Efficient water allocation strategy to overcoming water inequity crisis for sustainability of agricultural land: a case of Southern Punjab, Pakistan

The inequity of water allocation in the Indus Basin by the rotational method has created conflicts of interest leading to water scarcity for irrigated agricultural land. The arid region of the basin is affected the most, which demands a new inventive way of managing water resources. Geo-informatics maps of the Bahawalnagar canal circle were prepared which show groundwater quality and depth to water table (DWT) for 2006 and 2016, crop evapotranspiration (ETc) by using product MOD16A2 for Kharif (April to September) 2017 and Rabi (October to March) 2017-18 cropping season. Results showed that groundwater quality is deteriorating and DWT is rising over 72% of the study area which leads to waterlogging and salinization. Surface water deficit filled through groundwater contribution is 53.66% and 39%, while ETc varies from 0.0 to 931 and 0.0 to 1979 mm/season for the Rabi and Kharif cropping seasons respectively. This paper presents the status of water balance and groundwater characteristics of the arid region of the Indus basin and recommends re-evaluation of the current water allocation system both within and between canal command areas, recommending that water allocation should be allocated as per crop water requirement and groundwater quality. A re-allocation of water-based on groundwater characteristics will not only mitigate waterlogging and soil salinity, which is a threat to the sustainability of agricultural land but also reduces the stress of inequities within the current rotational system. Implementation of this water allocation strategy will require long-lasting monitoring of groundwater quality at a different depth, a variation of depth to the water table, and estimation of crop evapotranspiration.