Ice fisherman rescued after falling into Mantua Reservoir A man and his dog were rescued Monday after falling through the ice at Mantua Reservoir in Box Elder County. Posted at 9:52 AM, Dec 14, 2020 and last updated 2020-12-14 19:49:49-05 MANTUA, Utah â A man and his dog were rescued Monday after falling through the ice after attempting to ice fish at Mantua Reservoir in Box Elder County. The Mantua Police Department responded to the area where the 66-year-old Plain City man was reported to be drowning. Upon their arrival, officials saw the man and dog struggling in the water. "He was just fighting for his life," said Mantua Police Chief Michael Castro. "He was stating that he was tired and didn't want to pass."