Hydro-chemical characteristics of the surface water bodies in Imphal Valley, Manipur State, North-East India

Chemical analysis of twenty five surface water samples collected from rivers and ponds (community and private) from different locations in the Imphal valley indicate that the river water has higher average pH, hardness, HCO₃⁻, CO₃², Mg²⁺, Na⁺, and TDS than the pond water. On the other hand, samples from ponds have greater average concentration of SO₄^2-, Cl⁻ and K⁺. This could be due to the different lithology, hydrodynamic conditions and anthropogenic activities prevailing at the sources of both the water bodies.

The water in the area belongs to Ca-Mg cation facies and CO₃-HCO₃ anion facies. Spatial variation of all major ions except sulphate and carbonate show southward increasing trend. The major ion concentrations are mainly contributed by rock weathering of the Disang Formation. Excess application of fertilizers and other anthropogenic activities along with the scattered presence of brine springs in the study area could be responsible for varied and abnormal ionic concentration in these waters.