Abstract To bypass the problem of numerical instability in conducting the channel routing system, the application of an impulse response function based on the linearization of Saint Venant equations has been an alternative for predicting streamflow discharge. However, the distribution type of the impulse response function proposed by Dooge et al. (1987a) is restricted during a flood, so this approach cannot adequately describe flow response in practical applications. In considering that the flow response in a natural channel is usually influenced by the shape of the cross-section, the terrain of channel bed and the discharge of the moving flood, this study focuses on improving the original unit impulse function by conducting two aspects of analysis: (1) the distribution of unit impulse response function was changed with time by adjusting the reference parameters according to the inflow condition and the hydraulic variables; (2) the outcome of this modified linear approach was thoroughly examined by comparing the simulated results with that adopting the original linear channel method and the numerical scheme based on the nonlinear Saint Venant equations. Moreover, for achieving the simulation of a whole river basin, a complete executing procedure was provided to explain the connection between the upstream inflows, lateral flows, and the linear channel response of each channel reach. A series of tests showed that the proposed method can produce approximated hydrographs in comparison with numerical simulation results owing to the flexibility of the impulse response function although the linear channel routing adopts simplified mathematical operations. A case study of a natural river basin also demonstrated the applicability of the modified channel response system.

中文翻译：

---

考虑入流条件和水力特性的河道水文响应函数

摘要 为了绕过通道路由系统中数值不稳定性的问题，基于圣维南方程线性化的脉冲响应函数的应用已成为预测河流流量的替代方法。然而，Dooge 等人提出的脉冲响应函数的分布类型。(1987a) 在洪水期间受到限制，因此这种方法不能充分描述实际应用中的流动响应。考虑到自然河道中的水流响应通常受断面形状、河床地形和移动洪水流量的影响，本研究重点通过两个方面来改进原始单位冲激函数。分析：(1)根据入流条件和水力变量调整参考参数，使单位脉冲响应函数的分布随时间变化；(2) 通过将模拟结果与采用原始线性通道方法和基于非线性 Saint Venant 方程的数值方案的模拟结果进行比较，彻底检查了这种改进的线性方法的结果。此外，为了实现对整个流域的模拟，提供了一个完整的执行程序来解释上游进水、侧流和每个河段的线性河道响应之间的联系。一系列测试表明，尽管线性通道路由采用简化的数学运算，但由于脉冲响应函数的灵活性，所提出的方法可以产生与数值模拟结果相比的近似水位线。一个天然河流流域的案例研究也证明了修改后的河道响应系统的适用性。