gulch n.

"deep ravine," 1832, perhaps from obsolete or dialectal verb gulsh "sink in" (of land), "gush out" (of water), from Middle English gulchen "to gush forth; to drink greedily" (c. 1200). Compare gulche-cuppe "a greedy drinker" (mid-13c.). "There appears to be no etymological connection with gully" [Century Dictionary].