Yard Drainage & French Drains in Shoreline, WA

For most of the city, yes, and the practical consequences are identical. The same glacial till underlies both, so flat Shoreline lots hold water for exactly the reason flat Wedgwood and Maple Leaf lots do — water reaches the hardpan, stops, saturates the shallow topsoil above and has nowhere to run. The differences are scale and exception. Lots here are larger, so systems are sized for a bigger catchment. And the ravine corridors and the western bluff behave nothing like the plateau in between, which is where the design conversation actually changes.

Not as a design we would offer. Bluff ground along the Sound carries looser material than the plateau behind it and is sensitive both to loading and to water, and taking every drop your garden collects and delivering it in a concentrated stream over the lip is precisely the mechanism that destabilises a slope over successive wet seasons. It converts a drainage improvement into a stability liability. On these lots the discharge has to be designed properly — routed to an appropriate point, with attenuation where it is warranted — and the parcel checked for critical area designations first.

The ravine is genuinely useful topographically and genuinely constrained environmentally, so both sides need addressing. On the useful side, real grade means discharge to daylight is achievable in a way it is not on the flat plateau. On the constrained side, creek corridors carry critical area rules and buffers, and a drain that discharges into or near one is a different proposition from one that daylights on your own ground. We establish what applies to your parcel before designing an outfall rather than assuming the fall is available to use.

Longer ones, and sized for the catchment rather than for the visible symptom — which is the mistake we most often correct on these properties. A wet corner on a twelve-thousand-square-foot lot is collecting surface and shallow subsurface water from everything above it on the property, not from the few square yards around it. A system sized for the puddle gets overwhelmed during the first sustained wet week and shows it by water travelling around the end of the run. We work out where water enters, where it concentrates, and how much ground feeds each point before specifying anything.