Slide 1 Subsurface Drainage Systems Wade Armstrong Luke Doubleday Brette Hennig Tyra Stanich Declan Klapp Slide 2 When do we need a subsurface drainage system High water tables Extremely coarse textured soils (golf courses) Bases for permeable pavement and patio’s When we want to remove non capillary water from the upper layers of the soil profile Slide 3 Common indicators of poor subsurface drainage Large puddles of pooling or standing water (saturated soil) Excessively soggy spots in your yard Random overgrown patches of grass Water pooling underneath downspouts Water stains on the foundation of your home Slide 4 Common causes of poor subsurface drainage Compacted soil Improper sub surface grading Poorly maintained eavestrough and downspouts Improper installation of landscape features Slide 5 Solutions: Types of Subsurface Drainage Systems Ground water pumps Interceptor drains Mole drainage Slotted subsurface pipes Culverts French drains Proper Grading Slide 6 Ground Water pump What is a Groundwater pump? It is a device used to extract water from water-bearing sand strata in the ground. How it works? The motor powers impellers, which turns the Water upwards. Turning the pressure switch on causes the impellers to spin, causing water to be sucked into the pump. The water gets pushed through the body of the pump, then into a storage tank above the grounds surface. It is commonly most found in your basement the pump pushes the water away from the house. Slide 7 Interceptor Drains Used to collect, channel and remove horizontal moving surface and subsurface water within permeable soil as it flows across an impermeable soil layer They are installed at the bottom of slopes where the steeper slope meets the flat to intercept the downhill flow of horizontal moving water. Often the soil on the slope is more permeable than the soil on the flat portion. This forces the water to the surface. Used to remove water where soils are saturated. Slide 8 Mole Drainage Mainly used in New Zealand and UK in heavy soils where downward movement of water is prevented by compacted clay subsoil Mole drains are unlined channels in compacted clay subsoil; they drain water as it enters from the surface Can be used over a collector pipe system when in sandy areas, very heavy clay, or there is a great distance to reach an outfall; uses slotted subsurface drainage pipes Slide 9 Slotted Subsurface Pipes Also known as “Drain Tile”, slotted subsurface piping is installed under the topsoil surface and a filter sock is placed on to prevent any sediment from entering the pipe. Best suited in permeable soils and soils with an interface layer Slide 10 French Drains Trenches dug and lines with landscaping fabric, filled with rock (with an adequate slope) can be designed to appear as a dry riverbed or just covered as a way of drainage that can be appealing in the landscape as well