left people seriously injured.
There have also been incidents of people driving cars into the canal after mistaking the algae for an artificial surface near a flooded car park.
There is no fencing or railing blocking access to the water - although Ms Allen did put tape across bollards after the latest incidents to try and stop the number of people falling in.
In 1999, pensioner Sidney Drummond drove into the canal after mistaking it for a flooded car park and had to climb out of his sunroof.
Meanwhile, in 2007, a businessman drove his BMW into the canal, escaping while it bobbed up and down in the basin.
A spokeswoman for the Canal and River Trust said: "We’re sorry to hear that a group of people have fallen into the Walsall Basin as this must have been an awful experience for everyone involved and we hope they all make a quick recovery from their ordeal.
"To improve safety, and to remind people to stay away from the edge, a safety buoy has been installed in the middle of the basin warning local people that the water is deep and to take care when walking next to the basin.
"We are aware that there is a section of the basin covered in weed making it look like thick grass, hiding the water underneath.
"Although a lot of the weed has already been removed, dealing with the weed is an ongoing issue as it grows quickly and is difficult to control.
"A team from Canal and River Trust along with local volunteers will be out in the basin removing more of the weed in the next few days."