自新近纪晚期和第四纪早期以来,许多内流盆地转换成了外流盆地。内流湖水突然外泄,给下游流域带来大量的水。外源流水的注入重塑流域地貌并影响流域内河流的演化。基于有限体积方法,对外源流水对隆升河流地貌的重塑过程进行数值实验分析。主要结论为:外源流水注入后,下游主河道被深切。支流受侵蚀基准点下降的影响开始加速下切,整体流域的高程逐渐降低。当外源流水流量较大时,下游流域会袭夺相邻流域。河流下切系数控制流域开始袭夺的时间。河流下切系数和外源流水流量控制流域袭夺速度。流域重塑后的平均高程依赖于地表隆升速率、河流下切系数和外源流水流量。外源流水引起的流域袭夺过程可用于解释晋陕黄河与汾河流域的演化过程。
Since the late Neogene and early Quaternary, many endorheic basins have been transformed into exorheic basins. The transformation of the endorheic lake brings a large amount of water to its downstream drainage. The inflow of exogenous water reshapes the drainage landscape and influences the evolution of rivers within the basin. Based on the finite volume method, we present a numerical experimental analysis of the coupling effect between the exogenous inflow and the uplifting landscape evolution. The result indicates that the exogenous inflow will deeply incise the main downstream channel. The tributary incision is enhanced with the erosion basis's elevation decreasing, and so the elevation of the overall drainage gradually decreases. When the exogenous inflow discharge is large enough, the downstream drainage captures its adjacent drainage. The incision coefficient controls the time that the drainage capture begins. Two factors affect the drainage capture velocity: the incision coefficient and the exogenous inflow discharge. The average elevation of the drainage depends on the uplift rate, the incision coefficient, and the exogenous inflow discharge. The numerical results provide useful insights into the evolution of the Jinshan Yellow River and Fen River drainage.
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