JWSS - Journal of Water and Soil Science

Recently, virtual water trade has been introduced as a tool to solve the water scarcity of dry regions. The concept holds that water-rich countries and regions should produce and export water-intensive commodities to water-scarce countries and regions. In this study, the status of domestic and international virtual water trade was studied to assess water management in Iran in 2006 (which was considered as a normal year). The calculations showed that 18666 Mm3 of virtual water was traded through the exchange of agricultural products between the provinces. Fars and Tehran provinces were the largest exporter and importer of virtual water, respectively. Iran imported 9626 Mm3 and exported 2226 Mm3 of virtual water. Water footprint was 752 m3/cap/yr and water self-sufficiency was 82% in Iran. The virtual water content of the exported and imported products was 1159 L/kg and 677 L/kg, respectively. The results showed that water-scarce provinces such as Kerman, Hormozgan and Semnan were exporters of virtual water to other provinces and abroad, whereas water-rich provinces such as Guilan, Chaharmahal and Bakhtiari, Lorestan, Kordestan, West Azarbayjan, Kohgiloyeh and Boyr-Ahmad, and Kermanshah were the importers of virtual water. Therefore, water management can be improved by the improvement in international and inter-province virtual water trade. For this purpose, the cropping pattern and consumption pattern should be adapted to the virtual-water content of agricultural products for the long-term water conditions in Iran.

Estimating the ecological water footprint and the virtual water trade in different agricultural crops in arid and semi-arid regions can help better manage the limited water resources.This research calculated temporal and spatial ecological water footprint of rain-fed and irrigated almond production in national and provincial scale using during 2008 to 2014. The results show that annual average water footprint in rainfed almond is 9.2 m³/kg, which the share of green and grey water is 72% and 28%, respectively which Ilam and Kohgiloyeh & Boyerahmad have a largest share in green water footprint with 91% and 90%, respectively. In adition to, in irrigated almond, the annual average water footprint is 11.4 m³/kg, which the share of green, blue and grey water is 0.19%, 71% and 10%, respectively. Sistan & Balouchestan, Khuzestana and Hormozgan have the highest share in blue water footprint. The total volume of water footprint of rain-fed and irrigated almond production is 1923 and 8242 MCM, respectively. Also, results show that about 92 percent of the total volume virtual water (equivalent to 9343 MCM per year) in almond production, has been exported to other countries through the virtual water trade.

The water footprint is an analytical tool that offers a better and more comprehensive view of how consumers or producers engage with freshwater consumption. Given the water crisis in the country, particularly in Isfahan Province, this study aims to estimate and compare the direct and indirect water footprints of several large industries, including Mobarakeh Steel, Iron Smelting, Refinery, and Power Plant, located in the Zayandeh River Basin. After identifying the desired objectives and study areas, as well as confirming the availability of the required data, information was gathered from the selected industries. Two methods were then utilized to aggregate the entire chain and the sum of steps to calculate the water footprint in the researched industries. According to the calculations, the direct and indirect water footprint in the iron smelting industry amounts to 196.9 cubic meters per ton of steel annually, of which 4.026 cubic meters is attributed to direct consumption and 17.5 cubic meters to indirect consumption. In a refinery, 18.80 liters of water are consumed directly and indirectly to produce one barrel of product (gasoline or diesel). Additionally, the direct and indirect water footprint of the Islamabad power plant is 1,198,320 cubic meters per terajoule, equating to 4.31 liters per kilowatt hour. The results of this study indicate that the indirect water footprint in the analyzed industries is equal to or exceeds direct water consumption, with both being equally significant. Finally, it is important to note that the results of this study can support decision-makers and policymakers in the industry, including those in the iron and steel, refinery, and power plant sectors, in managing their water footprint.

The present study was conducted with the aim of quantitative and qualitative analysis of agricultural water consumption in Markazi Province, and calculated and examined water consumption at the level of 18 crops and 12 counties using the water footprint as a comprehensive indicator. A simultaneous study of the three components of the blue, green, and gray water footprint was conducted as an analytical tool to assess the amount and manner of water consumption. In this study, meteorological, agricultural, and input consumption data were used in the 2022-2023 crop year, and water footprint values were estimated in terms of units and totals by crop and county. The results showed that BWFU is strongly influenced by spatial factors (climate and precipitation) and plant characteristics (yield, crop type, and growth period). A difference of up to 98% in BWFU among different crops and a difference of more than 9 times in GWFU in rainfed compared to irrigated lands were observed. Also, GRWFU values exceeded BWFU for many crops, indicating a significant pollutant load from the use of chemical fertilizers. In addition to spatial factors and plant characteristics, the difference of 223 MCM between Saveh and Ashtian counties and the difference of 52.7 MCM between Shazand and Mahallat counties in BWF and GWF, respectively, indicate spatial differences in BWFU and cultivation area. Also, the difference in 1377 MCM between the GRWF of Arak and Ashtian counties is affected by the amount and type of fertilizer used, in addition to the cultivation area. In addition to improving performance, suggested management measures include reducing the cultivation area of high-consumption crops, expanding rainfed lands in high-rainfall areas, optimizing input consumption, and modifying the cultivation pattern in accordance with resources and climatic conditions in order to maintain the quantity and quality of water resources. Accordingly, the research results demonstrate the potential of the water footprint index in location-based and product-based analysis of water consumption and formulation of management responses.

Water scarcity has made the agricultural water footprint a critical measure for sustainable resource management, particularly in water-stressed regions such as Iran. This index depends on various factors, including climate, crop yield, dietary habits, and irrigation/agricultural efficiency, which can be estimated more rapidly using modeling approaches. The SSM-iCROP2 model is a simulation model that has been parameterized and evaluated for over 30 crop species in Iran and has been widely used in studies related to crop yield. Since sugar is a key energy source in the food basket, sugarcane occupies vast cultivated areas in the country. Sugarcane is primarily grown in Khuzestan province. This study aimed to apply the aforementioned model to estimate the blue and green water footprint of this strategic crop, using upscaling methods for both potential and farmer-managed conditions from 1992 to 2022. The results showed that the total water footprint of sugarcane (sum of blue, green, and gray water footprints) was 2,251 and 3,134 cubic meters per ton for potential and actual (farmer) conditions, respectively.