Impacts of afforestation on groundwater resource: a case study for Upper Yazoo River watershed, Mississippi, USA

Groundwater resource overdraft is a serious water resource concern worldwide. Although afforestation has been recognized as conserving water resources, improving water quality and mitigating river flood, the role it plays with groundwater resources is not fully investigated. Here we applied the US Geological Survey's Mississippi Embayment Regional Aquifer Study (MERAS) 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.