Police Scotland's Dive and Marine Unit have been at the scene from Wednesday and through to Thursday after officers confirmed that a recovery operation is underway following reports of concerns for a man in the water at Threipmuir Reservoir.
BBC have reported that the man in his thirties was in an inflatable boat with about six male friends when the accident happened at 5:35pm on Wednesday at the reservoir near Balerno in the Pentland Hills.
An open-water swimmer said he helped guide the boat back to shore at the popular wild swimming spot.
The swimmer told BBC Scotland: "I arrived at the reservoir at 5pm and saw a bunch of guys getting into a dinghy. It was a huge, chunky dinghy and they were having a good time but weren't over the top.
"I swam the length of the reservoir and on my return back I could see they had crossed into the middle of the reservoir where it is at its deepest.
"I could see they were waving their jackets so I swam out to them and that's when I could see they were hysterical and saying their friend was in the water.
"I wasn't sure why they hadn't pulled him out and couldn't see him so I guided the boat with them in it back to shore. It was very windy and so it was choppy and they only had paddles, they didn't have a motor."
The latest statement from the Police Scotland has confirmed they are keeping the family of the man informed about their operation as they continue their recovery operation.
Chief Inspector Scott Richardson said: “A recovery operation is underway at Threipmuir Reservoir near Balerno today (Thursday, 15 July) after a man was seen to get into difficulties in the water on Wednesday, 14 July.
“Emergency services responded to the scene around 5.35pm and searches were carried out. These continue today and the man’s family are being kept fully informed.”
Pentland Hills Regional Park announced that there is no access to the reservoir and have asked that those accessing Harlaw Park do not attempt to access Threipmuir reservoir.
The park has recommended avoiding Harlaw altogether.