Century-scale channel change in central Arizona-Phoenix: photographs of selected reaches of the Salt River in different years

Study how the geomorphology of the Salt River channel has changed over the last
100 years and how factors such as the damming of the Salt and Verde Rivers and
gravel mining operations have contributed to these changes. For more than 1,000 years there has been a city on the banks of the Salt and Gila
Rivers in the vicinity of what is now Phoenix. The course of natural processes as
embodied by the river have interacted with the course of human events as evidenced
by the city, each exerting influence on the other. The myriad of tangled connections
between the natural and social systems has inevitably altered each of them, so that
understanding of one without understanding of the other is incomplete. Within the
last 100 years, intensive technological development of the river resources, its
space, water, materials, and biotic complements, has radically altered the natural
processes and forms of the river. At the same time, the river has influenced
development of the city, sometimes as a resource such as recreational space, and
sometimes as a hazard such as flooding. This constantly changing fluvial system,
integrating natural and artificial influences, is the foundation for the primary
riparian ecosystems of the region. The research questions of this project are: (1) What has been the nature of change
in the geomorphic/riparian system, and how have human and natural factors controlled
the distribution and intensity of the change over the past century? (2) Why does the
river have its present geomorphic/riparian configuration, and how stable is that
arrangement from geomorphic, hydrologic, and geographic perspectives? and (3) How
does the river respond to ongoing changes in the spatial arrangement of human
activities and attending technological impacts? This project promises improved understanding of the dynamics of dryland rivers,
especially how and why they change under the influence of urban development. The
research also promises to provide an integrating factor in the CAP LTER effort,
because the river integrates the influences of hydrologic, geomorphic, biotic, and
human technological systems. The research will provide a repeatable quantitative
approach to assessing the changes in the river and as it continues its
millennium-long connection between natural and social systems.

本研究旨在探讨过去百年间盐河（Salt River）河道地貌学（channel geomorphology）的演变历程，以及盐河与维德河（Verde River）筑坝、砂石开采活动等因素对河道变化的驱动作用。

在如今菲尼克斯（Phoenix）周边区域，盐河与希拉河（Gila River）沿岸已有人类聚居城市超过千年。以河流为载体的自然过程与城市所代表的人类活动进程相互交织、彼此影响。自然系统与社会系统之间错综交织的多重联系，必然会对二者各自的状态产生改变，因此仅单一维度的认知必然是不完整的。在过去百年间，人类对河流资源（包括其空间、水体、沉积物及生物群落）的高强度开发利用，已从根本上改变了河流的自然过程与形态。与此同时，河流也对城市发展产生着双向影响：既可作为休闲空间等资源供给，也可能以洪水灾害的形式构成威胁。这种融合自然与人工扰动的动态河流系统，是该区域核心河岸生态系统（riparian ecosystem）的基础载体。

本项目的研究问题如下：（1）过去一个世纪以来，地貌/河岸（geomorphic/riparian）系统的变化特征如何？人类与自然因素如何调控了该变化的空间分布与强度？（2）当前河流的地貌/河岸格局形成的原因是什么？从地貌学、水文学与地理学视角来看，该格局的稳定性如何？（3）人类活动空间布局及其伴随的技术扰动持续发生变化，河流对此将作出何种响应？

本项目旨在深化对干旱区河流（dryland river）动态变化的认知，尤其是其在城市开发影响下的变化机制与驱动因素。同时，本研究可为CAP LTER计划提供整合性研究框架——因该河流整合了水文、地貌、生物及人类技术系统的多重扰动。本研究将提供一套可重复的定量方法，用于评估河流的动态变化，并助力其延续千年来自然与社会系统之间的互动联系。