Kaloutaks are a geomorphological forms of arid and semi-arid regions around the world. These features are extensive and varied in Iran, resulting from the erosion of fluvial and lake sediments of the Quaternary. Kaloutaks are mostly extended over the Eastern and Southeastern Iran and have unique features. Meanwhile, the kaloutaks in the playa of Sistan Hamun are considerably extended. The studied area includes part of the kaloutaks in this region. The main objective of this study was to examine and find the origin of sediments deposited in the old delta of Hirmand River, the main area for the extension of kaloutaks. To this end, five sediment samples were specifically taken from the area and examined using XRD and XRF laboratory analysis methods. Results showed that sediments such as quartz, aluminum, calcium, and other evaporates have the highest percentage in kaloutaks. Moreover, based on the elements obtained from the tests and examining the geographical maps of Iran and Afghanistan, it can be concluded that these sediments have both an internal and external origin. Eroded and sedimented formations of flysch in the Eastern Iran confirm the internal origin of sediments, and the presence of quartz, aluminum, calcite, dolomite, muscovite, albite, and other minerals indicate the external origin of these sediments, transferred by Hirmand River and sedimented in the playa of the Hamun. Based on results, the sediments of the old delta of Hirmand River have provided the best condition for the erosion and formation of kaloutaks in this region due to pedological features and climatic factors.

Due to its dry geographical condition, Iran is among those countries which always face shortages of water. Also, it has shared water resources with some neighboring countries. Hirmand River originates from the mountains of Afghanistan and has much economic importance for Iran. By building dams on the path of the River and forming illegal channels and diverting the River from its main path, Afghanistan has dried the international lake of Hamoun. In 1973, two countries signed an agreement about the division and use of Hirmand River. But Afghanistan use drought and not being provided some terms of the agreement as the excuse to evade implementation of thetreaty. As the result of the United Nation’ attempts, some rules have been established, so that if there was no agreement among parties, they can ensure the interests of countries. These rules are established on the basis of fair exploitation and cooperation of parties. Even if there was not any binding agreements between Iran and Afghanistan, according to international principles and rules, Iran possesses the fair rights in use of Hirmand River and Afghanistan cannot deprive Iran of its own rights by invoking its sovereign rights.

This research was aimed to investigate Hirmand River morphology alterations through the estimation of suspended loads transported by floods. The sediment samples were collected and suspended loads were estimated. The alterations of sediment load along Sistan reach was investigated, spatially and temporally. The suitable reaches for sedimentation inspected through the high resolution Satellite imageries of Spot-5 (with the spatial resolution of 2. 5-5 m). Through the geo-referencing of aerial photos and satellite images in GIS environment, the changes of River width, meander angel, and sinuosity index were estimated during the last 50 years. The t-student test was employed to assess the changes of River width during time. Results showed that the average suspended sediment load of Sistan River was 32 grL-1 and approximately 7. 3 million tones sediment load entered to the study reach. According to the results, the River width has been changed, significantly. The River width in 2016 has been decreased by 0. 33 of that in 1965 and 73% of the River has no capacity for flow transport and shows a high density of suspended load. This study established that the hydrology parameters (sediment and flood), biologic and slope changes are the main causes of sediment load and the changes of River morphology from a disorganized sinusoidal meanders to limited meanders. During the period of 1965-2016 the pattern of flow changed from meander to the sinusoidal. The average angel of River from 287. 94 changed to 295. 26 degree. The average of sinusoidal index changed from 1. 39 to 1. 18 and the average of flooding bed width from 160. 79 m changed to 41. 32 m in 2016.

Border Rivers, as one of the most important natural terrain, are always the source of many differences in relations between states. The Hirmand River is the main artery of the Hamoon Lake, the borderline between Iran and Afghanistan, which has caused many border controversies between the two countries to this day. Failure of Afghanistan's to adhere to 1973 agreement to provide the water right of the Hirmand River, and hence the land of Hamoon, as a lake that Sistan's life is dependent on, has exacerbated the increasing challenges in the Sistan region. There has been a lot of negotiation between Iran and Afghanistan. Authors intend to answer the question of what are the strategies of diplomacy for providing the water right to the Hirmand River between Iran and Afghanistan. In the framework of game theory, in the first stage, the Hirmand Water Crisis should be considered as an important priority in the field of Iranian policy. Then, in the process of negotiations between Iran and Afghanistan based on diplomacy, the rationality of actors, Afghanistan’ s access to the Chabahar port and the provision of the Hirmand water right as the point of equilibrium and the best option for both countries.

Natural Rivers are constantly changing in terms of dimensions, shape, direction and patterns under the influence of various factors and variables, and the diversion of Rivers is always studied. Features such as River flow trends, network route changes, River network patterns, and communication can be done using satellite imagery. The purpose of this study is to move Hirmand River from Rudbar Afghanistan to Hamoon Sistan with a length of 275 km using Landsat 5, 7 and 8 time series satellite images from 1988 to 2018. The image was taken and analyzed every 5 years, ie 1988, 1993, 1998, 2003, 2008, 2013, 2015 and 2018. GIS and ENVI softwares are the most important tools used in this research that were used to prepare and extract data. The studied River has geometric parameters such as mean and standard deviation, etc. for curvature coefficient, valley length and wavelength have been calculated. The results of this study showed that as we go from 1988 to 2018, the geometric parameters have had an increasing trend due to the changes in the River, and due to the long path of the River, the transverse changes have been divided into 11 intervals until the results be better and more accurately analyzed. The results also show that the average curvature coefficient in 1988 was 1. 5 but in 2018 it reached to 2. 5. This increase indicates many changes in the route and bed of the River. The longitudinal changes and the maze of the Hirmand River in the period 1988 to 2018 have changed a lot and the movement of the River has increased.

