Sustainable development and flood risk – reducing uncertainty (bristol city re-development case study)

Abstract

Development and Flood Risk has become a topical subject for debate at national, regional and local level by politicians, planners, regulators and those with commercial and legal interests. Current UK planning policy guidance seeks to manage and reduce the impact of flooding by applying a precautionary approach to the land-use planning process and further to take account of climate change. As part of any development proposal there is the need to prepare estimates of flood depth, extent and frequency. In making such predictions much reliance is placed on the application of computational modelling often in circumstances where these is little or no supporting hydrometric data to provide corroboration. The paper illustrates the practical measures that have been taken to reduce the uncertainty associated with an established flood risk impacting an urban redevelopment proposal within a major English conurbation. The strategic collation and enhancement of key datasets, including topographical, hydrological and asset information is presented. Focusing on a significant investment in hydrometric measurement and the creation of a fully hydrodynamic two-dimensional hydraulic model the paper demonstrates the requirement for high quality datasets and the use of appropriate techniques in circumstances where model water level predictions are sensitive to small changes in key parameters. In conclusion consideration is given to how the planning process can encourage the appropriate fiscal and resource investment needed to reduce uncertainty in flood risk assessments.