Magic in the Water (1995)

On vacation at a beautiful lake in British Columbia, Ashley (Sarah Wayne) and Joshua (Joshua Jackson), the children of workaholic radio host Jack Black (Mark Harmon), learn about its mythical inhabitant, a sea monster named Orky. Soon, the kids learn that Orky is not only real, he's attempting to communicate with humans to warn them that an evil corporation is illegally dumping pollutants into his home. They try to save Orky with the help of an elderly Native American (Frank Sotonoma Salsedo).