Impact of Flood Spreading on Groundwater Level Variation and Groundwater Quality in an Arid Environment

In arid and semiarid areas, bimodal and high rainfall leads to infrequent flood that can be extremely damaging. To reduce the impacts of persistent intra-seasonal drought and also to reduce flood damaging in arid and semiarid areas, rainwater storage is a prerequisite that keeps water far from evapotranspiration, increases groundwater level and decreases flood hazards modification to exchange between surface water and groundwater through flood spreading, dams, etc. The purpose of this paper is to delineate and explain variations in groundwater recharge and groundwater quality along an ephemeral stream that has been modified by flood spreading. Groundwater samples were collected from 14 deep wells located at different distances from flood spreading projection area (FSPA) in 1 month interval during September 2005 to September 2008. Groundwater quality was followed via Na<Superscript>+</Superscript>, K<Superscript>+</Superscript>, Ca<Superscript>2+</Superscript>, Mg<Superscript>2+</Superscript>, Cl<Superscript>-</Superscript>, Hco<Stack> <Subscript>3</Subscript> <Superscript>-</Superscript> </Stack> SO<Stack> <Subscript>4</Subscript> <Superscript>2-</Superscript> </Stack>, Electrical Conductivity (EC) and pH measurements for two time periods between 2005 and 2008. The results show significant impact of flood spreading in groundwater table and groundwater salinity variation. Groundwater table decreased in all study wells, but groundwater drawdown increased by increasing the distance to FSPA (during 4 years study, 11.02 m in the well located at 20 m of FSPA versus 38.88 in the well located at 1,825 m). Also ion concentration increased in all of the wells during the study period, but the increasing ion concentration was significantly less important in FSPA closeness. Copyright Springer Science+Business Media B.V. 2012