Abstract. Iran is one of the countries facing high water risk because of its geographical features, climate variations, and uneven distribution of water resources. Iranians have practiced different water management strategies at various periods following the region's geo-climatological features, needs, tools, available resources (surface water and groundwater), political stability, economic power, and socio-cultural characteristics. This study is a brief history of water management in Iran from pre-civilization times to the end of the Islamic Golden Age (1219 AD). This study pointed out geo-climatological features have consistently been crucial intrinsic properties controlling water regime, settlement patterns, and other socioeconomic issues. These factors caused the early agricultural communities to emerge in water-rich regions of northwestern, western, and southwestern Iran. By the 4th Millennium BC, while water access became more difficult as population growth, economic activity, and urbanization progress, water resources' systematic development appeared in west and southwest Iran under the Mesopotamian civilization. However, despite all benefits, Mesopotamian water-based technology and administration could not meet all water demands in Iran's arid regions. For these reasons, qanats were developed in Persia by the First Persian Empire (Achaemenid Empire). No doubt, the Achaemenids (550–330 BC) should be regarded as one of the early civilizations that emerged in a land without sufficient rainfall and major rivers. In this time, idle and marginal lands of Iran and neighboring regions of the Middle East, North Africa, and Central Asia could be cultivated through the spread of qanat technology, enabling large groups of peasants to increase crop yields and incomes. After a period of recession during the Seleucid Empire (312–63 BC) and the Parthian Empire (247 BC–224 AD), water resources development gained momentum in the Sassanid era (224–651). In this period, the progress of urbanization was expeditious. Consciously, water resources development in Khuzestan plains (Shushtar and Dezful) was crucial for agricultural intensification, economic expansion, and civilization development. The Sassanids wisely adapted Greek watermills to the complicated topography, limited water availability, and variable climate of Iran to produce food. Although the Iranians practiced a new era of water governance under the Sassanid rule (224–651 AD), chaotic Iran in the Late Sasanian and Early Islamic Period led to severe weaknesses in water-related sectors. After Islam's arrival, the Muslim rulers turned their attention from fighting to set up an Islamic civilization to break the socioeconomic stagnation. To achieve the goal, they opened their scientific doors to science and technology centers. Despite all efforts made during the 8th–12th century, the lack of creativity and investment in promoting water technologies, prioritizing political considerations over social benefits, occurring wars, and poor water management have induced the Iranians to lose their power in developing water resources. In today's Iran, the past water-related problems have aggravated by uneven climate change, population rise, rapid industrialization, urban development, and unprecedented changes in lifestyle. Undoubtedly, solving these problems and moving towards a better future is not possible without addressing the past.
Development of Irrigation Regime of Limited and Unlimited Water Supply for Satisfactory Rice Yield
