As summer's heat arrives in Central Oregon, local officials are warning the public about the dangers of swimming in irrigation canals.  Central Oregon Irrigation District Manager Steve Johnson and Bend Police Sergeant Ron Taylor spoke to News Channel 21.  "It does look slow, but it's difficult to get out," said Johnson. "There are obstructions in the water that people can't see. The most recent drowning was several summers ago in Bend."  "It was obviously very tragic," said Taylor. "Tragic for the family, and something that no one would ever want. But it just shows that water safety is something that we always need to have on the forefront."  Sgt. Taylor answered the call when a toddler drowned in the water.  Every spring, county officials visit nearby elementary schools to go over canal safety with children.  They also remind you to keep your pets away from the canal because they too can easily drown.