بررسی تغییرات روند ردپای آب در محصولات مختلف بخش‌های اقتصادی ایران

امروزه با محدودیت منابع آب، بررسی اقتصادی بهره وری آب از اهمیت بالایی برخوردار است. در این بین ردپای آب یکی از مهم ترین مسائلی است که می توان آن را از نظر اقتصادی بررسی نمود. لذا پژوهش حاضر تغییرات ردپای آب در ایران را برای سال های 1380، 1390 و 1395 با استفاده از مدل اقتصادی داده- ستانده مورد بررسی قرار داده است. این پژوهش، بر اساس مدل داده- ستانده، رویکرد از بالا به پایین به سنجش و بررسی مصرف آب در بخش های اقتصادی کشور ایران پرداخته است. برای بررسی تکمیلی از شاخص های مختلفی از جمله فالکن مارک و شاخص سازمان ملل در بررسی ردپای آب استفاده شد. نتایج محاسبات ردپای آب نشان داد که مقدار ردپای کل در سال های 1380، 1390 و 1395 به ترتیب 94311.2، 104689.6 و 120483.3 میلیون مترمکعب بوده است. در بین بخش های کشاورزی، صنعت و خدمات، بخش کشاورزی با مقادیر ردپای 88579.3، 98243.6 و 114457.4 میلیون مترمکعب برای سال های 1380، 1390 و 1395 بیشترین ردپای آب را داشته است. مقایسه مقادیر ردپای آب نشان داد که مقدار ردپای وارداتی از ردپای صادراتی بیشتر بوده است. بررسی تجارت آب مجازی کشور نشان داد ایران به دلیل واردات محصولات بیشتر از صادرات، طی سال های 1380 و1395 واردکننده خالص آب مجازی بوده است. شاخص فالکن مارک برای سال های 1380، 1390 و 1395 به ترتیب 2678، 1945 و 1697.81 مترمکعب محاسبه شد. در نهایت شاخص سازمان ملل برای سال های مذکور به ترتیب 53.8، 71.6 و 88.8 درصد محاسبه شد، که نشان از ورود ایران به بحران آبی دارد. در حالت کلی نتایج حاکی از وضعیت نگران کننده کشور از لحاظ آب و منابع آبی است و نیاز است تا مدیران و مسئولان بخش های مختلف کشور اهتمام کامل در توجه به این مهم داشته باشند.

comparison of water footprint trends in different products of iran's economic sectors

introductionwater resource constraints have transformed the economic evaluation of water productivity into a critical issue. among various metrics, the water footprint (wf) has emerged as one of the most important indicators for assessing water use efficiency from an economic perspective. this study examines changes in iran's water footprint across agricultural, industrial, and service sectors for the years 2001, 2011, and 2016 using an input output model. given iran's arid and semi arid climate coupled with unsustainable water consumption patterns, analyzing wf trends is essential for future policymaking. results indicate that iran's total wf increased from 94,311.2 million m³ in 2001 to 120,483.3 million m³ in 2016, with the agricultural sector accounting for over 90% of the national wf. analysis of virtual water trade reveals iran's status as a net virtual water importer due to higher imports than exports during this period. the falkenmark index declined from 2,678 m³/capita (2001) to 1,697 m³/capita (2016), while the un water stress index increased from 53.8% to 88.8%, signaling severe water crisis conditions. these findings underscore the urgent need for sustainable water resource management strategies.materials and methodsthis research employed symmetric input output tables (product by product) for 2001, 2011, and 2016 obtained from the iranian statistical center. sectoral water consumption data for agriculture, industry, and services were collected from the iran water resources management company and the economic accounts office. a top down input output approach was adopted for wf calculation, where direct water coefficients were derived by dividing sectoral water consumption by production output. the total water requirement matrix was then obtained by multiplying the diagonalized direct water coefficient matrix with the leontief inverse matrix. internal wf was calculated by multiplying the water multiplier matrix with the final demand matrix. for imported wf estimation, the study assumed that production technologies of imports were identical to domestic production. virtual water trade balance was determined by subtracting exported virtual water from imported virtual water. additionally, two water scarcity indicators were applied: the falkenmark indicator (renewable water resources per capita) and the un water stress index (annual withdrawals as percentage of renewable resources). study limitations included unavailability of post2016 input output tables and inconsistencies in water consumption data recording across different institutions.results and discussionsectoral wf analysis revealed that agriculture dominated iran's water consumption, maintaining approximately 94% share in 2001 and 95% in 2016. the agricultural wf grew from 88,579.3 million m³ (2001) to 114,457.4 million m³ (2016), indicating substantial water use intensification. within industry, chemical and pharmaceutical production accounted for the highest wf, while oil and gas sectors showed declining wf trends. the services sector exhibited maximum wf in electricity, water, and gas utilities. virtual water trade analysis confirmed iran's persistent net importer status throughout the study period, with the trade deficit expanding from 698 million m³ (2001) to 7,127.8 million m³ (2016), reflecting growing external water dependence. agricultural products like wheat and barley constituted major virtual water imports, while fish and fishery products occasionally featured as exports. the falkenmark index demonstrated consistent decline from 2,678 m³/capita (2001) to 1,697 m³/capita (2016), indicating critical reduction in renewable water availability per capita. concurrently, the un water stress index escalated from 53.8% to 88.8%, confirming severe water crisis conditions according to international benchmarks. comparative analysis with previous studies revealed discrepancies with tafazzoli (2013) which reported iran as net virtual water exporter in 2006, potentially attributable to methodological differences or shifting trade patterns. however, the findings aligned with zarei (2016) which identified iran as net importer in 2011.conclusionthe study findings paint a concerning picture of iran's water resource status. the simultaneous growth of national wf and decline of renewable water resources necessitates immediate action toward sustainable water management. the agricultural sector, as the dominant water consumer, requires fundamental reforms in cropping patterns and irrigation efficiency. expanding virtual water imports, while temporarily alleviating domestic pressure, may threaten long term water and food security by increasing external dependencies. water productivity improvements in industrial and service sectors must become policy priorities. the critical water scarcity status confirmed by both falkenmark and un indicators demands transformative changes in water governance approaches. policy recommendations include: (1) implementing water saving agricultural technologies and crop optimization, (2) promoting water efficient industrial processes, (3) developing sustainable trade policies that consider virtual water flows, and (4) establishing integrated water monitoring systems across all sectors to enhance data reliability for future analyses. this research demonstrates that without urgent interventions, iran will face severe challenges in maintaining water security. the findings provide crucial evidence for policymakers to develop comprehensive strategies addressing both supply side and demand side water management, with particular emphasis on the water food energy nexus in national development planning.