Yard Drainage & French Drains in West Seattle

Because on unstable ground water is not a nuisance, it is the mechanism. Saturated soil is considerably heavier than dry soil and has much less internal strength, and that combination is what turns a slope which has stood for decades into one that moves. On the bluff that makes uncontrolled surface water, a downspout discharging over the edge, or an old drain that has silted up into genuine risk factors rather than maintenance items. Any hardscape we build on that side of the peninsula is designed around where water leaves the property first, and on several bluff projects the drainage has been the entire job.

It depends on the parcel and on what is being built, and it is worth establishing early because the answer differs from the plateau. A large share of the West Seattle bluff carries steep slope or landslide-prone Environmentally Critical Area designations, and inside those, work that involves excavation, changes surface water routing or adds load is treated differently from the same work on level ground. We check the parcel against the city map before quoting so the process and the programme are known up front rather than discovered once a trench is open.

That is the design question, and there is usually an answer — it is just rarely the obvious one. Options include routing to an approved connection rather than to the slope, discharging at a controlled point away from the sensitive ground, or attenuating and dispersing flow rather than delivering it as a concentrated stream. Which of those applies depends on the parcel, the designation and what is physically available. What we will not do is take the cheap route of daylighting a system over the lip and leaving the consequence to arrive in a few winters.

Considerably. On the plateau through the Junction, Westwood and Arbor Heights you have ordinary Seattle conditions: glacial till, water perching on hardpan, a saturated topsoil layer that will not clear between October and March. That is a well-understood problem with a well-understood answer — a drain cut to consistent fall, clean rock, geotextile, and a real discharge point. Access on these lots is generally reasonable, so the work is straightforward and priced accordingly. It is genuinely a different project from a bluff lot half a mile away.