Quantifying the migration rate of drainage divides from high-resolution topographic data
Abstract. The lateral movement of drainage divides is co-influenced by tectonics, lithology, and climate, and therefore archives a wealth of geologic and climatic information. Several methods have been proposed to determine the direction of drainage-divide migration. However, how to quantify the migration rate of drainage divides remains challenging. Here, we propose a new approach to calculate the migration rate of drainage divides from high-resolution topographic data. The new method is based on the cross-divide comparison of channel-head parameters, including the critical upstream drainage area and the gradient of channel head, both of which are used to calculate the normalized channel steepness at the channel head. We then apply the new method to an active rift shoulder (Wutai Shan), and a tectonically stable area (a mountain range in the Loess Plateau) in North China, to illustrate the calculation of drainage-divide migration rates. The northward migration rates at the Wutai Shan range from 0.10 to 0.13 mm/yr. The migration rates are approximately zero at the mountain range in the Loess Plateau. This study demonstrates that the migration rate of drainage divides can be determined more accurately once the cross-divide differences in uplift rate are taken into account.
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