water resource management

Border watersheds, also known as transboundary watersheds, are areas of land that drain water to a shared water body, such as a river, lake, or sea. These watersheds are particularly important for Iran, providing water resources for agriculture, industry, and human consumption, as well as ecological benefits for biodiversity and climate regulation. One such significant border watershed in Iran is located in the eastern province of Balochistan, bordering Pakistan. It, known as Hamoun Mashekil, is the country's easternmost watershed and annually loses 297 million cubic meters of runoff from Iran to Pakistan. Given the crucial role of border watersheds in Iran, especially in arid regions, there is an urgent need for integrated and participatory water management, along with sustainable and efficient water use within the country. This study investigates the necessity and significance of surface water harvesting systems and their role in preventing water loss in the Esfandak Saravan border watershed. Recognizing the importance of analyzing runoff in border watersheds and the significance of the Esfandak watershed in Saravan City, the study begins by examining the status and trend of discharge at the Esfandak hydrometry station located at the source of the Mashkid River. For this purpose, the non-parametric Mann-Kendall test is employed. Due to the absence of hydrometry stations throughout the watershed, the study utilizes Treaclimate satellite imagery data to assess the runoff status and volume of runoff flowing from Iran to Pakistan. The results indicate a downward (decreasing) trend in discharge at the studied station on both seasonal and annual scales. Notably, this trend is statistically significant at the 95% level for spring and summer seasons on an annual basis. Analysis of a 22-year dataset (2000-2020) reveals that, on average, over 13 million cubic meters of water collected by this watershed flows from Iran to Pakistan via the border river. Without water harvesting structures, watershed management, and aquifer storage, this water is lost through runoff. Therefore, by effectively and efficiently implementing rainwater harvesting systems, the region can achieve its sustainable development goals and enhance its water security.

Water governance in Khuzestan Province, particularly in the Karkheh River Basin, is a complex and multifaceted process involving multiple stakeholders. Adopting a network perspective can provide a systematic and analytical approach to studying this complexity. This research aims to analyze the network of institutional relationships and conflicts in Khuzestan's water governance using a mixed-method approach. To this end, 43 water governance-related institutions were identified as the social boundary of the network using snowball sampling method. To examine institutional relationships, a questionnaire about the intensity of interactions between these institutions was distributed and completed by the respective representatives. These institutions were categorized based on their predominant roles, and social network analysis indicators were measured at the micro level of the network. Additionally, semi-structured interviews were conducted to examine inter-institutional conflicts. Results of the centrality indices indicated that the Provincial Government holds the highest out-degree centrality (90.48%), betweenness centrality (5.1%), and closeness centrality (97.67%), indicated the significant political influence, control power, mediation role, independence, and access to resources and information, thus playing a prominent role in the water governance network. Moreover, the Khuzestan Water and Power Authority with the highest in-degree centrality of 92.86%, held the greatest political authority. The distribution of centrality measures revealed that, despite the significant role of intermediate subgroups in facilitating institutional cooperation, they have low out-degree and betweenness centrality, with asymmetric power distribution. In the conflict network, the Khuzestan Water and Power Authority receives the highest number of conflict ties, while the Environmental Protection Organization has the most conflicts with others. The presence of severe conflicts between the Khuzestan Water and Power Authority, Department of Environment and Agricultural Jihad Organization underscore the need to resolve these conflicts and strengthen coordination in water governance decision-making. Understanding these interactions and conflicts among institutions can assist policymakers in achieving effective water governance

Currently, drought poses a significant threat to food security due to reduced rainfall and increased agricultural demand. Its impact is particularly severe in arid and semi-arid regions, where populations are more vulnerable. Drought affects groundwater systems by initially lowering water supply, followed by a decline in groundwater levels and discharge. Compared to other types of drought, characteristics such as duration, intensity, and frequency alter groundwater systems.

Given the critical need for drought assessment and monitoring, this study investigated drought conditions in 12 areas within the Daranjir Watershed from 2002–2003 to 2017-2018. The watershed spans approximately 50,736.44 km² across Yazd and Kerman provinces, with elevations ranging up to 1,857.90 meters. Highlands cover 58.99% of the area, while plains cover 40.99%. Data on groundwater levels from observation wells were obtained from Iranian Water Resources Research Organization (Tamab) and regional water organizations in Yazd and Kerman provinces. Average monthly groundwater level values were then extracted from maps using inverse distance weighting interpolation in MATLAB. Groundwater drought conditions were subsequently calculated based on the Groundwater Resources Index (GRI) in MATLAB.

The GRI index calculations revealed severe droughts in Daranjir, Bardsir, and Qaryeh al-Arab deserts, with deficits of 81.38, 77.75, and 75.66, respectively. Qaryeh al-Arab experienced the longest drought, spanning 121 months, indicating the area's high intensity and prolonged drought conditions compared to other study areas. Mild droughts were the most frequent after normal drought across all study areas based on GRI index class frequencies.

Due to insufficient and highly variable atmospheric precipitation, drought is inevitable, especially in arid and semi-arid climates. Understanding drought severity and its impact on ecosystems is crucial for effective watershed resource management and optimal resource utilization. Continuous monitoring of groundwater levels due to drought and preparation of a comprehensive atlas for other watersheds in the country are recommended. Additionally, comparing drought conditions using appropriate models is essential. Short and long-term strategies are advised to mitigate this natural phenomenon, such as expanding greenhouse crop cultivation, utilizing drought-resistant crop varieties with high water efficiency, adopting pressurized irrigation systems, and implementing infrastructure projects to enhance groundwater and surface water storage, such as cement dams, reservoirs, and floodwater spreading systems in the study area.

