Effect of Groundwater Level on Salinity Content and Environmental Land Classification

Abstract

Saline affected soil is in the northeast of Thailand, especially in the Khon Kaen Province. The relation between the salinity accumulation in brackish groundwater and the groundwater level from ground surface represents the progress state of soil salinization. The practice for suitable land use against the salinization can be established when the main conditions of salinization hazards are known. Based on this concept, the electric conductivity (EC) of groundwater and its level were measured with piezometers for three years in an experimental field at Khon Kaen Province. The field data showed that the groundwater level much affected by salinity was less than one and half meters from ground surface in the investigated area, and it was confirmed that the saline soil was mainly caused by the capillary rise of brackish water and by the accumulation of salt occurred at the soil surface. Salt accumulation process was investigated by the change in groundwater level. The reducing effect of salinization caused by capillary water rise became remarkable when the groundwater level was lowered until ground surface soil was out of the dominant capillary water zone. This indicates the reduction of groundwater level was very effective in reducing salinization. Allowing for field experimental results, a classification map for environmental land use in saline affected area was proposed.