Hydro-economic model framework for achieving groundwater, food, and economy trade-offs by optimizing crop patterns

Abstract

When allocating water resources, stakeholders (such as water departments, agricultural sector actors, and farmers) aim to maximize their benefits. This leads to conflicts between water savings, food security, and profit growth, causing major challenges for water managers. A hydro-economic model was developed to alleviate groundwater sustainability, food security, and economic growth (GFE) conflicts through crop pattern optimization. This model combines groundwater, agronomic, and economic sub-models to simulate spatiotemporal variations in groundwater level, irrigation requirement, crop production, and net profit. The NSGA-II algorithm was used to maximize net profits while minimizing groundwater extraction and food reduction through crop pattern optimization in irrigation areas and under crop production constraints. Then, using the Baoding Plain as the study area, three scenarios with no external water supply and nine scenarios with an external water supply of 0.3, 0.6, and 0.9 km 3 /y were designed. The present crop pattern caused a groundwater decline of 0.32 m/y and an overdraft of 0.61 km 3 /y. The three scenarios without external water supply showed different options for maximizing net profit, minimizing groundwater extraction, and minimizing food reduction without affecting food production, food self-sufficiency or groundwater sustainability. All three scenarios cannot simultaneously satisfy the GFE target. With an external water supply of 0.3 km 3 /y, only one scenario met the GFE target; with that of 0.6 km 3 /y, all scenarios met the GFE target; and with that of 0.9 km 3 /y, groundwater levels increased, profits overflowed, and food overproduction occurred.