Sistan basin is located in an arid zone with less than 60mm precipitation per year. The life of region to be indebted to the Hirmand River and its embranchments inflows that import more than billions cubic meter of water and can support the survive of Hamoon international wetland and the population of the regions. The occurrence of periodic fluctuations in the water inflows and the potential climatic, geomorphologic and hydrologic conditions that expose the surface to wind erosion. In Sistan basin wind blow throughout the year, but during the June to September the wind is more important in respect to direction, frequency and intensity. This wind distinguished as 120days winds and is one of the most famous meso scale wind systems in the northern hemisphere. The effects of these winds can observe in eastern regions of Iran, west and southwest of Afghanistan and northwest of Pakistan. The blow of winds has unavoidable effects on all ecologic, economic and social aspects. High temperature especially during the periods of 120 days winds, lack of precipitation and physical aridity of environment prepar the favorite conditions for winds erosion. These situations accompanying with reduction of soil moisture can increases the possibility of dust storm. In this paper, the relationships between the hydrologic fluctuations and principle components of 120 days winds are studied. The results suggested that the days with visibility less than 2 km, calm conditions and dust conditions in Sistan basin have a significance difference with other regions of Iran and a significant correlation exists between these climatic elements and periodic fluctuations of discharge of Hirmand River, stability of Hamoon lake. These facts are substantiated based on the non-parametric and parametric tests and multivariate regression analysis. By decreasing the water inflow to Sistan basin, the calm conditions significantly decrease, horizontal and vertical visibility reach to minimum and dust storm violently increases and subsequently the environmental problems arising from dust also aggravated.

In the recent decade, in particular in the last years of the 20th century, the challenge of fresh water shortage emerged as a global crisis, and as a very critical theme for international debates. Many countries relay on border Rivers to partial supply of their water demands. In Iran, water of such sources does not posses a significant share of the total water supply at national level. At provincial level, however, there are some regions where transboundary water plays a criticai role. Being one of such provinces, Sistan faces severe damages to agriculture and other vital activities whenever Hirmand River flow declines. The average annual discharge of Hirmand River is about 4.6 billion cubic meters. There are also other Rivers from Afghanistan contributing an additional volume of 2.8 billion cubic meters to Hamoon international wetland. This is while the total contribution of domestic Rivers rarely exceeds 0.6 billion cubic meters. The probable diversion of Hirmand River"s flow to "Goode Zereh," a region in western Afghanistan, without allocating a share to Iran has raised concerns about water management in the region, particularly for Hamoon wetland. The legal regime of Hirmand River has been a major political issue over the last century. Both Iran and Afghanistan recognize the River"s middle bed as their international border. Debates remain, however, on water sharing, utilization in delta zone and other rights on the River.

Introduction: One of the central issues in studies of political geography returns in to governments and their boundaries. Shaping how borders, borders type, borders issues and disputes arising from them are interesting debates in political geography. One of the notable points in the following discussion is the role of phenomenon of colonialism in border drawing. Essentially colonial boundaries combined and separated some societies. Hence imposed and colonial boundaries often involve the problems within their borders to the countries that are parties. The Boundaries River including the natural boundaries is considered that can disrupt economy due to natural areas or because of a shift, makes border problems for surrounding countries. Countries including Iran, which its borders on the one hand by colonialists has been drawn and the other hand is faced with several neighbors. What the studies related to political relations of countries based on River borders (like Hirmand River) is important, the pattern and form of the Rivers that regard to the importance of surface water resources, plays important role in relations between countries.

This study applied the "Transboundary Waters Interaction Nexus (TWINs)" framework to the Hirmand/Helmand River hydropolitical interactions to figure out what can be learned by policy and decision makers by studying the past experiences about transforming conflicts and current ambitions. Analyzing coexisting conflict and cooperation in the Hirmand River by TWINs framework shows that from 1870 until 2020, in most periods, the Hirmand water conflicts have been politicized. But due to the westernization tendency and anti-Iranian sentiment procedure in Afghanistan during 2010-2020, water conflict has been increased and is opportunitized. As a matter of fact, the existence of a bad treaty over shared water, in addition to the international funds and supports from constructing dams in Afghanistan has been given the upper hand to Afghanistan in current negotiations over the Hirmand River Basin. The result of the TWINs framework and past experiences shows that bargaining purely over technical issues in the Hirmand River Basin cannot put water allocation in this basin in a peaceful situation. Therefore, the riparian states should rely on the interdependencies in social-economic, cultural, and security fields in order to create a sustainable and equitable relationship, which ultimately can create common values and norms in riparians’ water interactions. In other words, Iran and Afghanistan's water conflict needs outside the water box's solutions. This also highlights the importance of the depoliticization of Hirmand water interactions for preventing political frictions in hydropolitical relationships.

The ownership and right to exploit the water of the border Rivers is not fully in the possession of a country. This issue has long been the source of political disputes and conflicts and even wars and military operations between governments. The Hirmand border River originates from the Hindu Kush mountains in the west of Kabul, Afghanistan, and finally flows into the Hamun wetland located in the Sistan plain of Iran. This River has been one of the legal issues and disputes between Iran and Afghanistan over the determination of international borders and how to divide water since the signing of the Treaty of Paris in 1857 until now. Hirmand River forms the international border between Iran and Afghanistan in a part of Sistan. The possible changes in the course of this River due to climate fluctuations and human activities in the long term, can be the basis for more political disputes between Iran and Afghanistan over the determination of border boundaries (sovereignty). Therefore, in this study, monitoring the long-term changes of the Hirmand River in the common border area between Iran and Afghanistan is considered as a legal-political necessity. For this purpose, the time series of remote sensing images has been used as a reliable, low-cost and valuable information source.