The reason it takes off at 36 min is because the exit is lower making a vacuum siphon. Just found out what this man made pond was built for, it for cutting out ice blocks before electric refrigerators. This was for the real ice boxes that used a block of ice to keep food fresh

The excitement starts after 19:00 .I was fighting lots of water pressure but I found it easier to just let the leaves pass through by scraping mt feet and the rake back and forth. As I was raking it created an undertow moving crap from the bottom of the lake over instantly and that is what took so long, I gave this my own inspection 5 months back and the grate is safe but the underground pipe is not and It is in the process of failing. The rock I found may have just fallen in. This time I got before and after video of the end. A shovel would not work well for this job so stop commenting that