Sentence:  Rock Spring <WSD>Wash</WSD> continues a short distance then joins Watson <WSD>Wash</WSD>. Water from Rock Spring comes out of the boulder strewn <WSD>wash</WSD> and disappears into the sand 
Meaning of the word marked with <WSD> tags:  (dry stream bed) In arid and semi-arid regions, the normally dry bed of an intermittent or ephemeral stream; an arroyo or wadi.