Dynamic vegetation Roughness in the riparian zone
Dynamic vegetation Roughness in the riparian zone
复制标题
河岸带动态植被粗糙度
DOI：
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发表时间：
2013
期刊：
影响因子：
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通讯作者：
Tyler Gillihan
中科院分区：
文献类型：
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作者：
Tyler Gillihan
河漫滩的植被对明渠水系的水力学起着重要的作用。虽然植被有利于河流系统的生物生产力，但由于河道粗糙度增加，也会增加洪水风险。传统的水流水力学预测方法涉及应用恒定的粗糙度值，而忽略了由于水流特性和植被参数的变化而引起的粗糙度变化。本研究的目的是开发和演示技术，水力模型的明渠河流系统，同时考虑到动态粗糙度，由于植被。对SRH-2D模型进行了改进，使其能够在模拟系统水力学的同时，利用实测植被参数计算动态曼宁n值（简称有效n（ne）值）。两种基于Järvelä（2004）和Baptist等人（2007）工作的方法被应用到SRH-2D中进行粗糙度计算。实地和建模工作集中在加州弗雷斯诺附近的圣华金河沿着的一段恢复区。这两种方法在四个不同的渠道流量：31.2，70.8，113.3，和212.4立方米/秒。敏感性分析也进行了两种方法在113.3米3 /秒的参数的不确定性。宽范围的计算ne值表明，粗糙度是依赖于
Vegetation in the floodplain plays an important role in dictating the hydraulics of an open channel river system. While vegetation is beneficial to the biological productivity of the river system, it can also increase flood risk due to increased channel roughness. Traditional means of predicting flow hydraulics involve applying a constant roughness value, while neglecting change in roughness due to flow characteristics and variation of vegetation parameters. The objective of this research was to develop and demonstrate techniques to hydraulically model an open channel river system while taking into account dynamic roughness due to vegetation. The Sedimentation and River Hydraulics in Two-Dimensions (SRH-2D) model was enhanced to use measured vegetation parameters to calculate dynamic Manning’s n values, referred to as effective n (ne) values, while simulating the hydraulics of the system. Two approaches based on work by Järvelä (2004) and Baptist et al. (2007) were implemented into SRH-2D for roughness computations. Field and modeling work focused on a section of a restoration area along the San Joaquin River near Fresno, California. Both approaches were modeled at four different channel discharges: 31.2, 70.8, 113.3, and 212.4 m 3 /s. A sensitivity analysis was also performed for both approaches at 113.3 m 3 /s for parameters of uncertainty. A wide range of calculated ne values showed that roughness is dependent