I'm in the process of installing a drain. It's going behind a house to catch surface water coming down the hill towards the house and drive. I'm planning on a 24"x24" trench filled with filter rock and no pipe. The trench will be 100'-125' in length and has a natural fall to it all ready. about 1/3 of the trench will be dressed with 3/4 inch river rock on top of the filter rock at grade level because it is the walkway from drive to back porch. The other 2/3's is going to be underneath the drive so will be dressed with #57 or crusherrun at grade level. My question is will this work and drain the water off properly or should I consider doppin in some drain pipe?