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Werner A.D.,Flinders University | Zhang Q.,CAS Nanjing Institute of Geography and Limnology | Xue L.,Tianjin Lonwin Technology Co. | Smerdon B.D.,CSIRO | And 6 more authors.
Water Resources Management

The state of groundwater systems worldwide is presently not well defined, and in particular there is little context for agencies responsible for managing water resources to evaluate occurrences of groundwater depletion against other cases globally. In this study, an initial inventory of groundwater depletion problems is compiled and ranked to identify the world's most critical cases, i. e. situations of groundwater mega-depletion. The ranking is based on an indexed approach that considers overdraft, drawdown and subsidence, plus the importance of the resources in terms of population-dependency and rates of extraction. The five most highly ranked depleted aquifers of the world include the shallow aquifers of the Hai River Plain (China), the Altiplano region (Spain), the Mexico Basin (Mexico), the Huang River basin (China) and the California Central Valley (USA). An abridged account of modelling to assess drawdown is described for the Hai River Plain, revealing that despite recharge in the order of 13,000 GL/yr, an overdraft of about 8,000 GL/yr is occurring to support the vast population of the region. This has led to up to 100 m of drawdown in places and reports of subsidence of several metres. The Hai River situation demonstrates that falling water levels may not act to alleviate pumping stresses; a symptom of unchecked extraction and an exemplary illustration of the tragedy of the commons. The causal factors leading to mega-depletion are varying across the globe and each mega-depletion case contains unique elements, although population appears to be an important factor. © 2012 Springer Science+Business Media Dordrecht. Source

Yu L.,Haihe River Water Conservancy Commission | Yu L.,Tianjin Lonwin Technology Co. | Yang J.,Haihe River Water Conservancy Commission | Xu L.,Tianjin Lonwin Technology Co. | And 5 more authors.
Jilin Daxue Xuebao (Diqiu Kexue Ban)/Journal of Jilin University (Earth Science Edition)

In order to further study the influence of various climate changes and hydrological factor on arid changes in Haihe River basin, we analyze temperature, precipitation and runoff of Haihe River basin by Mann-Kendall nonparametric tests. We also analyze the drying characteristics by the method of Z index. The results show that the drought of Haihe River basin has changed from wet to normal to dry since the 1950 s. At the beginning of the 21 st century, the northern basin became a little drought. Mostly, the area coverage is lower than 40%, but there were also some drought that covered more than 98% of the area. From the time, the 1980 was a watershed in droughts occurrence. In terms of both the frequency and on the average coverage, it was more dry after 1980 than before. From the drought occurrence frequency, mild and general drought of Haihe River basin in high frequency distributed in the Luanhe River basin as well as the northern mountains, and in central plains region the drought frequency is relatively low. Major drought event occurred more frequently in central and southern plains region. Overall, the drought occour frequence in Luanhe River basin is the highest, and the eastern region of Haihe River basin is much lower, and the western region is relatively low frequency. Source

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