Practical notes on how to save water on...

Thursday, 24 January 2013

Forget drought -what about flooding?

With the cold winter in England well underway and all the flooding of 2012 just behind us I don't feel like writing about saving water, it is a summer subject, it's hard to get excited about saving water in the winter... or is it? Water saving devices, greywater recycling and rainwater harvesting not only reduce drinking water demand (which is great news in a drought) but also REDUCE the risk of flooding. Hooray! This is because reducing the flow of water in drains increases the spare capacity in the drainage network for coping with sudden surges in rainfall.

This is why the BBC is posting slightly crazy articles like: "Snowmen hold back flood " and why the RSBP are promoting rain gardens. A what? A rain garden is basically a soggy patch in your garden intended to get flooded, full of plants that like a good soaking, sited directly in line with the rainwater downpipe from your roof.  This holds water, prolonging the journey time to the drainage network or the nearest river. The more water soaking into the ground, the less water being handled by the drainage network.  This is the basic concept behind SUDS or Sustainable Drainage Systems, which reduce water flow rates from car park areas, by providing a road surface that allows water to soak directly into the ground rather than being collected in surface water drainage pipes which take water to a water treatment works.  During a flood, the underground drainage network can get overwhelmed with the volume of water running off roads and roofs, causing raw sewage to pour into nearby rivers and canals. If a river busts its banks... no prizes for guessing where the sewage goes next. So if you are worried about flooding:

[1] fit water saving devices, like tap flow restrictors
[2]  fit a WATERTWO and use your greywater (see my post on this)
[3] fit a water butt, and use your rainwater (see my post on this)
[4] when it snows -BUILD A SNOWMAN !! But more importantly clearing your driveway and creating a pile of snow on the edge of your lawn you are slowing down the melting process.
[6] get all horticultural and plant yourself a rain garden
[7] maybe skip that swim in the Manchester Ship Canal

for more info on rain gardens