30. Rain Planter: Alma Primary School
Themes: Water quality; Biodiversity; Getting people and communities engaged
- Reduce the frequency and severity of pollution
These 'Rain Planters' take rain water from a roof via the existing downpipe, the water infiltrates slowly through the planter and is used by the plants.
London's sewer systems were built to cope with a much smaller population than exists today. When there is too much water in the sewers they are designed to overflow discharge raw sewage directly into our rivers. This happens on a weekly basis.
In addition to this, each year in London an area of green space the size of Hyde Park is paved over, rain water that would have sunk into the ground naturally now runs off these impermeable surfaces and enters the sewer network. This increases the amount of water in the sewers further, and so increasing the frequency and amount of untreated sewage which enters our rivers.
Thames21 have commissioned a design of a basic sustainable drainage system that can be built without the need for ground excavations, from off the shelf materials and at a relatively low cost. These 'Rain Planters' take rain water from a roof via the existing downpipe, the water infiltrates slowly through the planter and is used by the plants, reducing (or slowing) water entering the sewers. An additional benefit of these systems is that they have the potential to reduce downstream flood risk.
As part of our Love the Lea project, we are installing these 'Rain Planters' at schools coupled with our free curriculum-based river education sessions.