The word streambed is playable in Words With Friends™, no blanks required. Because it is longer than 7 letters, you would have to play off an existing word or do it in several moves.
Words With Friends™ Letter Score: 16
Highest Scoring Words With Friends™ Play In The Letters streambed
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Seven Letter Word Alert: (32 words)
ambered, beaters, bedares, bedmate, bedrest, beermat, berated, berates, besmear, dearest, debaser, debater, debates, demates, embased, embread, readmes, reasted, rebased, rebated, rebates, redates, remated, remates, reteams, sabered, sedater, smarted, smeared, steamed, steamer, tasered