CHANNEL GEOMETRY, BED MATERIAL, AND INFERRED FLOW CONDITIONS IN EPHEMERAL STREAM SYSTEMS, BARRIER RANGE, WESTERN N.S.W. AUSTRALIA
CHANNEL GEOMETRY, BED MATERIAL, AND INFERRED FLOW CONDITIONS IN EPHEMERAL STREAM SYSTEMS, BARRIER RANGE, WESTERN N.S.W. AUSTRALIA
复制标题
新南威尔士州西部障碍物范围内短暂水流系统的河道几何形状、床质和推断的流动条件
DOI：
10.1002/hyp.3360060404
复制
发表时间：
1992
影响因子：
3.2
通讯作者：
D. Dunkerley
中科院分区：
文献类型：
--
作者：
D. Dunkerley
在干旱的西北偏西，流经屏障山脉高地的河流是短暂的，由于传输损失，它们经历了远离高地的快速河道收缩。这些过程是根据沿着两条代表性河流收缩的低地河段的连续地点对河道形态和河床物质的调查记录下来的。河道宽度和深度在下游表现出较大的波动，但断面面积和最大河床面粒度呈很有规律的下降。根据河道容量和预测的临界流速和平均流速估算的洪流量也有规律地下降。对数线性模型很好地拟合了这些趋势，并以半距离，即以公里为单位的河道长度，其形态测量参数的值下降了50%来报告。推断河道收缩率和传输损失率与从流域高地段输送的流量成反比。不寻常的通道特征，包括河床中大量的树木生长，使得普通流动方程的应用变得困难，因为摩擦因素无法可靠地估计。在收缩的河流中，床面性质的系统变化，如这里所研究的，也对临界速度方程的应用有影响，并强调需要进一步研究沙漠河道。
Streams draining the Barrier Range uplands in arid western N.S.W. are ephemeral and undergo rapid channel contraction away from the uplands as a consequence of transmission loss. These processes are documented on the basis of surveys of channel form and bed material at sequential sites located along the contracting lowland reaches of two representative streams. Channel width and depth display considerable fluctuation downstream, but cross-sectional area and maximum bed surface grain size decline in a very regular manner. Flood discharge, estimated from the channel capacity and predicted critical and mean flow velocities, also declines regularly. The trends are well fitted by log-linear models, and are reported in terms of a half-distance, the channel length in km over which the value of a morphometric parameter declines by 50 per cent. Rates of channel contraction and transmission loss are inferred to be inversely proportional to the volume of flow delivered from the upland section of the drainage basin. Unusual channel characteristics, including extensive tree growth in the bed, make application of ordinary flow equations difficult, because friction factors cannot be estimated with confidence. Systematic changes in the nature of the bed surface in contracting streams such as those studied here also have implications for the application of critical velocity equations, and highlight a need for further study of desert channels.