What is Local Overland Flooding?
Local Overland Flooding results from runoff which travels as sheet flow over grassed and paved surfaces. The Overland Flooding Investigation caters for two levels of Local Overland Flooding, Local Drainage and Major Drainage, which are distinguished by the depths of flooding and the potential danger to personal safety and damage to property. At the lower end of the scale, Local Drainage problems may involve shallow depths of overland flooding (up to 300 mm deep) with generally little danger to personal safety. Problems could typically arise because of deficiencies in building practice where floor levels are too close to finished ground levels. At the upper end of the scale, Local Overland Flooding may involve the flow paths of original drainage lines, whether natural or altered by urban development, and may be categorised as Major Drainage. Depths of flooding are generally in excess of 300 mm and conditions may result in danger to personal safety and damage to property (premises and ve
