CJL
Member
London is a strange one as it has a combined sewer system rather than the surface water and foul systems. In a combined system ALL the water (from toilets and sinks -normally called foul water, is allowed to mix with rain water from the roof and roads - normally called surface water) goes into the sewer. It is an unimaginable quantity, made worse by lots of people concreting over their drives, building and fields. This means the rain water lands in London and very quickly gets into the sewer and to the sewage works when normally it would soak into gardens and go into the groundwater. At the sewage works they are inundated with a mixture of foul sewage and surface water that needs to be treated. The only good thing is that the sewage is relatively dilute compare to non rainy days. The Victorian solution was to pump it into the river when the system is overwhelmed which is what Thames Water are stuck with. They have built extra capacity to try and buffer these high flows but the reality is a proper separate sewer network with foul and surface water is needed to solve the problem buts it would require billions of pounds to dig up the sewers to sort it. The super sewer is kinda of a halfway house solution, catching the overspill from the sewage works before it enters the Thames at Isleworth Ait.
If Thames Water didn't discharge to the River in storm events it would just cause sewage flooding and back up the pipes which is unthinkable for people. The typical out if sight, out of mind attitude that society has means that pumping it into rivers is OK and the lesser of the two evils. The super sewer is expensive and disruptive but I don't see another option which protects boats and the environment anywhere near as well.
Sorry for going on so long but thats my take on it.
CJL
