Identify rather the underlined clause is an adjective clause adverb clause or noun clause after they had traveled for several years the people settle near the freshwater source.

after they had traveled for several years - adverb clause

Explanation:

The clause "after they had traveled for several years" is introduced by after, which is a subordinating conjunction of time.

The clause "after they had traveled for several years" is  an adverb clause of time.  

explanation:

the silver bells of the sleds are merry and keep time in the winter nights while the sky twinkles happily. the golden bells of weddings are delightful in their peaceful happiness, foretelling a rapturous future. meanwhile, the brazen alarm bells scream frightfully in the night, with a discordant and desperate sound. in their clamor, these bells convey terror, horror, and anger. finally, the iron bells are solemn and melancholy, while those in the church steeple are like ghouls who feel happiness. the king of the ghouls, who rings the bells, cheerfully keeps time with the moaning and groaning bells.