Seasonal comparison of groundwater level and quality in the catchment of the Tonle Sap Lake, Cambodia

Abstract

Groundwater in the floodplain of Tonle Sap Lake has been used for domestic, agriculture, and small industries. The variation of surface water availability and increasing demand, cause the increasing of groundwater extraction especially during dry season. So far, the study on groundwater resources is extremely limited comparing to surface water in the Tonle Sap catchments. So that, this study focusses on groundwater quality and level from 27 wells in Kompong Thom, Siem Reap, and Preh Vihear province. Seasonal variation of groundwater level shows that groundwater level in Siem Reap is about 1.5m and 4.3m below the ground surface in rainy season and dry season respectively while in Kampong Thom province it is about 0.7m and 2m below the ground surface in rainy season and dry season, respectively. from in situ measurement, some parameters such as pH ranged from 4.1 to 8.1, total dissolved solid from 21 to 1200 mg/L, turbidity from 0 to 88 NTU, temperature from 28 to 31°C, ORP from −2.2 to 424mV, and EC from 35 to 2000 μSm/cm. The concentrations of major ions (Ca2+, Mg2+, K+, Na+, Cl−, SO4 2− and HCO3 −) were approximate or under the permissible value and it was suitable for irrigation.