Water Shortage Management in Hirmand Catchment under Overseas Cultivation Strategy Using WEAP Model

The uneven distribution of water in the world has caused many countries to face water shortages. The lack of water has made the production of agricultural products a challenge. Water-scarce countries invest in the farms of water-rich countries as a strategy to provide needed agricultural products. This strategy is known as extraterritorial cultivation. The Hirmand watershed is facing limited water resources due to its dependence on the Hirmand transboundary stream from Afghanistan. In this research, the aim is to simulate the strategy of extraterritorial cultivation of agricultural products in order to manage water shortage in the Hirmand catchment area. In this regard, the Hirmand watershed was modeled using the WEAP model, and the current and future status of water resources and uses were simulated. Then the extraterritorial cultivation strategy was simulated as a scenario. Wheat, barley, and corn products were selected as the target of extraterritorial cultivation. The results showed that in the current situation, the Hirmand catchment area faces a water shortage of 582.812 million cubic meters per year, and 41.16% of the water demand in the Hirmand catchment area is not met. 72.42 percent of the total water shortage in the Hirmand catchment area is related to the agricultural sector, and 27.58 percent is related to the environmental sector. After applying the extraterritorial cultivation strategy, the water shortage in the agricultural sector is reduced by 93.89% and reaches from 364.524 million cubic meters per year to 22.242 million cubic meters. In the environmental sector, the water shortage will decrease by 95.19% from 219.911 million cubic meters per year to 10.570 million cubic meters per year. Applying the extraterritorial farming strategy has redistributed water resources in the Hirmand catchment area.