Can I Kayak (the Harpeth River in Tennessee, Generally)?

This is a JavaScript version of my original implementation written in Python/Flask

Basically, I wanted a quick and convenient way to check on water levels on a river that I frequently kayak near my house, the Harpeth River, in Tennessee. I realize that this is probably only useful to literally dozens of people, but it's tricky to factor in all statistics that go into making these very non-scientific guesstimates based on the cubic feet of discharged water per second, gage height, and water temperature.

If you want to modify this for your own use, you can look up Site Numbers at the USGS here. Keep in mind it has to have gage, discharge, and temperature data, and even then, it still may not parse correctly. For this particular region, I got the first two data points from one site, and had to go upstream one station to get the water temperature.