Development of an Evolutionary Flow Path Model of Water and Solutes

9406436 McDonnell水文流动路径的知识对于理解径流的产生和污染物的传输，以及对水文通量和地球化学通量之间的联系进行建模至关重要。然而，在水文调查中，模型和实地研究没有很好地联系起来。此外，将这种现场观测引入模型的尝试不可避免地面临着额外数据的价值和考虑数据所需参数的可辨识性之间的妥协。对径流径流路径的新研究表明，需要空间分布的模型来捕捉关键的水文和地球化学过程。这项工作将开发一个新的协同联系的水文/地球化学模型，说明：(1)水如何沿不同的流动路径以化学和同位素方式演化，(2)特定的流动路径产生与水的地形位置和水文历史有关的独特“特征”。不确定度分析将用于评估模型参数中的不确定性。我们的目标是：(I)开发一个水文地球化学模型，在该模型中，河流化学和径流路径的动态可以与野外工作相关；(Ii)评估模型结构/参数的不确定性，并确定减少这种不确定性的野外工作策略；(Iii)在野外进行空间分布的测量，以验证土壤湿度、地下水位高度、同位素和溶质浓度的空间分布估计；(Iv)通过利用汇水区的物理特征和响应，检查对径流路径的地球化学/同位素演化的控制。(V)将新模型作为检验具体径流假设和进行总体混合的工具。本研究是一项创新性的尝试：(I)将受溶质同位素和地球化学数据约束的演化反应路径模型与地形驱动的山坡尺度水文模型联系起来；(Ii)以野外活动和模型不确定性评估的相互作用为约束的形式，开发了一种新型的水文地球化学模型。这项工作将使完全分布式模型更容易应用于其他研究领域。

9406436 McDonnell The knowledge of the hydrologic flowpaths is critical to understanding runoff of generation and the transport of pollutants on to modeling the linkages between hydrologic flux and geochemical flux. However, models and field studies are not well linked in hydrological investigations. Furthermore, attempts to introduce such field observations into models have faced the inevitable compromise between the value of additional data and the identifiability of parameters required to take account of the data. New research on runoff flowpaths has shown that spatially- distributed models are required to capture the key hydrological and geochemical processes. This work will develop a new synergistically linked hydrologic/geochemical model of how: (1) waters evolve chemically and isotopically along the different flowpaths and (2) specific flowpaths produce distinctive "signatures" related to the topographic position and hydrologic history of the water. Uncertainty analysis will be used to assess uncertainty in the model parameters. Our objectives are: (i) to develop a hydrogeochemical model within which the dynamics of stream chemistry and flowpaths can be related to fieldwork, (ii) to assess model structure/parameter uncertainties and identify fieldwork strategies to reduce such uncertainties, (iii) to make spatially-distributed measurements in the field to validate spatially-distributed estimates of soil moisture, water table elevations, isotope and solute concentrations, (iv) to examine the controls on geochemical/isotopic evolution along flowpaths by using physical characteristics and responses of the catchment, and (v) to use the new model as a tool for testing specific hypotheses on flowpaths and mixing overall this study represents an innovative attempt (i) to link a evolutionary reaction-path model constrained by both solute isotope and geochemical data within a topographically-driven hydrologic model at the hillslope scale and (ii) to de velop a new type of hydrogeochemical model in a form constrained by the interaction of the field campaign and the assessment of model uncertainty. The work would make it easier to apply fully distributed models in other study areas.