Headstream areas, which are located in the uppermost reaches of mountain streams, are important sections for investigating the geomorphology of stream channels and their generative mechanisms, because they are close to sediment supply sources and generally suffer little anthropogenic impacts. In this study, the occurrences and characteristics of bed morphologies in a sandstone-dominated headstream area are explored at two scales—reach and unit—which are often overlooked. As a result of field investigations, cascades and step–pools were found to occupy the majority of the stream channel laterally at the reach scale. However, most of the elevation differences were accounted for by fall–pools, cascades, and step–pools, suggesting the importance of bed morphologies with large elevation losses in the headstream area. In addition, the characteristics of the bed morphologies at the reach scale were closely related to the longitudinal profiles of each stream. The mean gradients of the reach-scale bed morphologies were 46.9% for fall–pools, 23.9% for cascades, 16.8% for step–pools, and 5.9% for pool–riffles. At the unit scale, pools occupied the majority of the stream laterally, and > 80% of the elevation differences in all the studied rivers were occupied by falls, bedrock cascades, cascades, and steps. Although there have been no studies on the elevation loss functions and characteristics of falls, this study revealed the importance of fall–pool reaches and fall units in a sandstone-dominated headwater area in the Kantō Range of Japan.

源头区位于山区河流的最上游，靠近泥沙供应源，一般受人为影响较小，是研究河道地貌及其生成机制的重要地段。在这项研究中，以砂岩为主的源头流区地层形态的发生和特征在两个尺度 - 范围和单元 - 上进行了探索，这两个尺度经常被忽视。作为实地调查的结果，发现瀑布和阶梯水池在河段尺度横向占据了大部分河道。然而，大部分海拔差异是由落水池、瀑布和阶梯水池引起的，这表明在源头流区域具有大的高程损失的河床形态的重要性。此外，河段尺度的河床形态特征与每条河流的纵剖面密切相关。落差池的河床形态的平均梯度为 46.9%，级联为 23.9%，阶梯池为 16.8%，池浅滩为 5.9%。在单位尺度上，水池在横向上占据了大部分的河流，所有研究河流中> 80%的高差被瀑布、基岩梯级、梯级和台阶占据。尽管没有关于瀑布的高程损失函数和特征的研究，但这项研究揭示了日本关东山脉以砂岩为主的源区的瀑布-池河段和瀑布单元的重要性。落差池的河床形态的平均梯度为 46.9%，级联为 23.9%，阶梯池为 16.8%，池浅滩为 5.9%。在单位尺度上，水池在横向上占据了大部分的河流，所有研究河流中> 80%的高差被瀑布、基岩梯级、梯级和台阶占据。尽管没有关于瀑布的高程损失函数和特征的研究，但这项研究揭示了日本关东山脉以砂岩为主的源区的瀑布-池河段和瀑布单元的重要性。落差池的河床形态的平均梯度为 46.9%，级联为 23.9%，阶梯池为 16.8%，池浅滩为 5.9%。在单位尺度上，水池在横向上占据了大部分的河流，所有研究河流中> 80%的高差被瀑布、基岩梯级、梯级和台阶占据。尽管没有关于瀑布的高程损失函数和特征的研究，但这项研究揭示了日本关东山脉以砂岩为主的源区的瀑布-池河段和瀑布单元的重要性。所有研究河流中80%的高差被瀑布、基岩梯级、梯级和台阶占据。尽管没有关于瀑布的高程损失函数和特征的研究，但这项研究揭示了日本关东山脉以砂岩为主的源区的瀑布-池河段和瀑布单元的重要性。所有研究河流中80%的高差被瀑布、基岩梯级、梯级和台阶占据。尽管没有关于瀑布的高程损失函数和特征的研究，但这项研究揭示了日本关东山脉以砂岩为主的源区的瀑布-池河段和瀑布单元的重要性。