When I first moved in, there was a ton of rocks down the side of the deck and back than I wasn't very smart (even now not to much) but I removed all them so I could build what I wanted and just ignored them over time I have learnt that it was in fact a dry river bed, so after a few years I put the rocks back into a different area more under the deck than along side it since I do still have the path there.

Really hopping it will help with slowing the water down and using the drain I put in, I know the height is wrong but this is the height I could achieve with the existing drain line thats the lowest I could do.