Thanks for that link. It was a very interesting read. The link in the article to the US Army Corps of Engineers web site with the National Inventory of Dams (NID) still works, and it says the data was now updated to 2016 (the article is from 2015, and then the data was from 2013). Here is the link from the NJ.com article:Even though it doesn't specifically mention Harrisville Dam it's a good read and I learned a few new things from it.
There is a search function by state, but it requires Flash plugin which I don't have/don't want, so I don't know if it works. The interactive map works. The NID does contain Atsion Lake Dam and Harrisville Dam, but not Lake Absegami Dam. All it shows is the owner, year completed, and last inspection date. The fact that a dam is in the NID means that it meets some criteria for hazard, but that's all you get.