The human–landform interaction in the region of the Ghaggar–Hakra palaeochannel in the northwest Indo‐Gangetic plains during the Bronze Age Indus/Harappan civilisation (~4.6–3.9 thousand years before the present, ka bp) remains an enigmatic case due to a paucity of evidence regarding the hydrology of the then existing river. Here, we estimated the palaeohydrology of the foothill Markanda River in the sub‐Himalayan catchment of the Ghaggar–Hakra (G–H) palaeochannel. Our morphology and chronology results show aggradation of a fan (57.7 ka) during the Late Pleistocene and T–1 to T–5 fluvial terraces (13.1 to 6.0 ka) during the terminal Pleistocene to Holocene, and deposition of palaeoflood sediments (3.9–3.8 ka) over the T–3 terraces during the Late Holocene. Considering the known uplift rates along the Himalayan frontal thrust, and our estimated aggradation rates, we derived channel palaeogeometry and calculated peak discharge at the site of palaeoflood deposits. We conclude that the Markanda River's peak discharge was several orders of magnitude higher during the Late Holocene than the modern‐day peak discharge of 100‐year return period. The palaeoflood deposits represent larger flooding of the foothill rivers that sustained flows in the downstream reaches of the Ghaggar–Hakra palaeochannel during the Late Harappan civilisation.

中文翻译：

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在哈拉潘时代，喜马拉雅山麓山河的大洪水使Ghaggar–Hakra河道持续流动

青铜时代印度/哈拉潘文明时期（约4.6-3.9万年前，ka bp），西北印度－恒河平原加格加－哈克拉古河道区域的人地相互作用）由于当时存在的河流的水文状况的证据不足，仍然是一个令人费解的案例。在这里，我们估算了Ghaggar–Hakra（G–H）古河道的喜马拉雅河次流域山麓Markanda河的古水文学。我们的形态和时间顺序结果显示，晚更新世期间扇形（57.7 ka）的沉积，更新世末至全新世期间T-1至T-5的河床阶地（13.1至6.0 ka）的沉积和古洪水沉积物的沉积（3.9-3.8） ka）在全新世晚期的T–3阶地上。考虑到沿喜马拉雅山前向推力的已知上升速度，以及我们估计的凝结速度，我们推导了古河道，并计算了古洪水沉积点的峰值流量。我们得出结论，马坎达河 全新世晚期的峰值排放量比100年回归期的现代峰值排放量高出几个数量级。古洪水沉积物代表了山麓河流的大洪水，这些山丘河在哈拉潘晚期文明时期一直在加格-哈克拉古河道的下游持续流动。