Groundwater recharge assessment and long-term simulation for managing the threat of salinization of irrigated lands

The advancement of irrigated agriculture is indispensable to satisfy the growing food demands of the world's prospering population. It is also essential for accomplishing many UN SDGs (United Nations' Sustainable Development Goals) such as SDG1 (No Poverty), SDG2 (Zero Hunger), and SDG15 (Life on Land). Without proper management, however, irrigation advancement can cause twin hydrological problems, i.e., rising aquifer levels and salinization in irrigated areas. Currently, more than a fifth of the total worldwide irrigated region is adversely affected by these problems. Furthermore, whenever left unaddressed, these problems could spread to more than half of the irrigated lands worldwide by 2050. To evaluate the aforesaid issues in an irrigated region of India, this study first developed a water balance model to assess the long-term groundwater recharge which would help to understand the system dynamics of the problems. Then, after analyzing the results, a simulation model was set up for the study region considering local agro-hydro-climatic and soil conditions. The approach used is the first of its kind in the selected study region and it will offer a better comprehension of the dynamics of the processes that guide the system imbalances. The presented approach is novel and easy to follow and it can also be replicated in other parts of the world dealing with comparative issues. The model's performance was evaluated statistically before being applied. The models performed very well as evidenced by high R-squared values and model efficiency, and low ME and RMSE values. The groundwater recharge analysis revealed that the aquifer levels have been rising for the last two decades and they will continue to rise if no preventive measures are implemented. The simulated scenarios showed that under the base case alternative the aquifer levels will increase at a mean yearly rate of 0.08 m. Hence, apt management plans such as altered cropping pattern, conjunctive water use, and canal lining are recommended. The most favorable scenario divulged that even a little alteration of two to six percent in different inputs would contain the region safe from the problems mentioned above.

Automated summary

The advancement of irrigated agriculture is crucial for meeting the growing food demands of the world's population and achieving sustainable development goals. However, without proper management, it can lead to rising aquifer levels and salinization in irrigated areas. Currently, over a fifth of irrigated lands worldwide are affected by these problems, and if left unaddressed, they could spread to over half of the irrigated lands by 2050. This study developed a water balance model and simulation model to assess the situation in an irrigated region of India and recommended management plans such as altered cropping pattern and canal lining.