Risk analysis can be qualitative or quantitative. The analysis often seeks qualitative and quantitative risk assessment pdf describe the consequences in numerical units such as dollars, time, or lives lost.
How likely is it that it will happen? If it does happen, what are the consequences? These game-theoretic techniques may be probabilistic or deterministic. Qualitative risk assessment, in absence of precise values for likelihood and consequences, assigns relative and broad classifications to the likelihood and consequences for each risk and does not build a precise mathematical model of risk as suggested by PRA. Qualitative, pseudo-quantitative, or scoring methods have been heavily criticized because they do not obey mathematical rules and may not correctly rank risks. They have the appearance of being rigorous but provide a false sense of security to those organizations that rely on them to manage risks.
Undertaking a full quantitative approach provides a more rigorous analysis and a better foundation for making good risk management decisions than relying on pseudo-quantitative methods. Garrick, ‘On the quantitative definition of risk’, Risk Analysis, Vol. What’s Wrong with Risk Matrices? This page was last edited on 3 December 2017, at 22:58. Groundwater risk assessment for your environmental permit – GOV. How to carry out a groundwater risk assessment as part of an application for an environmental permit.
How to carry out a groundwater risk assessment as part of an application for an environmental permit. You may need to carry out a groundwater risk assessment to carry out activities that could directly or indirectly pollute groundwater. You need to develop a conceptual model. This will form the basis for your risk assessments and will help you successfully evaluate environmental risks. You’ll need to develop and refine your model iteratively within each level of risk assessment you carry out.
Conceptual models for groundwater protection describe important hydraulic, hydro-chemical and biological processes that are at work in the soil, the unsaturated zone and the groundwater itself. Your model should describe potential environmental impacts associated with the site, and any uncertainties in how the activity will interact with the hydrogeological setting. As pollutants often travel through the unsaturated zone to reach groundwater, you should include the processes acting on pollutants in the unsaturated zone where appropriate. If you identify the potential for a direct discharge in the conceptual model and risk screening stage, then you must carry out a risk assessment that is correspondingly more detailed. The desk study examines the environmental setting and any potential contamination from past activities on or next to the site where the activity is proposed.
Collect together all available and relevant information to characterise the site and its surroundings from literature, public registers and site reconnaissance. The search radius for these will depend on the activity, but typically should be about 1 km radius from your discharge area. Where the geology and hydrogeology of the area is layered, you need to ascertain the construction details of wells and springs to check whether the abstraction is from a shallow vulnerable layer or deeper, confined and protected layer. The desk study will identify any uncertainties related to both the activity and the site’s hydrogeological setting, and how these might interact. The nature and scale of these uncertainties will determine your need for site investigations and guide the development of any site investigation programme. Use this information to form an initial site conceptual model.
This is an iterative process and as you get further site-specific information, you’ll need to review and refine your model. You may need to update your conceptual understanding of the activity and its potential impact on the environment accordingly. You need to research and model both hazardous substances and non-hazardous pollutants that are likely to be present depending on the type of activity being proposed. For example, a landfill source will need to include a range of hazardous substances and non-hazardous pollutants. The risk assessment for land spreading of domestic treated sewage effluent may only need to include a limited range of non-hazardous pollutants.