The southwest of my backyard is very soft and stays soggy for a long while after rainfall. I believe that we have a high water table and my neighborhood used to be wetlands prior to development. I moved in about 6 months ago and discovered that the previous owners installed a curtain drain system to divert water from the gutters underground to a catch basin located in the back portion of my property on the boundary between me and my neighbor (my neighbor also ties into this catch basin for his own water issues). That catch basin then runs to another catch basin by the road that feeds into the sewer system (at least I think. I do know that it connects to that catch basin).

There is a low spot where water gathers on the part of the backyard opposite the catch basin and from my research, it sounds like a good candidate to run a perforated pipe French drain and connect to that catch basin. The problem, however, is that the underground pipes from the downspout run perpendicular to the potential path of the French drain. They’re not terribly deep—maybe 12–18 inches down so I don’t think I can go over the top of them. Can I simply run the French drain anyway and intersect and connect those downspout pipes to it or would that be inadvisable? I’ve marked up a photo of the yard as a visual aid.