To predict the future all you need is a rain gauge and a little imagination. Unfortunately the people who stand to gain the most by denying reality ... gain the most.

In addition, the map of western watersheds is amazing. I would love to see the other one the article mentions.

edit: couldn't find that, but did find Powell's 1878 report https://pubs.usgs.gov/unnumbered/70039240/report.pdf.