Economic impact of the groundwater overdraft on agriculture: A case study of the Neishaboor plain

In the last decade, various aspects of groundwater resource depletion have gained a special place among water sector experts and decision makers. Research in this area is relatively new in most parts of the world. Groundwater depletion, which has been in a concerning state for most plains in Iran in recent years, has various consequences which impede sustainable development. One of the most important consequences of the dropping groundwater table is its impact on the economy of the agricultural sector. A problem that, despite its obviousness and bi-directionality, has rarely been quantified. In this research, it is attempted to simulate the status of groundwater resources under the influence of continued groundwater overdraft until 1420 (2041), on the basis quantitative (harvestable water) and qualitative (electrical conductivity) effects on the economic status of agricultural sector using cultivation area indices. We examine agricultural products, their performance, farmers’ income, and labor force. Questionnaires were used to estimate costs and incomes and the results of combined modeling of surface and groundwater in Neishaboor plain were used to estimate the amount available water. The model predicted a decrease of up to 24 m in water table and an average increase in salinity of 5500 mmhos/cm for the Neishaboor plain. The effects of the occurrence of these events was then modeled. Based on models for cropping patterns, water-yield equations, and salinity patterns, we estimated a 30% reduction in area under cultivation, a 65% decrease in crop yields, and a 28% decrease in labor force by 2041. Over the next 20 years, these impacts will significantly reduce revenues in the agricultural sector in Neishaboor plain, which will pose important secondary problems and consequences.