The water in the pond is actually from an underground river.
A boat lies at anchor along a plank walkway and is probably used to take visitors to explore part of the downstream cave. While we were there, however, no park employees were around.
The waterfront plank path connects two caves. We walked into the upstream cave and scaled a steep stone passage for several hundred meters.
Outside the cave, we found ourselves back at the upper part of the sinkhole. Along a path built on the cliff, we continued our walk until we completed a full circuit of the sinkhole. Later, I discovered that the funnel is actually a karst system with four caves and two underground rivers, including one stretching underground for several kilometers.
We met just several tourists during our three-hour stay at the site. Quiet and beautiful, with cheap admission, the Hou'er Sinkhole is definitely worth a closer look.