THE EVOLUTION OF TIDAL CREEK NETWORKS, MARY RIVER, NORTHERN AUSTRALIA
THE EVOLUTION OF TIDAL CREEK NETWORKS, MARY RIVER, NORTHERN AUSTRALIA
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DOI：
10.1002/esp.3290170205
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发表时间：
1992-03-01
影响因子：
3.3
通讯作者：
MILLS, K
中科院分区：
文献类型：
--
作者：
KNIGHTON, AD;WOODROFFE, CD;MILLS, K
50年来，潮汐小溪网络在澳大利亚北部的玛丽河沿岸平原向内陆延伸了30多公里，入侵了淡水湿地并破坏了相关的植被。通过主河道延伸和支流发育的结合，网络以指数速度增长，伴随而来的是小溪的拓宽。大的潮差，平原上非常小的海拔差异，以及先前存在的航道线(特别是以古航道的形式)的可获得性，一直是造成快速扩张的主要因素。这些网络与陆地网络在增长模式和平面特性方面存在密切的相似之处。当渗流区的扩散流通过局部冲刷变得集中时，就启动了一条渠道。随后的发育以长一级河道的快速延伸为特征，大多数支流增加发生在较晚的时间。模型测试表明，在早期阶段，外部链接更有可能发生分支，但随着时间的推移，外部链接和内部链接分支的可能性变得更均等。尽管主要小溪的源头似乎已经达到极限，支流充填仍将继续逆流而上。只有在最下游的部分才能接近稳定的排水密度，管网不仅满足排水网络组成的规律和随机模型的基本假设，而且与地面管网类似地偏离了拓扑的随机性。拓扑和长度属性在演进过程中都发生了变化，但在很大程度上是在链路而不是网络规模上。与地面网络的密切对应可能是由于低起伏和相对不受限制的增长性质，其中空间的可获得性是主要决定因素。
Tidal creek networks have in 50 years extended over 30 km inland across the coastal plains of the Mary River in northern Australia, invading freshwater wetlands and destroying the associated vegetation. The networks have grown at an exponential rate through a combination of main channel extension and tributary development, with concomitant widening of the creeks. A large tidal range, very small elevational differences over the plains, and the availability of preexisting channel lines (notably in the form of palaeochannels) have been major factors contributing to the rapid rate of expansion.Close parallels exist between these networks and terrestrial networks as regards modes of growth and planimetric properties. A channel is initiated when the diffuse flow of a seepage zone becomes concentrated through localized scour. Subsequent development is characterized by the rapid extension of long first-order channels, with most tributary addition occurring later. Model tests suggest that branching was more likely on exterior links in the early stages but that exterior and interior link branching became more equally likely through time. Although the headward limits of the main creeks seem to have been reached, tributary infilling will continue to progress upstream. Only in the most downstream parts is a stable drainage density being approached.The networks not only satisfy the laws of drainage network composition and the basic postulates of the random model but also depart from topologic randomness in similar ways to terrestrial networks. Both topologic and length properties have changed during evolution but largely at the link rather than network scale. The close correspondence with terrestrial networks may be due to the low relief and the relatively unconstrained nature of growth in which availability of space was the main determining factor.