| Hongshan spring, as one of the19largest karst springs in Shanxi, China, is the main source of water supply for the local industry and agriculture. Karst groundwater in the spring area plays an important role in the economic and social development. However, the discharge of Hongshan spring has been attenuated year by year in the1980s. The annual average spring discharge is1.29m3/s from1955to1983, while from1984to1997the average discharge is0.91m3/s. The discharge is in a large slop rate after1997. Hongshan spring is on the verge of drying up while the discharge is only0.039m3/s in2013. Therefore, discussing the attenuate cause and forecasting the future discharge have important practical significances for the sustainable utilization of water resources and the local water ecological civilization construction.Based on the previous results and comprehensive investigation of field, the space boundary conditions were confirmed in Hongshan spring area. Meanwhile, the storage conditions, hydrodynamic and chemical characteristics, as well as the water level regime were analyzed to deepen the understanding of karst water system in Hongshan spring.Analysis of the annual and interannual regime of discharge, and the test for attenuation trend of Hongshan spring discharge by the Kandel rank correlation test to proved that the attenuation trend is obvious from1955to2013. At the same time, the water balance analysis in Hongshan spring area was carried out in three phases. The results show that Hongshan spring area in natural state is in positive equilibrium from1955to1983. From1984to1997with tiny influence of human activities and from1998to2013with strong influence of human activities, Hongshan spring area was in negative equilibrium. In addition, the annual average negative equilibrium quantity is proportional to the strength of human activities.Discussing the attenuation reason of Hongshan spring discharge shows that it is caused not only by the natural factors, such as gradually reduced precipitation, but also by the increasing exploitation and mine drainage quantity. Considering the lagged effect of rainfall to the spring discharge or restore discharge, the time-lag effect in Hongshan spring was studied by the grey relational grade calculation model.The results show that the lag age of rainfall to the spring discharge is3years,6years and8years in natural state, with tiny influence of human activities and strong influence of human activities, respectively. With the strengthening of human engineering activity, the time-lag of rainfall to Hongshan spring discharge is gradually extended.In view of the attenuation state of Hongshan spring, using the effective precipitation, which calculated from weighted averages of the time-lag precipitation, as a related sequence of restore spring discharge, the future spring discharge from2001to2013was predicted by GM(1,2) model and residual error correction of GM(1,2) model, respectively. After the contrast of the residual testing, the revised model has a higher accuracy in line with the actual situation.Using the Residual error correction model of GM(1,2), the spring discharge with different rainfall guaranteed rate was predicted by four different options from2014to2018. The results show that in the rainfall guaranteed rate of95%, the Hongshan spring will dry up in the end of2015with the unchanged human engineering activities (the exploitation with7.48million m3, and the mine drainage quantity with8.84million m3); with the exploitation in constant and the mine drainage quantity in half, the spring will dry up in2016. And in the rainfall guaranteed rate of75%, the spring will dry up in2017with exploitation in half and the mine drainage in constant; with both the exploitation and the mine drainage quantity in half, Hongshan spring will dry up in2018. Taking the effective measures to protect Hongshan spring is the urgent need to ensure the economic and social sustainable development... |
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