I imagine it was the Powell trip. First trip assuming it was white euro-descended folks. (They pat themselves on the back for being the first but I imagine it's reasonably touted as "first recorded") Just started a book on water rights in the American west (Cadillac Desert) and they touch on the trip as a sort of harbinger about the inauspicious-ness of irrigation and potable water sources out here, west of the Rockies. It's amazing they got as far as they did, right? Although apparently the party split up (arguably disastrously as some were never heard from again), a good portion lived to tell the tale. That Powell character was, among other things, the 2nd director of the U.S. Geological Survey, one of the few institutions without ... ah, I guess I can't reasonably claim there's no blood on their hands. It's all over the place here in our arid chunk of North America.
. One from Elvis to start, co written with former wife and Pogue, Cait O’Riordan. From his fantastic 1989 album Spike. Hope to bring summat from Nick later in the week. 
