Surface water flooding : sustainable drainage to the ground

摘要

During the exceptional rainfall events of summer 2007, floods inundated 7,300 businesses and 48,000 homes across the UK (PITT Review) with estimated costs of £3.2 billion. A review of the causes and consequences of these events (PITT review) identified that extreme rainfall and overwhelmed drainage systems led to surface water being a primary cause of flooding. This type of flooding is particularly problematic in urban areas where rapid run-off from impermeable surfaces (roofs, pavements), exceeds the drainage capacity of that area leading to flooding in locations that are difficult to predict. The impacts are not restricted to water volume; the quality of water in receiving watercourses can also be compromised by pollutants entrained in run-off water and sewage contamination derived from Combined Sewer Overflow surcharging.