Yard Drainage in Chilliwack

Drainage starts with the source, because the source decides the method. Five sources account for almost every wet residential yard.

• Rainfall on the yard itself collects in any low spot without fall. A winter of Fraser Valley rain finds every hollow.
• Roof runoff concentrates water at each downspout. A downspout emptying onto the lawn delivers a roof's worth of rain to one patch of ground.
• A neighbouring slope sheds water downhill onto the yard below, at the surface and through the ground.
• A high water table pushes water up from below. On Agassiz and Harrison acreage the water table sits high for months of the year.
• Hard surfaces such as patios and driveways shed water sideways onto whatever sits beside them.

Each symptom reports where the water goes and how long it stays.

• Puddles lasting days report a low spot with no fall and subsoil that absorbs slowly.
• A lawn too wet to mow reports saturation across a wider area, often from a slope or a high water table.
• Water running toward the house reports grade falling the wrong way, which puts water against the foundation.
• Soil washing off a slope reports surface water running fast with nothing to slow or collect it.
• Moss and dead turf in one corner reports a permanently wet zone, wet under the surface even in a dry month.

Watching the yard during heavy rain reveals the path faster than any other test. The water shows where it enters, where it runs and where it stops.

Ground type decides whether water soaks in or sits on top. Clay-heavy flats, such as the ground toward Sumas Prairie in Abbotsford, absorb water slowly and hold it at the surface. Builder fill compacted by machines during construction behaves the same way, which explains why many newer subdivision lots drain badly despite looking level.

Flat grading leaves water with no direction. A hollow at the bottom of a slope collects everything above it. Agricultural ground with a high water table has little room below the surface to accept more water. On all of these, water has to be moved across the ground to an outlet rather than pushed into it.

• Regrading reshapes the surface so water runs away from the house and toward an outlet. It solves many wet yards without any pipe.
• A french drain places clear drain rock around perforated pipe in a trench. Water enters the rock, collects in the pipe and runs to the outlet. It suits yards where the grade cannot change, or where water arrives below the surface.
• A swale forms a shallow grassed channel that carries surface water along a planned line without pipe.
• A dry creek bed lines a channel with river rock. Graded to an outlet it carries water; without fall it only decorates.
• Wall drainage places drain rock and perforated pipe behind a retaining wall, because water trapped behind a wall pushes until the wall moves.

The outlet decides whether a drainage system works at all. Collected water needs a destination lower than the point of collection.

A pipe run out to daylight on a lower part of the property forms the most common outlet on sloped lots. A roadside ditch serves many rural properties. A municipal storm connection serves some urban lots where the local authority permits it. A rock-filled soakaway stores water underground and works only where the subsoil drains. A natural drainage path already on the property serves where it exists. Flat clay lots with no lower point present the hardest outlet problem, and the outlet often sets the length and cost of the job.

Standing Water In A Yard Is A Fall And Drainage Problem Rather Than A Soil Problem

Soil type sets how fast water soaks in, and fall decides whether it leaves. Giving water a downhill path to an outlet removes it from any soil. Replacing soil without creating fall leaves the water where it was.

A Drain Without An Outlet Only Moves The Puddle

Pipe and rock collect water. Only an outlet removes it. A trench with no exit fills during the first heavy rain and holds the water underground, out of sight and still saturating the yard.

Fixing Where The Water Comes From Beats Collecting It At The Bottom

Redirecting a downspout or intercepting a slope at the top costs less than collecting the combined flow at the lowest point. Source control reduces the size of everything downstream.

Regrading Solves Many Wet Yards Without Any Pipe

Surface water follows the grade. Reshaping the yard so the ground falls away from the house and toward an outlet removes standing water with machine work and topsoil rather than a buried system.

Clay Ground Holds Water At The Surface, So Water Has To Be Moved Across It

Clay absorbs water slowly regardless of depth. Drainage on clay works by conveying water along the surface or through a shallow collection trench to an outlet, rather than by soaking it away.

Misconception: A French Drain Fixes Every Wet Yard.
A french drain collects water and moves it. Without fall and an outlet the trench fills and stays full. On many yards regrading the surface solves the problem with no pipe at all.

Misconception: Adding Topsoil Fixes Standing Water.
Topsoil over a low spot raises the puddle rather than removing it. The water still meets the same subsoil and the same lack of fall underneath. Fall and an outlet remove water; topsoil hides it for a season.

Misconception: Water Soaks Away If The Drain Is Deep Enough.
Clay and compacted fill absorb water slowly at any depth. A deep pit in clay fills and holds water like a buried bucket. Moving water across the ground to an outlet works where soaking it in fails.

Misconception: Drainage Is Only A Problem In Winter.
Winter rain reveals the problem and summer hides it. The same low spot that ponds in November stays soft under the surface, kills turf and pushes on nearby walls and foundations year round.

Misconception: Drainage Work Ruins The Lawn For Good.
Trenches and regrading disturb the yard for the length of the job. Backfill, topsoil and new sod or seed restore the surface, and a drained lawn grows better than the wet one it replaced.

Filter fabric. One side wraps french drain pipe or trenches in fabric to keep silt out. The other cites fabric clogging in fine soils and relies on clean rock instead.

Regrading or pipe first. One position starts with regrading on cost grounds. The other cites the limits on reshaping a lot bounded by a house, a patio and property lines.

Dry creek beds. One side treats them as functional drainage. The other treats them as decoration unless graded to an outlet.

Soakaways on clay. One view treats a rock pit as useful storage. The other treats it as a buried puddle in ground that never drains it.

Downspouts. One side discharges onto the lawn for simplicity. The other pipes roof water away to keep concentrated flow off the foundation.

Yard drainage works by identifying the water source, giving the water fall and delivering it to an outlet lower than the yard. Regrading, french drains, swales, dry creek beds and wall drainage each suit different sites, and clay or compacted ground favours moving water across the surface over soaking it away. Standing water in a yard is a fall and drainage problem rather than a soil problem, and a drain without an outlet only moves the puddle.