Oxford's major floods are a result, not of water falling onto the immediate area, but of water which has fallen as far away as the Cotswolds coming down the valley of the River Thames. Severe flooding occurs in the plain to the west of Oxford. There is a marked geological narrowing of the Thames valley immediately south of Oxford city, around the old Abingdon Road red-brick bridge over the railway at Redbridge in South Oxford /Kennington. The natural narrowing has been made far worse by the building of the railway, roads and buildings, and by landfill. In some cases these seem to have been done with little or no regard for the possible effects on flooding, and lack of proper maintenance over many years has made things even worse. Further up, the Botley Road is a particular problem. It is a causeway across the floodplain from the City to Botley and Cumnor beyond. There is not enough capacity to carry water under it, or immediately to the south of it, so it acts as a dam. This leads to flooding.

 

A major project by the EA, to provide high level flood protection for Oxford, the Oxford Flood Risk Management Strategy, is unlikely ever to be implemented.