Department of Watershed Management Engineering, Faculty of Natural Resources, Tarbiat Modares University, Iran.
Watershed Management Engineering, Faculty of Natural Resources, Tarbiat Modares University, Iran.
Sci Total Environ. 2017 Jun 1;587-588:168-176. doi: 10.1016/j.scitotenv.2017.02.098. Epub 2017 Feb 27.
Quantitative response of the watershed health to climate variability is of critical importance for watershed managers. However, existing studies seldom considered the impact of climate variability on watershed health. The present study therefore aimed to analyze the temporal and spatial variability of reliability (R), resilience (R) and vulnerability (V) indicators in node years of 1986, 1998, 2008 and 2014 in connection with Standardized Precipitation Index (SPI) for 24 sub-watersheds in the Shazand Watershed of Markazi Province in Iran. The analysis was based on rainfall variability as one of the main climatic drivers. To achieve the study purposes, the monthly rainfall time series of eight rain gauge stations distributed across the watershed or neighboring areas were analyzed and corresponding SPIs and R RV indicators were calculated. Ultimately, the spatial variation of SPI oriented R RV was mapped for the study watershed using Geographic Information System (GIS). The average and standard deviation of SPI-R RV index for the study years of 1986, 1998, 2008 and 2014 was obtained 0.240±0.025, 0.290±0.036, 0.077±0.0280 and 0.241±0.081, respectively. In overall, the results of the study proved the spatiotemporal variations of SPI-R RV watershed health index in the study area. Accordingly, all the sub-watersheds of the Shazand Watershed were grouped in unhealthy and very unhealthy conditions in all the study years. For 1986 and 1998 all the sub-watersheds were assessed in unhealthy status. Whilst, it declined to very unhealthy condition in 2008 and then some 75% of the watershed ultimately referred again to unhealthy and the rest still remained under very unhealthy conditions in 2014.
流域健康对气候变化的定量响应对流域管理者至关重要。然而，现有研究很少考虑气候变化对流域健康的影响。因此，本研究旨在分析伊朗马赞德兰省沙赞德流域 24 个子流域在节点年份 1986、1998、2008 和 2014 与标准化降水指数（SPI）相关的可靠性（R）、弹性（R）和脆弱性（V）指标的时空变化。分析基于降雨变化作为主要气候驱动因素之一。为了实现研究目的，分析了分布在流域或邻近地区的 8 个雨量站的月降雨时间序列，并计算了相应的 SPI 和 R RV 指标。最终，使用地理信息系统（GIS）为研究流域绘制了 SPI 定向 R RV 的空间变化图。研究年份 1986、1998、2008 和 2014 的 SPI-R RV 指数的平均值和标准差分别为 0.240±0.025、0.290±0.036、0.077±0.0280 和 0.241±0.081。总的来说，研究结果证明了研究区域 SPI-R RV 流域健康指数的时空变化。因此，在所有研究年份中，沙赞德流域的所有子流域都被归类为不健康和极不健康状态。对于 1986 年和 1998 年，所有子流域都被评估为不健康状态。然而，到 2008 年，情况下降到极不健康状态，然后约 75%的流域最终再次回到不健康状态，其余的仍处于极不健康状态。
