科研之友
微信
新浪微博
Facebook
分享链接
摘要
In many Asian megacities, the excessive use of confined groundwater has caused drastic decline of piezometric level with succeeding severe problems such as land subsidence and groundwater salinisation. At the same time, it may have enhanced groundwater recharge via an increase in vertical and/or lateral hydraulic gradient. The strength and spatiotemporal variation of the enhanced recharge are expected to depend on geographical and/or hydrogeological settings of an area in question. In the present study, the Bangkok basin in Thailand was selected to examine characteristics of enhanced recharge due to excessive pumping. We carried out numerical experiments on this phenomenon for half a century using a three-dimensional groundwater flow model. The model reproduced well observed hydraulic-head variations. Model outputs showed clearly that confined groundwater recharge under natural conditions (e. g. without pumping) occurred only in suburban hilly areas corresponding to deep aquifer outcrop areas, while recharge was enhanced due not only to suburban pumping urban areas mantled in thick clay (i.e. Bangkok metropolitan area). Recharge flux response to temporal variation in groundwater pumping was faster in urban areas and slower in remote hilly areas. On the plain, enhanced recharge was more distinct at locations where the Bangkok clay is relatively thin. These results suggest that piezometric level decline can be mitigated if appropriate sites are selected for groundwater pumping.
- 出版日期2011-8-15
