Uncertainty methods for groundwater flow and transport modelling

地下水流和输运建模的不确定性方法

• 批准号: 3754-2006
• 负责人: Sykes, Jonathan
• 金额: $ 1.82万
• 依托单位: University of Waterloo
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2006
• 资助国家: 加拿大
• 起止时间: 2006-01-01 至 2007-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=332081
• 关键词: Uncertainty; methods; groundwater; flow; transport

Uncertainty analyses of groundwater systems are commonly used to derive the moments of the system dependent variables as a function of the uncertainty in the system parameters; usually only the first two moments are estimated.  For many problems however, it is not the first and second moment that are important but rather it is estimates at the tails of the PDF that are critical.  The classical problem of the first arrival of a contaminant at a biosphere point or receptor is one such example.  While analysts may estimate the full distribution of the concentration, the public, regulators and courts are often only concerned with the earliest possible arrival of a contaminant to a groundwater well.  Economic decisions often are made on these low-probability occurrences.  The difficulty for the analyst then is the robustness of the concentration PDF tails.  Important factors in the estimation of the probability at the tail of the distribution include parameter uncertainty, correlation, and the method used to determine the uncertainty.    The objective of the proposed research program is to develop and implement uncertainty methods that can be applied to detailed complex groundwater models.  The methods will be applied in the risk and safety assessment of deep geologic repositories for nuclear waste.  The methods will also be applicable for the assessment of groundwater protection zones and the forensic simulation of contaminant arrival at a biosphere point in either fractured or porous media.  For the forensic modeling, the case studies that will be explored include: the analysis of the arrival of a contaminant at a municipal well field that supplies water to a community with a statistically significant childhood cancer cluster; and the allocation of a bankruptcy trust to individuals with various health impacts (cancers) as a function of contaminant exposure concentration and duration.

地下水系统的不确定性分析通常用于导出系统因变量的矩作为系统参数不确定性的函数;通常只估计前两个矩。然而对于许多问题，重要的不是一阶和二阶矩，而是PDF尾部的估计是关键的。生物圈点或受体的污染物就是这样一个例子。虽然分析人员可以估计浓度的全部分布，但公众，监管机构和法院通常只关心污染物尽早到达地下水井的可能性。经济决策通常是在这些低-概率发生。分析师的困难是浓度PDF尾部的稳健性。估计分布尾部概率的重要因素包括参数不确定性，相关性，以及用于确定不确定度的方法。 该研究计划的目标是开发和实施可应用于详细复杂地下水模型的不确定性方法。该方法将应用于核废料深层地质处置库的风险和安全评估。该方法也将适用于地下水保护区的评估和污染物到达断裂或多孔生物圈点的法医模拟。对于法医建模，将探讨的案例研究包括：分析污染物到达市政井场，该井场向具有统计学显著儿童癌症集群的社区供水;以及将破产信托分配给具有各种健康影响（癌症）的个人，作为污染物暴露浓度和持续时间的函数。