The so-called “blue canal” is located just east of the Bonneville Salt Flats in western Utah, and is leased by mining company Intrepid Potash, which uses the canal as a drainage ditch.
The canal first came to prominence last summer when an Instagram user posted images of the stunning blue waterway that went viral.
Thousands of people have since visited the canal to swim and take their own photos for social media.
Matt Newey posted a video and three images of the canal in mid-June last year. The video has received 27,000 likes.
Mr Newey wrote in the description of the images posted on 18 June: “Who knew this aqueduct near the Bonneville Salt Flats would be so fun to kayak. The water is so salty that it allows you to float effortlessly.
“The aqueduct’s purpose is to transport saltwater to nearby evaporation ponds where potash is extracted and used as fertilizer. Some believe the Salt Flats are shrinking due to this mining operation.”
In a late January update, he added: “As of [28 January 2021] the canal is full of water. For anyone concerned about our safety, I called [the Bureau of Land Management] and they told me that the water is safe to swim in because it’s only fresh saltwater that comes from the ground below the salt flats.
“They also said the majority of the aqueduct is legal to swim in because it’s on public lands. The reason why the media is claiming it unsafe is because people have been irresponsibly parking on the side of the freeway or getting stuck in the mud.”
Agencies were alarmed to see people kayak and swim in the canal, with Utah’s Bureau of Land Management issuing a statement, saying: “The canals are industrial facilities leased to Intrepid Potash for potash mining activities and are not designed or safe for public recreation.
“Therefore, the public should not access, swim, float, kayak, canoe, or pursue any other recreation activities in these industrial canals.
“In addition, the Utah Highway Patrol has indicated that parking along I-80 to access to the canals is illegal and extremely dangerous due to the proximity to the interstate highway.”
According to Brenda Bowen, a geologist at the University of Utah, “the water is not toxic”. She told The Daily Beast last week: “This is not to say you should drink it or really even swim in it, but it is definitely not filled with carcinogens.”
Officials have shown concern about large numbers of people illegally parking on the side of the nearby highway, which has a speed limit of 80 miles an hour.
Utah Highway Patrol said in a statement last summer that “there is no lawful way to access the canal from the interstate...To lawfully access the canal, one would need to park at the rest area... and hike the nearly three miles from the rest area to the canal”.
Dr Bowen told The Daily Beast: “The public just assumes you can go anywhere, especially with this massive culture of driving all over the salt.”
Mr Newey told the outlet that when people first found out about the canal, the shoulder of the highway “looked like a Disneyland parking lot”.
The Bureau of Land Management’s West District Manager, Kevin Oliver, told the Salt Lake Tribune that the canal is “not appropriate for recreation due to industrial design and other unknown hazards”.