Department of Geology and Geophysics, Indian Institute of Technology Kharagpur, Kharagpur, West Bengal, India.
School of Environmental Science and Engineering, Indian Institute of Technology Kharagpur, Kharagpur, West Bengal, India.
Sci Rep. 2018 Aug 13;8(1):12049. doi: 10.1038/s41598-018-30246-7.
In summer (pre-monsoon) of recent years, low water level among the last few decades, has been observed in several lower Indian reaches of the Ganges (or Ganga) river (with estimated river water level depletion rates at the range of -0.5 to -38.1 cm/year between summers of 1999 and 2013 in the studied reaches). Here, we show this Ganges river depletion is related to groundwater baseflow reduction caused by ongoing observed groundwater storage depletion in the adjoining Gangetic aquifers (Ganges basin, -0.30 ± 0.07 cm/year or -2.39 ± 0.56 km/year). Our estimates show, 2016-baseflow amount (~1.0 × 10 m/d) has reduced by ~59%, from the beginning of the irrigation-pumping age of 1970s (2.4 × 10 m/d) in some of the lower reaches. The net Ganges river water reduction could jeopardize domestic water supply, irrigation water requirements, river transport, ecology etc. of densely populated northern Indian plains. River water reduction has direct impact on food production indicating vulnerability to more than 100 million of the population residing in the region. The results of this study could be used to decipher the groundwater-linked river water depletion as well as the regional water security in other densely populated parts of the globe.
近年来，在夏季（前季风期），人们观察到恒河（或冈格）河的几个下游河段出现了几十年来的低水位现象（在研究的河段，1999 年至 2013 年夏季的河水水位枯竭率估计在-0.5 至-38.1 厘米/年之间）。在这里，我们表明，这种恒河水位枯竭与地下水基流减少有关，这是由于毗邻的恒河含水层（恒河盆地）中正在观测到的地下水储存枯竭造成的（-0.30±0.07 厘米/年或-2.39±0.56 公里/年）。我们的估计显示，在一些下游地区，2016 年基流（约 1.0×10 米/天）已减少约 59%，从 20 世纪 70 年代灌溉抽水泵开始的时期（2.4×10 米/天）开始减少。恒河的净水资源减少可能危及印度北部平原人口稠密地区的家庭用水供应、灌溉用水需求、河流运输、生态等。水资源减少直接影响到粮食生产，表明该地区有超过 1 亿人口面临脆弱性。本研究的结果可用于解释与地下水有关的河流水资源枯竭以及全球其他人口稠密地区的区域水资源安全问题。
