Caring for the environment

Find out more about the work of Sustainable Hertford Heath

Flooding

Why so many floods?

Storms are making their mark, we’ve just had Storm Dudley and Eunice blow through. Climate change means we will see more extreme weather events so that each year heavy, driving rain will increase the chances of flooding.

Hertford Heath is on the top of a hill, surely we don’t have to worry about flooding. Sadly we are not exempt, changes to our rural and urban landscapes mean that rain is hitting the ground at higher speeds and taking much longer to drain away, leading to an increased risk of flooding.

So sadly homes in Hertford Heath are still at risk of surface water flooding. This is where heavy rain falls onto already saturated or compacted ground or hard surfaces, runs across the surface and collects in lower areas. This effect is made worse if heavy rain overcomes the drains and can’t get away fast enough.

How can trees help with flooding?

As well as taking in CO2, offering cool shade and looking great they also help to reduce flooding in a number of ways. Here’s how they do it:

  • Canopy cover - the leaves, branches and trunks slows down the rain before it hits the ground simply by getting in the way.
     
  • Roots – Root systems help water penetrate deeper into the soil at a faster rate under and around trees, this means less surface run-off and more water storage in the soil.
     
  • Urban trees - In towns and cities, the rise in impermeable surfaces such as roads, pavements and driveways has led to increased surface water run-off. Around two thirds of all the flooding in 2007 was as a result of surface water run-off.
     
  • 80% - that’s how much more trees reduce surface water run-off compared to asphalt.

An increase in green space could drastically reduce run-off in built-up areas. The small patches of bare ground around street trees, known as tree pits, are sometimes covered by asphalt. Removing the asphalt is an easy way to improve water infiltration in urban areas.

In an already crowded street we may not have the room to plant trees but protecting the ones we have is a great way to help prevent flooding.

Hertford Heath Online logo

Hertford Heath Online is supported by a grant from East Herts Council

Image