Vertically Meandering Mountain Streams

山溪是世界水和沉积物供应的主要来源，是流入低地河流和较大水体的主要水库。 这些山间溪流的特点是台阶和水池占优势，呈现出引人注目的阶梯状纵向轮廓，多年来一直吸引着科学家。 最近，频谱分析的应用已经确定了周期性的步骤和池的发生，从而表明流量和通道形态之间的相互调整，并在垂直方向上的蜿蜒的类比。 虽然这一发现扩展了从下游渠道的水池和浅滩到流域源头地区的阶梯水池的垂直弯曲的基本重要概念，但阶梯水池河床的振荡并没有受到与水池和浅滩以及弯曲河流相同水平的分析。 本研究将结合野外、实验室和统计学方法，建立一个定量模型来描述、预测和解释韵律性阶池形态，并充分确立其作为山溪垂直弯曲的表达的意义。 时间序列分析技术将被应用到一个大型数据库的步骤池流从世界各地开发一个模型，可以描述和预测的节奏序列。 步骤池渠道在圣莫尼卡山脉的加州也将进行调查，并在1991年建成的配置文件进行比较，以评估在十年的时间尺度的周期性变化。 水槽实验将进一步提供具体的假设，周期性的步骤池序列最大限度地减少流功率在山区河流系统，从而连接的节奏形式的能量消耗的原则测试。 总的来说，这些成果预计将证明，可预测的，定期的步骤池山区河床的发展和保存在广泛的环境，以保持平衡的通道几何形状下的高能量conditions.The综合治疗在这项研究中进行的，预计将提升我们的理解，垂直振荡的山溪走向的riffle-pool和水平曲流几十年来众所周知的。 开发一个通用的预测模型的韵律步骤池序列将深入了解在山区溪流的基本过程。 将重复的阶梯-水池形式与能量消耗原理联系起来，将增强我们对河流行为的总体理解。 加强了解的垂直模式，在步骤池流将有助于稳定的通道设计和流恢复使用步骤池，一种做法，这是越来越多的山区和城市环境。 对陡峭的山溪进行有效的设计和管理将减轻洪水危害，保护下游社区的财产和生计。 由于山溪是许多敏感水生物种的重要栖息地，本研究的结果将有进一步的生态管理的重要意义。

Mountain streams are major sources of the world's water and sediment supply, serving as the primary reservoirs feeding into lowland rivers and larger water bodies. These mountain streams, which are characterized by a preponderance of steps and pools, exhibit a striking, staircase-like longitudinal profile that has intrigued scientists for many years. Recently, the application of spectral analysis has identified periodicities in the occurrence of steps and pools, thereby suggesting a mutual adjustment between flow and channel morphology, and an analogy to meandering in the vertical dimension. Although this finding extends the fundamentally important concept of vertical meandering from pools and riffles in downstream channels to step-pools in headwater areas of river basins, the oscillations in the step-pool streambed have not been subjected to the same level of analysis as those in pools and riffles and the meandering river. Using a combination of field, laboratory, and statistical methods, this research will develop a quantitative model to describe, predict, and explain the rhythmic step-pool morphology, and to fully establish its significance as an expression of vertical meandering in mountain streams. Time-series analytic techniques will be applied to a large database of step-pool streams from around the world to develop a model that can describe and predict the rhythmic sequences. Step-pool channels in the Santa Monica Mountains of California will also be surveyed and compared to profiles constructed in 1991 to assess change in the periodic character over decadal timescales. Flume experiments will further provide specific tests for the hypothesis that periodic step-pool sequences minimize stream power in the mountain river system, thus linking the rhythmic form to principles of energy expenditure. Collectively, these outcomes are expected to demonstrate that predictable, periodic step-pool mountain streambeds develop and are preserved in a wide range of environments to maintain equilibrium channel geometries under high energy conditions.The comprehensive treatment undertaken in this study is expected to elevate our understanding of the vertical oscillations in mountain streams toward that of riffle-pools and horizontal meandering well known for decades. Developing a general predictive model for rhythmic step-pool sequences will give insight into the underlying processes operating in mountain streams. Linking the repetitive step-pool form to principles of energy expenditure will enhance our understanding of river behavior in general. Enhanced understanding of the vertical patterns in step-pool streams will assist stable channel design and stream restoration using step-pools, a practice that is increasing in mountain and urban settings. Effective design and management of steep mountain streams will mitigate flood hazards and protect property and livelihood in downstream communities. Because mountain streams are important habitats for many sensitive aquatic species, results of this study will have further important implications for ecological management.