Yard Drainage & French Drains in Kirkland, WA

Practically, the water is in your garden, so managing it is your project — but how you manage it matters. The effective approach on a downhill lot is interception rather than collection: a cut-off drain across the upper boundary that catches flow before it reaches the area you are protecting and routes it around, so you are not trying to collect water that has already spread across the whole garden. That is usually a shorter run and a smaller system than the alternative. Where a neighbour's hard surface or downspout is concentrating flow onto your ground, that is worth a conversation with them before it becomes an annual expense.

Two of the three things a drain needs are in short supply there. A drainage system works by collecting water and carrying it, on a consistent fall, to a point where it can discharge — and the low ground at the north end is flat, which limits available fall, and sits close to a high water table, which limits how deep a trench can usefully go before reaching saturated soil. Neither makes drainage impossible. It does mean the discharge point has to be established before anything is designed, and it is one of the few places locally where we occasionally recommend regrading and surface management over a piped system.

Almost always silting, and almost always because there was no geotextile. A French drain carries water through the void between clean washed stones. If the surrounding soil can migrate into that rock — which it does steadily over years without a fabric separating them — the void fills with fines and the drain becomes a buried line of wet dirt. The second common cause on a slope is an inconsistent fall: a trench that dips somewhere along its run holds water in the low point, which then collects sediment and blocks. Both are construction faults rather than age, and both are why we specify what we specify.

Largely, yes, though on the steepest lakeside lots it takes longer because a machine may not be able to reach the line. What we plan around is the reinstatement: turf, planting or hard surface put back so the finished job does not read as a scar down the garden. On a slope there is an additional consideration, which is that a trench backfilled with free-draining rock is itself a route for water. Cut on the wrong alignment it can carry water somewhere you did not intend, so the fall and the outfall are worked out before the first spade goes in.