Abstract

Groundwater resource overdraft is a serious water resource concern worldwide. Although afforestation has been recognized for conserving water resource, improving water quality and mitigating river flood, its role on groundwater resource is not fully investigated. Here we applied the US geological Survey’s MERAS (Mississippi Embayment Regional Aquifer Study) model to estimate impacts of afforestation in croplands on groundwater resource availability in the Upper Yazoo River Watershed (a humid subtropical climate), Mississippi, USA. Simulations showed that the average groundwater level had declined 1.2 m in the croplands over a 20-year period from 1987 to 2007, whereas the average groundwater level had declined only 0.13 m after afforestation for the same simulation period and occurred mainly due to no groundwater pumping and a slight increase in groundwater recharge. Our study implies that afforestation on low productive croplands in a humid subtropical region could be an alternative to mitigate groundwater depletion.

摘要

地下水资源透支是世界范围内严重的水资源问题。尽管植树造林已被公认为可以节约水资源，改善水质和减轻河流洪水，但其在地下水资源中的作用尚未得到充分研究。在这里，我们应用了美国地质调查局的MERAS（密西西比河沿岸地区含水层研究）模型来估算美国密西西比州上亚佐河流域（潮湿的亚热带气候）农田造林对地下水资源可用性的影响。模拟显示，从1987年到2007年的20年中，农田的平均地下水位下降了1.2 m，而平均地下水位仅下降了0。造林后13 m处于相同的模拟时期，发生的主要原因是没有抽水和地下水补给量略有增加。我们的研究表明，在亚热带湿润地区低产农田上进行植树造林可以减轻地下水的消耗。