MONTCHANIN, Delaware (WPVI) -- Eleven people were rescued from the Brandywine River on Sunday night.Police said the night started as a tubing event in Chester County, Pennsylvania. The group slowly made their way down the river when nightfall quickly approached.The group became stranded on rocks around 9 p.m., but they were able to call 911.It took firefighters about an hour to get to the group and then bring them to the Smith Bridge in Montchanin, Delaware around 11 p.m.Officials said the tubers were treated for hypothermia on scene and are expected to be OK.