PLACE meat in slow cooker; top with vegetables and barbecue sauce. Cover with lid. Cook on LOW 7 to 9 hours (or on HIGH 5 to 6 hours).
REMOVE meat from slow cooker; cover with foil. Let stand 10 min. Meanwhile, remove vegetables with slotted spoon to serving platter; cover with foil.
MIX flour and water; stir into liquid in slow cooker until thickened. Slice meat; add to platter with vegetables. Top with gravy.