# But my brothers have acted as deceitfully to me as a desert streambed

"But my friends are unfaithful to me. They are like a desert streambed". Job speaks of his friends as being like a "wadi" which is a stream that can suddenly dry up and his friends ironically here as his "brothers." 

# as channels of water that pass away to nothing

"like streams of water that dry up." Job continues speaking of his friends being unfaithful.