Concrete pipe,not slippery at all,the walls reach the floor with an sharp angle but it's mostly flat at the bottom.....
For D-v-S it's knee high but for me it's thigh high...strong current makes the walking a bit slow....We suspect a mix with sewer...smells a tiny bit.Shreaded toilet paper,a condom passed by but it was not a disgusting water...would'nt like to fall in 'though..