Herby's Secret Formula by Sue C. Hughey

Budding scientist and avid Boy Scout Herby Strange is concerned about world overpopulation and has an idea to make more room for all the people and animals. While concocting a formula to shrink living things, he accidentally shrinks himself to a height of six inches. Herby encounters one unfortunate and entertaining predicament after another, which he faces with bravery, resourcefulness, and determination. He is kidnapped for ransom but escapes into a mountain wilderness teeming with wild animals. He spends several days in a deserted campground building a boat from trash so that he can sail to the marina across the lake and find help. Herby survives the crossing, but is caught in the current going over the spillway, and is swept down and onward to further adventures. Only his own ingenuity and the skills he learned in Boy Scouts, save Herby from the many perils he faces on his long journey back home.