The sudden increase in population growth, followed by the restriction and scarcity of the world's supply of freshwater resources, has created new conditions for countries in the arid and semi-arid belts. To conserve, enhance and make the best use of these valuable resources, several projects have been implemented, including irrigation and drainage, flood control and dam construction. Meanwhile, dams are a very important tool to manage the river water for socio-economic development and also to improve the deteriorated ecological status of the river system and its services. Depending on place and time, dams play both negative and positive roles in environmental flows, with significant environmental costs. According to the results of the documents and reports, the construction of the dam has brought about environmental changes from various aspects of invasion and increase in invasive species to improving access to spawning habitats for migratory fish. The challenge for managers and scientists today is to better understand and manage the consequences of dam decommissioning. For this reason, the purpose of this study is to present the approaches of removing the dam on ecological changes. The results of this research can provide stakeholders in the responsible departments with valuable information about the changes in the behavior of dams on the environmental properties.

This study examines spatial and temporal changes in water resources; including blue and green water resources components, taking into account their changes in four main land use in the Zayandeh-rud basin. The spatial and temporal changes were studied using the semi-distributed hydrological model SWAT (Soil and Water Assessment Tool) by applying the most complete data set developed for the watershed over 20 years and for four different 5-year intervals. Due to the high ability and efficiency of the SWAT model to simulate climatic parameters and surface runoff, the minimum 5-year average of blue water, green water flow, and green water storage at the basin level occurred; in the fourth period 2010-2014 (approx. 15 mm), the second period 2000-2004 (26 mm) and the first period 1995-1999 (30 mm), respectively. On the other hand, the mean values of the blue water component, the green water flow and the green water storage components were estimated to be higher in the western parts of the basin than in the eastern parts. Other findings from this study are the changes of blue water and green water regarding precipitation and land use. For example, the maximum amount of blue water was observed in forests and irrigated agricultural lands, the highest amount of change in green water flow in irrigated agricultural and dry farming lands, and the minimum amount of green water flow in grasslands. Acknowledgment of available water resources, water potentials of an area and critical areas enables comprehensive management of water resources and long-term planning.

The water crisis is rapidly expanding in vast areas of the world. Our country due to be located in dry belt of the earth, the rainfall is less than the global average, the disproportionate distribution of temporal and spatial of rainfall, population growth and per capita demand for water, as well as the consumption of inappropriate water resources is no exception for this reason. According to studies, more than 90% of the country's water is used by the agriculture. A review of water resources management and management approaches, especially in the agriculture, could prevent significant losses of water resources. Water used in different stages of production or an agricultural product called the virtual water that flows through the trade (import and export) of the agricultural product, both nationally and internationally, as a stream of virtual water trade. As the importing country imports virtual water in addition to the food product. Countries like Iran, which are located in arid and semi-arid areas with a dehydration problem, can save water on their water by importing water, or use their own water resources in other areas.

Iran’s location on Earth’s dry belt, and the consequent low precipitation, temporal and spatial changes in precipitation, have placed immense importance to the planning and management of water resources in the country. Thus, modeling can be viewed as one of the methods to investigate flood potential due to land use change. The aim of this study is to determine sites for water harvesting reservoirs for urban landscape applications in Tehran’s first district using the SWMM model; in order to efficiently use water resources, in addition to mitigating damage caused by runoff accumulation downstream and increased pollution. The SWMM model was used to simulate precipitation-runoff. After running the model, 2 events were used to calibrate the model and one event was employed to evaluate the model to confirm its validity and efficiency. The Nash-Sutcliffe coefficient was used to measure efficiency, producing values greater than 0.5 for all three events which confirmed the accuracy of our model. In the next step, factors influencing the possible site of reservoirs were determined using satellite images and GIS software capabilities, which indicated “proximity of the site of accumulation to site of consumption”, “significant volume of runoff”, “site’s suitability for construction”, and “ownership by the city’s municipality” as primary factors. “Distance from raw water supply network”, “existence of a reservoir”, “history of flooding”, “water supply limitations”, and “future development needs” were determined as secondary factors. The results revealed 23 suitable point for runoff storage reservoirs in Tehran’s first district for landscape applications in such a manner that in precipitation events with return periods of two and five years, 3892 and 4880 m3 of runoff pass through the 23 proposed sites. The results point to the district’s potential for development of water harvesting systems which can reduce pressure on subterranean water resources and address some of the challenges faced in the maintenance and extension of urban landscapes through use of unconventional sources of water.

Run off simulation is one of the most important topics in hydrology And its study is based on rainfall- run off models. Several rain fall and run off models have been developed and the most appropriate model should be selected for each catchment. By applying the appropriate model the water consumption will be optimized. The model should be selected for each catchment based on the model abilities and limits. In this study, the performance of two rain fall and runoff models, GR2M and GR4J were compared in Darehtakht Basin in Lorestan Province during 1379 to 1392. The Nash coefficient was used as a decision criteria for comparing two model performances. Nash coefficient for GR4J and GR2M were 42.7 and 65.5, respectively. Results showed that both models can predict the performance of the catchment accurately, but, based on Nash coefficient the GR2M is more accurate than the GR4M.