Optimization of the Two-Dimensional Hydrodynamic Model for the Ottawa River

准确和快速地估计河流当前的流场对于合理规划防洪、环境影响评估、应对与危险物质泄漏有关的环境紧急情况、资源管理和评估气候变化的社会经济影响至关重要。随着计算技术的进步，河流水力学数值模拟变得可行和普遍。然而，大多数现有的模型和模型工作仍然停留在学术水平和/或为实现非常具体的工程项目而开发的，例如水利工程结构的设计和泛滥平原的评估。非常有限的河流建模项目已经升级到业务水平，不断预测高质量的水流，结合环境条件的持续波动来应对业务需要。而当河流模型投入运行时，大多是一维的，用来评估水位。这项研究的主要目的是设计和优化渥太华河的二维水动力模型，以供业务应用，以支持该水系统的应急响应。 具体地说，该项目的第一个目标是开发一个从Chat Falls到Carillon的渥太华河流的二维水动力模型，以预测具有高空间分辨率的水平流场，以捕捉复杂的流动模式，如流动再循环和扩散。第二个目标是在不降低预报精度的情况下，综合分析局部网格分辨率对计算水位、流速、二次流等的影响，优化计算成本。 开发的模型将经过仔细的校准，并根据观测数据进行验证。模型的计算网格将得到高度优化，这种优化可以在不明显影响模型精度的情况下显著提高模型的效率。这项研究包括在ArcGIS的帮助下准备基于高程、开放街道和导航地图的数字高程模型，确定计算区域，使用BlueKenue中的不同设置参数生成各种网格，进行网格敏感性分析并使用TELEMAC进行模拟，校准模型，并准备一份技术报告来描述研究及其结果。

An accurate and fast estimation of the current flow fields in rivers is crucial for sound planning of flooding prevention, environmental impact assessment, responding to environmental emergencies related to spill of hazardous substances, resource management, and assessment socio-economical impacts of climate change. With the advance in computing techniques, numerical modeling of river hydraulics has become feasible and popular. However, most of the existing models and modelling works that were remained at the academic level and/or were developed to achieve very specific engineering projects, such as the design of hydrotechnical structures and assessment of floodplain. Very limited river modelling projects have been escalated to the operational level in which high-quality current are being predicted continuously integrating the continuous fluctuations in the environmental conditions to respond to operational needs. And when river models are run operationally, there mostly one dimensional and used to assess water level. This research aims primarily to design and optimize a two-dimensional hydrodynamic model for the Ottawa River for operational applications to support emergency response in that water system. Specifically, the first objective of this project is the develop a two-dimensional hydrodynamic model for the Ottawa River from Chat Falls to Carillon to predict horizontal current field with high special resolution to capture complex flow patterns, such as flow recirculation and dispersion. The second objective is to optimize the computational costs without lowering the prediction accuracy, based on a comprehensive analysis of the influence of local mesh resolution on the calculated water level, current velocity, and secondary flows, etc. The developed model will be carefully calibrated and validated against observational data. The computational mesh of the developed model will be highly optimized and this optimization can significantly increase the model efficiency without obviously impacting the model accuracy. This research includes preparing a digital elevation model based on height, Open Street, and navigational maps with the assistance of ArcGIS, determining the computational area, generating various meshes using different setting parameters in BlueKenue, conducting mesh sensitivity analyses and performing simulations using TELEMAC, calibrating the models, and preparing a technical report to describe the study and its findings.