I recently purchased a house by Lake Erie which has a crawlspace foundation. There are existing drainage trenches throughout it dug into the hard clay, which all drains to a sump pump. These trenches are not maintained, and have built up over time with debris and now have standing water.
As part of my renovations, I plan to lay down a moisture barrier and seal the crawlspace as best I can. I was recommended to fill the existing drainage trenches with crushed stone, but after getting a quote for how much that would cost I am now wondering how necessary that is. What are the downsides of just leaving the existing trench system, and laying the moisture barrier over top of it? The crawlspace would be almost never accessed.