Drainage Systems for Your Garden
Excess storm water can cause flooding, soil erosion and can badly damage your landscape, that’s why having a good drainage system in place is so important. When it comes to getting rid of storm water, there a few different drainage options you can use.
An effective solution for draining the entire lawn would be field drainage. We recommend digging several trenches in a herring bone pattern to avoid wet patches, which follows the gradient of the lawn. You would then lay the trench with filter mat, Novacoil and then add drainage metal, then wrap this in a filter sock to further avoid the soil clogging up the Novacoil, and to stop pollutants contaminating the water. You can then lay topsoil and lawn seed. Water floods the trench then enters the pipe and flows away.
A soak hole is a good option for getting rid of storm water quickly. We recommend digging a large hole at a low point of the property and fill it with drainage metal, with a drain pipe leading down to it.
If digging a hole in your garden isn’t a possibility, a rain garden could be an effective alternative. Rain gardens slow down storm water flow and help purify the water. Rain gardens not only look pleasant, but act as a living filter and are an inexpensive, environmentally sound solution for drainage.
Storm water is full of pollutants. Not only is it water running off your roof, but from driveways, roads and other hard surfaces which can contain all sorts of nasty contaminants. Eventually our storm water ends up running into creeks, rivers and even the sea, harming aquatic life and promoting water impurities – A rain garden can help prevent this as it filters more even effectively than standard lawn drainage.
Before you create your rain garden you must first locate the ideal area to place it. You will want to place the garden where run off storm water naturally occurs, or at the base of a down pipe. Do not plant the garden within 10 feet of the house to avoid moisture issues and avoid planting too close to the septic tank. You will also want to be aware of any underground wiring or utilities before you dig. You will need to dig two test holes at around 20cm x 20cm. Fill them up with water and they must fully drain within 24 hours. Avoid planting the garden in this area if it does not drain in this time, as this will create an attraction for mosquitos.
The size of your rain garden will depend on the size of your property and the amount of water being captured. However big you make it, the ponding area will need to be between 200-300mm below the surrounding hard surfaces. You will want to fill the hole with rain garden soil mix and you can include a sand layer for additional storm water if you think you need to. You can place either a layer of rocks, pebble or mulch on top of the ponding area to prevent weeds and the soil drying out. If you feel you need it, you can also lay a perforated drain pipe underneath this whole, as well as a installing a small cesspit in the middle of the ponding area – This is for excess flowing storm water.
The ideal plants for a rain garden are natives, as they can survive extreme wet and dry conditions. Plants help filter out the pollutants and look appealing.