Development of an initial screening tool for the relative assessment of risk to potable water supplies due to large-scale urban development

The concentration of people in both megacities and smaller cities increases the vulnerability of the population to natural and manmade hazards. The quality of life for many residents of megacities can be greatly reduced because of water and soil contamination, environmental health problems, and limited green-space. There is a need for strategic planning and development tools that can assess the potential risk. This research project is focusing on providing planners with a method for evaluating the potential contamination risk to surface and groundwater created by new developments. The resulting tool will allow the ranking of various proposed development scenarios on the basis of a semi-quantitative assessment of contamination risk. It will also provide planners with information on the type, spatial distribution, and hazard, associated with potential contamination sources within their area. Contaminants arising from urban land uses may be point-source, linear (e.g. fuel pipelines, collectors), or at such a small-scale and so widespread that they are in effect diffuse sources (soakaways, older sewer systems). Faced not only with a plethora of activities and associated contamination but also diverse modes of occurrence, concentration ranges, contaminant behaviours and levels of persistence; regulators, municipal/regional planners and insurance organisations are increasingly looking to the assessment of risk to provide a pragmatic but not over-precautionary approach to urban development that needs to go far beyond the mechanistic identification of hazard factors. The Initial Screening Tool (IST) will collate and interrogate a range of geoscientific information such as 2D and 3D geological maps and models, past land use, historic maps, geochemical and geophysical data, water abstraction boreholes, groundwater level maps and site investigation reports onto a single user platform. The Tool will use screening level information to rank alternative development scenarios on the basis of the risk of linkage between contaminant sources, pathways and receptors. This input to the decision-making process will promote sustainable land development as an integral part of ?best practice urban design.