Assessment of groundwater quality in sunamganj of Bangladesh
Huge quantities of groundwater, particularly from the shallow aquifers, are used for irrigation in Bangladesh and in the absence of adequate surface water in the dry season, irrigation becomes heavily dependent on groundwater. The water quality management is essential for long-term irrigation system as it persuades the soil properties. In irrigation water evaluation, emphasis is given on chemical and physical characteristics of water. The toxicity or suitability of groundwater is determined by varying amounts and different ions. The usual toxic elements in irrigation are chlorine, boron, and sodium, which are toxic to sensitive crops at low concentrations. Irrigation water quality is generally judged by some determining factors such as sodium absorption ratio (SAR), soluble sodium percentage (SSP), residual sodium carbonate (RSC), and electrical conductance (EC) (Richards, 1954). Along with the above indicators, some additional indices to categorize the groundwater for irrigation like magnesium adsorption ratio (MAR), Kelly’s ratio (KR), total hardness (TH), permeability index (PI), residual sodium bicarbonate (RSBC) should be studied. The location of this study area was the Sunamganj district, which lies in the “North-Eastern Depression” of Bangladesh. The depression is characterized by flat terrain with low land elevation. People of this district are the pioneer users of shallow and deep tube wells for drinking and irrigation purpose.