Event Venue is what you're looking for. I updated it. Try searching osm.wiki/ in the future, it usually has answers to these types of questions.

You ended up making most of Indian Creek a culvert. In the future, you'll need to split the line at both ends of the culvert location before setting that section. I'm going to go ahead and fix it, based on the The City of Hood River, Oregon's Public Utility Mapping Application.

Eventually, but it'll take some work to complete the boundary lines since the gorge is so large. I have removed the multipolygon tags for now.