Devi, Khangembam SharmilaSingh, Kshetrimayum Krishnakanta2024-01-212024-08-142024-01-212024-08-142021-06-2572105010.1002/gj.4198http://10.2.3.109/handle/32116/4119The main sources of water resources of the Barak Valley of Northeast India for irrigation are the surface water bodies in the form of ponds, lakes, rivers, and groundwater. This paper elucidates insight into the irrigational parameters to classify the types of water, based on these indices. Total hardness shows that 90% of surface water belongs to the soft and 63% of groundwater samples belong to the soft category. C-S plot shows 33% of surface water belongs to C1-S1 and 66% of groundwater samples belongs to C1-S1 and C2-S1, indicating fresh and suitable for use. The percentage Na+ shows most samples belong to good and permissible categories. Permeability index shows 81% of surface water in Class II and 18% in Class III, indicating good and bad types, respectively. Kelly's index suggests 90% of surface water is suitable and 9% is unsuitable, while 14% of piedmont groundwater is unsuitable. Magnesium hazard reveals 18% of surface water has more than 50 Magnesium absorptio ratio, leading to unsuitable, while 28% of piedmont and 33% of flood plain groundwater samples belong to unsuitable. Residual sodium carbon suggests surface water as suitable, while 48%, 12%, and 6% of groundwater belong to suitable, marginal, and unsuitable categories, respectively. Irrigation Water Quality Index values indicate that surface water is characterized by a highly restricted class, as they are exposed to surficial contamination as compared to groundwater. Base exchange index of ions indicates Na+-SO4?2 hydro-facies type suggesting dissolution of salt minerals in weak acidic water. Meteoric genesis index of ions reveals the source of groundwater as deeper meteoric water. Thus, the present study indices that the surface water bodies such as ponds, lakes, and swamps are more prone to contamination, leading to unsuitability for irrigational use, as compared to shallow groundwater in the study area, and therefore, appropriate measures must be adopted to reduce the quality deterioration for maximum utilization. � 2021 John Wiley & Sons Ltd.en-USassessmentBarak valleyirrigational indicesNortheast IndiaqualityAssessment of irrigational indices in surface water and shallow groundwater in the alluvial plain of Barak Valley, Assam, Northeast IndiaArticlehttps://onlinelibrary.wiley.com/doi/10.1002/gj.4198Geological Journal