Mee Shee: The Water Giant

MeeShee The Water Giant is an AngloGerman family film shot in New Zealand and released in 2005. It stars Bruce Greenwood, Rena Owen, Tom Jackson North of 60, Shining Time Station and Daniel Magder.

A United States oil company loses a drill, intended to do work in the Arctic, while flying over a Canadian lake. Company employee Sean is contacted to go to Canada to find it however, he has to cancel plans to take his son to Walt Disney World. Although his son, Mac, is disappointed, he agrees to go with his father to Canada. Once in Canada, they meet a local native named Custer who helps Sean and another employee on their mission.They visit the lake using a submarine, and after taking pictures of the bottom of the lake discover incredibly deep giant rivers. The legend of MeeShee states that the rivers lead to the ocean. Sean and Mac rent the home of Mrs. Coogan, a kindly lady whom Sean refers to as Mary Poppins. ........

Source: Wikipedia