Structural characteristics of pools in headstream areas
Structural characteristics of pools in headstream areas
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源头区水池结构特征
DOI：
10.1016/j.catena.2021.105760
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发表时间：
2022
期刊：
影响因子：
6.2
通讯作者：
Itsukushima Rei
中科院分区：
文献类型：
--
作者：
武若 聡;内堀 圭一郎;海老原 友基;森 信人;武若聡;武若聡;Itsukushima Rei;Itsukushima Rei
在山区河流的河床形态中，泥沙起着重要的作用。它们提供栖息地并有助于能量耗散。然而，他们只得到了边缘的关注相比，台阶结构，其形式和驱动因素，如河道特征和上游形态的结构特征，仍然不清楚。因此，本研究的目的是确定油气藏的结构特征，包括形态、大小和存款条件，以及控制它们的因素。根据对长江口9524 m河道428条河段1302个油气藏的现场调查结果，对花岗岩、流纹岩和砂岩3种岩石类型的油气藏间距、形态、规模、存款条件与控制因素之间的关系进行了研究。用池间距除以槽宽计算出的平均池间距分别为：跌水池8.80、梯级12.87、阶梯水池4.56和浅槽16.14。这是由于目标河流是一级河流，宽度小，以及它们的区域性特征，即很少有木材堵塞和强迫池。此外，油气藏的沉积深度因地质而异。花岗岩、流纹岩和砂岩的最大沉积百分比分别为78%、33%和34%。因此，花岗岩中的沉积作用明显大于流纹岩和砂岩源头地区。这可能是由于花岗岩的不连续风化过程中，它被分解成大尺寸的核心石和细颗粒。根据地质情况，这些池塘的沉积环境不同，这表明利用这些池塘作为栖息地的生物群也可能不同。然而，缺乏对池塘微生境的研究，需要对生态系统的未来前景进行研究。
Pools play an important role among stream bed morphologies in mountain streams. They provide habitat and contribute to energy dissipation. However, they have received only marginal attention compared with step structures, and their forms and driving factors, such as stream-channel characteristics and structural characteristics of upstream morphologies, remain unclear. Therefore, the purpose of this study was to determine the structural characteristics of pools, including morphology, size, and deposit conditions, and the factors controlling them. Based on the results of a field survey for a channel length of 9524 m, with 428 reaches and 1302 pools, the correlations between the pool spacing, morphology, size, and deposit conditions of the pool, and controlling factors were investigated for three rock types (granite, rhyolite, and sandstone). The average pool spacing calculated by dividing the interval length of the pool by the channel width was 8.80, 12.87, 4.56, and 16.14 for fall-pool, cascade, step-pool and pool-riffle respectively. This is due to the fact that the target streams are first-order streams with small widths as well as their regional characteristics, that is, few log jams and forced pools. In addition, the depositional depth of the pools varies depending on the geology. The maximum percentage of sediment deposition in the pool was 78%, 33%, and 34% for granite, rhyolite, and sandstone, respectively. Thus, the sedimentation in granite is significantly greater than in the rhyolite and sandstone headstream areas. This is probably due to the discontinuous weathering of granite during which it is broken down into large-sized core stones and fine grains. The difference in the depositional environment of the pools depending on the geology indicates that the biota that use those pools as a habitat may also differ. However, research on the microhabitats of pools is lacked, and research regarding the future perspectives of ecosystems is required.