That explains it! Nobody studies hydrology in its own right, and so this limp appendage of other scientific pursuits has been ignored. Pity - because hydrologic science and simple quantifiable land use changes can explain increased runoff and increased urban flood damages in Ontario municipalities. Why is it ignored? Because hydrology is just the foreplay to other things like dynamic hydraulic simulations and then infrastructure construction. Everybody is always stampeding to the Priestman slot, frothing over pressure head - hydraulic hussies! A veritable orgy of climate simulators, and media stimulators, rages on while hydrologists are left alone :(
So we need some "tantric hydrology" people. Slow and savoured and reflected upon. Maybe if Sting was an engineering professor instead of an english teacher he could have promoted it, and enlightened the masses to the joy of runoff coefficients. Alas, he wasn't and it is so up to CityFloodMap.com to spell it out - how increased urbanization has affected hydrologic responses in Ontario cities and magnified runoff potential, flood damages, and insurance losses.
Just open your peepers and gaze upon these Ontario urban area land use maps, and see how the limits of urban areas have increased over thirty years or so from 1966 to the late 1990's. It can be dramatic. For some catchments, the increase in urban land coverage can be an order of magnitude.
Sure, some of these areas developed between 1966 and 2000 have stormwater management controls up to a point. But it is commonly accepted that the on-site local stormwater controls do not completely address cumulative volumetric runoff impacts at larger scales. And the controls are finite - not controlling the rarest storms that drainage infrastructure could see in its design life. So expanded urban areas can drive downstream flood risk. Yes, every catchment is different and maybe no property is at risk downstream of some urbanized area (i.e., dedicated drainage easements and wide regulated flood plains have maintained a wide major flow path) - but in may cities the overland flow path has not been mapped managed or preserved, so increased runoff and flood risk can result.