Idea of Hot Springs Icon
This is an image of a puddle of water made out of three circular lines. The bottom line is rather broken, the middle line is semi-circular shaped and the inner line is almost a complete circle. In the center of the innermost circular line are three vertical wavy lines.
This page shows the different variations of the Hot Springs from an Icons8 icon pack. Feel free to resize and recolor the icon, and then download the icon in PNG format for free.