Heavy rainfall in July 2007 caused widespread basement sewer flooding in Hammersmith & Fulham and Kensington & Chelsea. A number of properties also flooded during storms in 2004 and 2005, with some residents reporting sewer flooding up to six times in recent years.
To date in this region, customers in over 1,700 basement properties have been assessed to flood due to the overloaded sewer system.
What's causing the sewer flooding
Loss of natural drainage
A Thames Water study revealed that impermeable land in the Counters Creek catchment had increased by about 17 per cent since 1971, far higher than had been expected.
One example of this is that many front gardens have been paved over to make way for parking spaces. This significantly increases the risk of flooding when it rains heavily, as more rain water runs into our sewers, rather than soaking into the ground.
The wider catchment
A study of drainage in the area concluded that the Counters Creek catchment receives storm flows from as far away as Brent and Camden.
This can mean our local sewers in the Counters Creek area are filled up quickly and have insufficient capacity to deal with storm flows in the local area.
Hammersmith & Fulham and Kensington & Chelsea have a high proportion of basement properties.
Properties below ground are more likely to flood if they are not protected, because their floor levels are closer to the sewer levels.