Department of Water Science and Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran.
Department of Hydrology and Water Resources, Faculty of Water and Environmental Engineering, Shahid Chamran University of Ahvaz, Ahvaz, Iran.
Sci Rep. 2022 Jun 2;12(1):9228. doi: 10.1038/s41598-022-13143-y.
Assessment of streamflow variations under the influence of climate change and human activity is crucial for sustainable water resource management, especially in semiarid areas. In this study, we first used the Hydrograph Separation Program to separate and analyze the base flow index (BFI) that was impacted directly by human activity and precipitation as an important climate factor from 1967 to 2016 in the Dez River Basin. Second, the Mann-Kendall trend test was used to identify trends and change points. Then, the elasticity coefficient method was applied to calculate the impacts of natural factors and anthropogenic activities. The results of the separation methods showed that the sliding interval method produced a better performance. Furthermore; the analyzed trend test at the annual scale showed a significant decreasing trend for runoff as well as increasing trends for the baseflow index in the four of five sub-basins of the Dez River at confidence levels of 95% and 99%, while the average precipitation in these sub-basins was not significant. Additionally, at the seasonal scale in these sub-basins, the average precipitation in winter showed a significant downward trend, while runoff showed a decreasing trend and the BFI index showed increasing trends in winter, spring and summer. The abrupt change point was determined after the change in the BFI index; the runoff was reduced. The maximum change occurred in the sub-basin tireh which after change point from 1977 to 1993,runoff reduced - 1.49% comparison with the base period( from 1967 to 1976) also elasticity estimation was - 0.46,but after change point in Baseflow index from 1994 to 2016 runoff reduced - 55.02% and elasticity estimation was - 0.65. The baseflow index trend and elasticity estimation also indicated that intensive human activities had more significant effects on the Dez Basin's hydrological processes and streamflow variation.
评估气候变化和人类活动对径流量变化的影响，对于半干旱地区的可持续水资源管理至关重要。本研究首先使用水文分割程序，将直接受人类活动和降水影响的基流指数（BFI）与作为重要气候因素的降水从 1967 年至 2016 年在德兹河流域进行分割和分析。其次，使用 Mann-Kendall 趋势检验来识别趋势和转折点。然后，应用弹性系数法计算自然因素和人为活动的影响。分割方法的结果表明，滑动区间法的性能更好。此外，在年际尺度上的分析趋势检验表明，在德兹河流域的五个子流域中的四个子流域中，径流量呈显著减少趋势，基流指数呈增加趋势，置信水平为 95%和 99%，而这些子流域的平均降水量并不显著。此外，在这些子流域的季节性尺度上，冬季平均降水量呈显著下降趋势，而径流量呈减少趋势，基流指数在冬季、春季和夏季呈增加趋势。在基流指数变化后确定了突变点，径流量减少。最大变化发生在 tireh 子流域，在 1977 年至 1993 年的变化点之后，与基准期（1967 年至 1976 年）相比，径流量减少了-1.49%，弹性估计值为-0.46，而在基流指数的变化点之后，从 1994 年至 2016 年，径流量减少了-55.02%，弹性估计值为-0.65。基流指数趋势和弹性估计也表明，人类活动的加剧对德兹流域的水文过程和径流量变化产生了更显著的影响。
