Brief Report upon the Strategic Flood Risk Assessment (SFRA)

The Report was produced by Halcrow Group Limited for Dacorum Borough Council, St. Albans City & District Council, Three Rivers District Council, Watford Borough Council. Paul Wilkinson of Halcrow had intended to attend the DEF meeting of 17th January, 2008 but has sent his apologies. This Foreword from the main Report is circulated for information. The full Report will be available on the DBC Web Site

The purpose of this Strategic Flood Risk Assessment (SFRA) study is to assess and map all forms of flood risk from groundwater, surface water, sewer and river sources, taking into account future climate change predictions, and use this as an evidence base to locate future development primarily in low flood risk areas. The outputs from the SFRA will help the Four Council’s to prepare sustainable policies for the long-term management of flood risk and improve existing emergency planning procedures.

Issues of emergency planning, disaster recovery and climate change have been topping the news headlines this summer as a result of the devastating flooding which occurred in the Midlands, North East and Thames Region, following record levels of rainfall (worst affected areas were Sheffield, Hull, Gloucestershire and Oxfordshire and Berkshire).

By comparison, the level of flood risk is lower within the study area, particularly along the chalk tributaries (Rivers Ver, Gade, Bulbourne and Chess). Here, the catchment topography is such that river flooding will only affect a relatively narrow and well-defined corridor, as opposed to the expansive and low-lying floodplains of Hull, for example. The main issues relate to the capacity of surface water and sewer drains, which can result in localised flooding following heavy rainfall. As experienced recently on the 20th July 2007, this localised flooding can cause disruption to traffic as well as damage to property.

The main pockets of higher flood risk (from rivers) tend to be localised. They are located along the Upper River Lee through Harpenden and Wheathampstead and the Upper River Colne through Colney Heath, London Colney and Watford. Within and around these areas it is important that effective flood risk management policies are implemented and that future development does not contribute to increased flood risk. This will be achieved by implementing the recommendations provided in the SFRA.