this is a picture of severe flooding in glasgo, scotland in 2002. you can see the contribution that the drainage system is making here. you can see the water streaming out of the drainage system on to the surface. the flood event showed the urban system was full to capacity approximately 20 minutes into the storm. it only conveyed something like 20 percent of the flood water. the storm lasted for about 4 hours. 80 percent of the flood flow was conveyed on the surface. this is a good example, this is a hundred year event. this is a good example of the sorts of extreme events that we're going to see much more frequently in our urban areas. our urban drainage systems already are incapable of conveying most of the flood water that arises from intense storms and they are likely to be even less likely able to carry that in the future. so how are we going to cope with that aspect? what we're starting it look at in the uk is how do we design our urban areas better so these flood flows can be managed above ground, recognizing that major above ground system i