refine scrolling

[cnell-usgs]

The scroll time is rather long if you press on any of the navigation buttons, and comes to a very slow scroll when reaching the end point. This could be a bit more efficient and easy to use.

Also consider:

• adding a navigation to the top of the page
• adding navigation buttons for all sections, including references etc at the end
• the top menu could be "Five droughts that changed history: Dust Bowl; ....; Turn-of-the-Century Drought; Methods; References"

[cnell-usgs]

The pop up menu is distracting when it's empty, and at times competes with other text and annotations on the chart:

What if in the beginning it said "How to read this chart" and these annotations are added to the pop up instead of directly on the chart?