Now that the rain has finally arrived I can see the garden turning green again and absorbing every drop. As I sit here listening to the rain (wrapped up warm with my first cold of the season), I’m reminded of how so much of the water falling right now in this city is falling on the roofs and concrete, then piped straight down the drains into the harbour.
One of the issues is the contaminants that storm water picks up. Because our storm water is not treated before it is released into the sea these pollutants can have a bad effect on the marine & animal life and water quality of our shores. An overload on the storm water system can cause flooding and erosion of streams with the huge volume of water that surges through it in a high rainfall event, but also it can impact the sewer system (as there are still some combined systems around) flushing this onto the local beaches as well.
Rain gardens, not only look good, but are a way of taking the runoff from hard surfaces of the urban environment (footpaths, roads, driveways, carparks), and directing it to a garden bed of native plants (rushes, flax and grasses) that slowly filter out the many contaminants it picks up along the way instead of releasing it directly into our waterways, harbours and rivers. The idea of letting the rain return to the earth, have it filtered naturally, and let it top up the ground water just makes sense. Fortunately our local authorities are starting to see this too and are supporting ways that this can be incorporated into your urban house design and also in new commercial developments and parks.
Rain water tanks also slow down the progression of rain water from roofs into the storm water system, but you can use this precious resource to save you money. By sizing the urban water tank correctly it can be used for watering the garden, washing the car, washing your laundry and flushing the toilets. Seems crazy (in many parts of NZ) to be paying for using treated drinking water for this purpose doesn’t it when the water you need is landing right over your head!
So wrap up warm, and enjoy the rain after such a dry summer – I’m really glad it’s here (although you may want to ask me if that’s still the case in a few months time…I have a feeling now it’s started it may not stop for a while….!)
Photos of the Auckland Botanic Gardens – Rain water garden.