Thanks for the advice, it's definitely nice to find out a plan is wrong before you enact it rather than afterwards. If I may ask a few follow-up questions, is this a bad idea because the location of the french drain will encourage water to seep underneath the concrete, leading to damage, or because digging the soil out immediately next to the driveway will undermine the concrete and decrease its strength? I ask because I fear that I already have water seeping underneath the driveway and can't think of another way to fix it. The concrete is already cracked in several places, and I'm looking for a solution that will last a few years before ultimately the whole drive has to be replaced. The house is fifty years old but I have no idea how old the driveway is. Thanks again, I appreciate any advice.

If I understand your proposed scheme, you're going to create a subsurface, gravel-filled trench across the drive and imbed a channel drain in its upper portion (which is the driveway)...? In theory it sounds reasonable, but I suppose in practice, that's a lot of hole-drilling to actually make into that channel to handle the volume of water. Drains have away of silting and clogging up as though it's their objective. Seems like unless the holes were sizable and numerous, the drain could fail. Then again, a french drain is subject to failure after a while due to silting up. Then again, if this drain fails completely, the only downside is that the effort and expense of creating it come to a premature demise. I consider french drains a last resort because of their limitations. Being filled with rock, they're inefficient in how much material their construction requires relative to their capacity to store water. Seems to me it would be much more efficient to have a sturdy underground storage vessel that was strong enough that it didn't need to be filled with rock... then to have a conventional water collection and piping system (like a trench drain with no holes and some 4" pipe connecting to it.) I'm thinking that a buried section of standard concrete pipe could be fitted for use as a retention device...kind of like a cistern that leaks on purpose. It would not need to be near the size of a french drain to hold the same amount, or more, of water. It would not need to be located directly under the drive. And I think it would be much cheaper as the pipe itself is not expensive. They're a little heavy to move, but not impossible. This is a little tangential but for fun, here's a link to a video that shares some secrets of manually moving very heavy objects. Here is a link that might be useful: Guy explains moving very heavy objects

LeBox, I'm sure you understand this is a complex issue. I can offer comments but not assurance that all important factors are accounted for. I hope you get a local review of your plan in order to prevent work being done that falls short of solving the problems. Let me mention some possible issues. In a large rainstorm, the volume of water running off the hillside could be considerable. As it will be caught in the swale at the top, back of the wall, the swale needs to be calculated to handle the volume of water for a large storm. As the swale is located at the north half of the property, would it be better to drain it off to the north side of the property instead of having it go the longer distance around the south end of the house? If possible, I would have the goal of keeping this surface water at the surface instead of putting it into a pipe. (Sometimes it's not possible.) If it's on the surface, one doesn't have pipes clogging in the middle of a storm and failing. If it must go in a pipe, the pipe needs to be calculated to handle the flow of the design storm. Frequently, homeowners think 4" pipe will do everything but it is often inadequate. You would not want to run this water coming off of the hillside into the existing drain system of the patio (feeding a larger pipe -- at least it should be -- into a smaller one.) You might end up doing the reverse ... running the patio drain into whatever drains the hillside surface. The section of the drain behind the wall looks fine. The purpose of the collector pipe behind the wall is only to get rid of water that infiltrates the soil behind the wall. You would not want to add any drainage water to it or simultaneously use this pipe to drain any surface water through it. Though you could drain this pipe into a larger pipe or swale that is draining surface water, so long as it is calculated to handle the volume. (The volume of the water collecting behind the wall will be small relative to the volume that is draining from the yard surface.) "Arms of surface drains extend to edge of patio w/riser" ... the only purpose I can see for these is as yard drains at the edge of patio, though I wouldn't know what volume of water to expect in this area. As yard drains, inlets would need to be slightly lower (2") than the patio surface with the surround grade pitched downward toward the inlet. This type of drain is subject to clogging from yard debris so requires regular cleaning of the inlet and possibly a cage over the drain to filter out debris. Usually, groundcover of some type helps to keep surrounding soil from washing into the inlet. Summing it up, you have 3 separate drainage systems: 1. swale behind wall ... this is largest volume of water. 2. existing patio drain w/ attached yard drains ... this is second largest volume of water. 3. collector drain behind wall ... this is least volume of water. lower volumes of water can run into systems handling higher volumes of water, but not the other way around.

Thanks. The concrete around the edge doesn't seem very thick since they put that system in (B-Dry) Thus my sorry about attaching to it. Watching a video where they were bolting in the baseplate I thought that wouln'dt work in my situation. There has never been a water issue since they put that in, nor since we have lived here 6 years ago. Sumps pumps (2) work great during the winter thaw. My fisrt step will be to wall up around the stairs for a kids area with a secret door (bookshelf) Then I will tackle the outer walls.