Characterizing groundwater and surface-water interaction using hydrograph-separation techniques and groundwater-level data throughout the Mississippi Delta, USA

Characterizing groundwater and surface-water interaction using hydrograph-separation techniques and groundwater-level data throughout the Mississippi Delta, USA | Caractérisation des interactions entre eaux souterraines et eaux de surface à partir des techniques de séparation d’hydrogramme et des données de niveaux d’eaux souterraines dans le Delta du Mississippi, Etats Unis d’Amérique Caracterización de la interacción entre las aguas subterráneas y las aguas superficiales mediante técnicas de separación de hidrogramas y datos de nivel de las aguas subterráneas a través del delta del Mississippi, EEUU 利用过程线分割技术和地下水位数据表征美国密西西比三角洲地下水地表水相互作用 Caracterização da interação água superficial–água subterrânea utilizando técnicas de separação de hidrógrafas e flutuação do nível d’água subterrâneo em todo o Delta do Mississipi, EUA

2019

The Mississippi Delta, a portion of the Mississippi Alluvial Plain (MAP) located in northwest Mississippi (USA), is an area dense with industrial-level agriculture sustained by groundwater-dependent irrigation supplied by the Mississippi River Valley alluvial aquifer. Observed declines in groundwater-level elevations and streamflow, contemporaneous with increases in irrigation, have raised concerns about future groundwater availability and the effects of groundwater withdrawals on streamflow. To quantify the impacts of groundwater withdrawals on streamflow and increase understanding of groundwater and surface-water interaction in the MAP, hydrograph-separation techniques were used to estimate baseflow and identify statistical streamflow trends. The analysis was conducted using the US Geological Survey Groundwater Toolbox open-source software and daily hydrologic data provided by a spatially distributed network of paired groundwater wells and streamgage sites. This study found that statistically significant reductions in stream baseflow occurred in areas with substantial groundwater-level declines. The use of hydrograph-separation and trend analyses to quantify the impacts of groundwater withdrawals and the use of streamflow as a proxy for changes in groundwater availability may be applicable in other altered environments. Characterizing and defining hydrologic relations between groundwater and surface water will help scientists and water-resource managers refine a regional groundwater-flow model that includes the Mississippi Delta, which will be used to aid water-resource managers in future decisions concerning the alluvial aquifer.

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