gulch (n.) Look up gulch at Dictionary.com
"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].