Type and timing of stream flow changes in urbanizing watersheds in the Eastern U.S.
Type and timing of stream flow changes in urbanizing watersheds in the Eastern U.S.
复制标题
美国东部城市化流域河流流量变化的类型和时间
DOI：
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发表时间：
2015
期刊：
影响因子：
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通讯作者：
M. Palta
中科院分区：
文献类型：
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作者：
K. Hopkins;N. Morse;D. Bain;N. Bettez;N. Grimm;J. Morse;M. Palta
将水文变化的类型和时间与城市增长模式联系起来对于确定驱动城市水生生态系统衰退的潜在机制至关重要。在围绕三个美国城市（马里兰州巴尔的摩、马里兰州波士顿和宾夕法尼亚州匹兹堡）的六个城市化流域中，我们重建了 1900 年以来的发展模式历史，并评估了流域发展过程中溪流变化的幅度和时间。发展重建表明，大多数流域发展发生在人口增长高峰时期，通常是在 1950 年至 1970 年间。河流流量记录表明，所有六个流域的年高流量事件频率显着增加，五个流域的年径流效率显着增加。生长高峰期的年开发强度与开发前后高流量频率变化幅度的相关性最强。结果表明，高峰生长期的时间对于了解水文变化特别重要，因为它可以确定流域内安装的雨水基础设施的类型。在三个流域中，快速（约 10-15 年）转向更频繁的高流量事件，在四个流域中，转向更高的径流效率。断点分析表明，高流量频率的这些转变发生在 1969 年至 1976 年之间，径流效率的转变发生在 1962 年至 1984 年之间。结果表明，高流量变化的时间主要由每个流域的发展轨迹驱动，而径流效率变化的时间则由发展轨迹和极端天气事件的组合驱动。我们的研究结果强调需要细化城市河流退化的原因，以纳入逐渐与快速城市化对水文变化和水生生态系统功能的影响，并认识到水文变化的主要驱动因素在城市流域之间是异质的，并且随着时间的推移而变化。
Linking the type and timing of hydrologic changes with patterns of urban growth is essential to identifying the underlying mechanisms that drive declines in urban aquatic ecosystems. In six urbanizing watersheds surrounding three U.S. cities (Baltimore, MD, Boston, MA, and Pittsburgh, PA), we reconstructed the history of development patterns since 1900 and assessed the magnitude and timing of stream flow changes during watershed development. Development reconstructions indicated that the majority of watershed development occurred during a period of peak population growth, typically between 1950 and 1970. Stream flow records indicated significant increases in annual frequency of high-flow events in all six watersheds and increases in annual runoff efficiency in five watersheds. Annual development intensity during the peak growth period had the strongest association with the magnitude of changes in high-flow frequency from the pre- to post-development periods. Results suggest the timing of the peak growth period is particularly important to understanding hydrologic changes, because it can set the type of stormwater infrastructure installed within a watershed. In three watersheds there was a rapid (∼10-15 years) shift toward more frequent high-flow events, and in four watersheds there was a shift toward higher runoff efficiency. Breakpoint analyses indicated these shifts occurred between 1969 and 1976 for high-flow frequency and between 1962 and 1984 for runoff efficiency. Results indicated that the timing of high-flow changes were mainly driven by the development trajectory of each watershed, whereas the timing of runoff-efficiency changes were driven by a combination of development trajectories and extreme weather events. Our results underscore the need to refine the causes of urban stream degradation to incorporate the impact of gradual versus rapid urbanization on hydrologic changes and aquatic ecosystem function, as well as to recognize that the dominant drivers of hydrologic changes are heterogeneous among urban watersheds and vary over time.