Evolution study of a regional groundwater system using hydrochemistry and stable isotopes in Songnen Plain, northeast China

Abstract

Abstract:Groundwater is often a critical source of water for municipal, industrial and agricultural uses, especially in arid and semi-arid environments. Songnen Plain, located in the central part of northeast China, is such a region, it being an important productive base of commodity grain in this country. In the past two decades, groundwater quality in the region, especially salinization, has deteriorated under natural changes and human activities, and has become a crucial factor restricting sustainable ecoenvironmental and socio-economic development. In this paper, The Taoer River catchment, situated in the middle of the region, was selected as the study area for the groundwater quality evolution study using hydrochemistry and stable isotopes to obtain a better understanding of the system. Fifty-two groundwater samples were collected with systematic design during the low-water and high-water periods in 2003. A series of comprehensive quality data interpretations, e.g. statistics, ratios of ions and Piper diagrams, together with stable isotope data, have been used to gain an insight into the spatial and temporal variations and evolution laws of groundwater hydrochemistry. The following main hydrochemical processes were identified as controlling the water quality of the groundwater system: weathering-dissolution, evaporation-condensation, ion-exchange reactions and groundwater salinization. This latter process, salinization, is the most important process and is caused by the leaching of superficial or near-surface salts from the saline-alkaline soil into shallow groundwater.

The relationship between and evolution of surface water and groundwater in Songnen Plain, Northeast China

“…5). Water evolution proceeds from Ca-Mg-HCO 3 to Na-HCO 3 by the evaporation and ion exchange of calcium in the water for the sodium in the soil (Edmunds et al 1982;Edmunds 2003;Zhang et al 2007).…”

“…Research on the hydrochemical processes governing groundwater is a vital task to water and environment management (Zhang et al 2007). The groundwater exchanges with the river channel creating gaining, losing, flow through and parallel flow reaches in the fluvial plain (Woessner 2000).…”

“…It is one of the three major regions of occurrence of soda saline-alkali soil in the world (Zhang et al 2007). Natural factors of alkalization are parent materials, topographic positions, freeze-thaw action, wind conveyance, water properties and semi-arid/sub-humid climate.…”

“…Because of water shortage and expenditure problems, local farmers have abstracted groundwater with high salinity from the unconfined aquifer for irrigation in the dry land. Thus, a large area of secondary saline-alkaline land has been induced and the slightly saline-alkaline land has been aggravated (Zhang et al 2007).…”

“…Groundwater issues are well documented in the literatures (Zhang et al 2007;Xiao et al 2009;Liu et al 2011). However, the combined study of surface water and groundwater has been little documented (Zhang et al 2012).…”