David and Thomas Goonery set out from Motherwell to explore the Clyde Valley, but as they passed Garrion Bridge they became aware of shouting and screaming and headed in the direction of the commotion.
David said: “Initially we thought it was just the sound of people playing down by the river, but as we got nearer it was apparent that something was wrong.
“We could just see a pair of hands sticking above the water and Thomas immediately dived in and headed towards them and I quickly followed him.
“Thomas managed to pull the boy back above the water, but he was already unconscious, so we pulled him over to the bank and lifted him out.
“I started to push on his stomach and eventually all this water came pouring out and he started to cough and splutter.
“We called an ambulance and said we were about halfway between Garrion Bridge and Rosebank Garden Centre and they were able to find us in about 15 minutes and take him to hospital.”
David and Thomas found out the boy is 11-year-old Corrie Osborne who had been camping with family further along the river.
David said: “We understand some of the people with Corrie had tried to jump in and rescue him, but the current was just too much for them
“It’s so lucky we came along when we did and were fit enough to be able to cope with the conditions as even just another minute or so might have been too late, which is something you don’t really want to think about.”
Corrie spent several days in hospital, but is on the mend despite his ordeal.
David said: “Thomas called the hospital on Monday and they said Corrie was doing well, which was so great to hear.”
Latest figures from the Royal Society for the Prevention of Accidents (RoSPA) show that in 2014 40 people drowned in Scotland.
Scottish Water is urging people to stay safe and not take risks around rivers, reservoirs and lochs this summer.
Chief operating officer Peter Farrer said: “Safety is a serious issue as while the water may look harmless there are many hidden dangers and we need to ensure everyone is aware of these hazards.
“We are reminding parents to keep their children safe and asking adults to act responsibly around watercourses.”