Integrated watershed modeling techniques have been applied in recent years to examine surface and subsurface interactions. Model performance is often evaluated by best fit of the hydrograph, which alone cannot explicitly explain whole catchment dynamics. To overcome this problem, this study incorporated multiple tracers (³H, ⁸⁵Kr, and groundwater temperature) into a physically-based fully distributed modeling framework for characterizing regional-scale hydrological processes in Kumamoto, southern Japan. First, a simulation performed by a hydrometrically calibrated model showed satisfactory performance for river discharge and groundwater level. However, this model showed poor fitting for isotopic composition and temperature due to the structural uncertainty of the model. A new model was established reflecting recent deep bore log data and incorporating tracer data showed acceptable accuracy for hydrographs and tracers. Thus, more reliable estimates of groundwater storage, groundwater age and water flow paths were depicted over the regional catchment. Comparisons between the two models indicate that the model structure of an area with an uncertain lower boundary can be addressed by incorporating multiple tracer data. Tracer-aided models could be applied for a holistic understanding of contaminant transport dynamics besides flow simulation.

近年来，综合流域建模技术已应用于检查地表和地下相互作用。模型性能通常通过水文过程线的最佳拟合来评估，仅凭这一点无法明确解释整个流域动态。为了克服这个问题，本研究结合了多种示踪剂 ( ³ H, ⁸⁵Kr 和地下水温度）转换为基于物理的完全分布式建模框架，用于表征日本南部熊本的区域尺度水文过程。首先，由水文校准模型执行的模拟显示了河流流量和地下水位的令人满意的性能。然而，由于模型的结构不确定性，该模型对同位素组成和温度的拟合较差。建立了一个新模型，反映了最近的深孔测井数据，并结合了示踪数据，显示了水道图和示踪剂的可接受精度。因此，在区域集水区描绘了对地下水储存、地下水年龄和水流路径的更可靠估计。两个模型之间的比较表明，下边界不确定区域的模型结构可以通过合并多个示踪数据来解决。除流动模拟外，示踪剂辅助模型还可用于全面了解污染物传输动力学。