Nowadays, the increased use of International Watercourses for non-navigational purposes, such as agricultural, industrial, and trade use has put them in the spotlight. Meanwhile, global weather change, droughts, excessive uses of water resources, scarcity of water resources, and population growth have increased the conflicts over International waterways. One of the common principles in public International law is the principle of cooperation between the countries emphasized in the UN charter and a number of bilateral and multilateral agreements, including the 1977 Convention on the Law of Non-navigational Uses of International Watercourses. In recent years debates between Iran and Iraq over the use of International waters have intensified and it seems without cooperation between both countries these debates cannot be resolved. Therefore, the principle of cooperation regarding International Watercourses has been chosen as the subject of this research. This research has applied descriptive and analytic methodology. The purpose of this study is to show to what extent the principle of cooperation is reflected or indeed implemented in the International and bilateral agreements on Watercourses between Iran and Iraq.

In the view of geopolitics and International law, International Watercourses are very significant in International relations. So, the environment of these Watercourses should be protected. Using available resources at International Watercourses and protecting their environment are important issues of modern International law. Watercourses including lakes, rivers, and International straits are located among two or more countries. International straits are important components of International Watercourses which are basically used for commercial and military shipping not only by coastal states but other countries. Therefore, legal status of the Strait of Hormuz as an International strait is affected by the law of International Watercourses. So, in this paper, authors have studied on environmental protection of International Watercourses by emphasis on the Strait of Hormuz. By regard to strategic importance of the Strait of Hormuz for Iran, and its geopolitical role, in first part of this document, Possibility of blocking the Strait of Hormuz has been deliberated, and in second part, it has discussed about environmental protection of the Strait of Hormuz by considering soft and hard law.

International Water Law like other legal branches is composed of a set of substantive and procedural principles. In fact, International legal community has established different legal principles in order to solve the problem of allocation and distribution of International Watercourses. Two of the most important of these principles that are widely accepted in International law, the practice of governments, the works of legal scholars, case law, and jurisprudence, are equitable and reasonable principles and no-harm principle. The prevailing view is that the principle of equitable and reasonable use is given priority and the principle of noharm is in subordinate to this principle. A deeper look at the articles of the 1997 Convention and other legal documents in this field and judicial judgments shows that the principle of no-harm is an independent principle in International water law that there is no conflict between this principle and the principle of equitable and reasonable.

Phenomenon of urban flooding was brought by the physical expansion of cities in the world that makes severe injuries on the bodies of large cities in the developed developing countries.Bad memories of floods in Tehran in 1366 in Glabdrh and during1373- 74 in Kan basin express Tehran vulnerability against floods. Tehran is located on the southern in the Alborz and Basins of Jajrud, Ken and Karaj and several small basins.Inharmonious development in Tehran, lack of privacy of natural hydrographic network, land leveling and construction, disorder of Drainage system due to Occupation of watercourse, Implementation of some projects such as the West watercourse and drained tunnels in Tehran central and Construction of several highways along the East - West which they have broken the major drainage have been caused floods network in Tehran increasingly Being faced with unpredictable urban floods. This research has been carried out pattern analysis of watercourse as the most important factor in spatial distribution of floods. Data used in this study have been included 10 meters elevation data, ETM+ images, landuse data, watercourse network and field research. Methodology in this study was compared functions. The results showed that Natural and artificial channels in the East and over 130 kilometers northeast of Tehran, including, Velenjak, Darband, Maghsoudbaik, Sohanak, Kashanak, Mansarieh, Darabad, Sorkhehesar, Mobarak Abad, Ghasre Firozeh, Khashayar, Tehran Pars and some small basins, over 50 percent of Watercourses are in conformity with the natural drainage of Tehran. Natural and artificial channels in the West and northwest Tehran over 140 km including Darakeh, Farahzad, Hesarak, Kan, Cheetgar and the West channels over 65 percent are the lack of harmony with the natural drainage of Tehran. Network of central Tehran, including tunnels of Navab, Khayyam, shahrdari and 17 Shahrivar which is covered, but they are not able to gather runoff. Therefore, organizing the watercourse network according to the metropolitan Tehran environmental is Iran's strategy to control flooding in the capital.

In recent decades, population growth, urban sprawl, urban environmental changes, and related issues are one of the significant issues in proper planning to manage the urban environment. One of the issues in urban development is the occurrence of floods and flooding due to heavy rains. In this research, flood modeling was studied in Mashhad Zarkash Watercourses. The amount of rainfall for the return period of 10, 25, 50, 100, and 200 years were extracted by CumFreq software using the maximum 24-hour rainfall statistics of three rain gauge stations closer to the Zarkesh, Jagharq, Sar-e-Asyab, and Torqabeh Watercourses basins during the statistical years 1364 to 1390. The peak discharge was calculated using the US Soil Protection Organization (SCS) rainfall-runoff method. Zarkesh watercourse is located on the outskirts of Mashhad. River and flood flow modeling was performed using Arc GIS, HEC-GEORAS, and HEC-RAS software in two conditions including structure (bridge) and no structure. Due to urban marginalization, urban development and land use change have greatly expanded in this region. The results of flood simulation showed that flood levels with a return period of 50 years increased by 50000 m2 equal to 22% in the presence of a structure compared to the state without a structure. The results of this research show that the construction of bridges on the river, the roughness coefficient by land use change, and the number of curves due to land permeability changes are effective in the flood zone.

Although Jack Snyder is a defensive neo-realist, he has kept himself faithful to Waltz's structuralism; his big difference in this work is in his attention to the factors that were compared to the level of the International system and are placed at the reductionist levels. By combining the mentioned levels, the author presents a clearer picture of some countries' causes of war and unjustified expansionism. Among the structures mentioned in Snyder's work, we can mention the differences in the political systems of nation-states and the impact of these differences on their distinct foreign policy behaviors. The author searches for many roots of expansionist decisions in the psychological dimension and examines the possible causes of expansionist thinking in structural impositions, which, from his point of view, are not the primary cause in most cases. In the end, it is important to mention that the expansionist groups of a country often use these impositions to move towards unbridled expansionism with the use of propaganda techniques and exaggerating external risks to mobilize political resources.

IntroductionAfghanistan is a  country that shares four waterways (Hirmand, Kabul, Harirud, Amu) with neighboring countries. These Watercourses are an important source of water supply in Afghanistan and its neighboring countries. Except for the Hirmand River which has the 1973 treaty as its governing source of legal regulation, the other three water basins of Afghanistan do not have a treaty exploitation system and are considered subject to the customary rules. Therefore, any use of these waterways is only possible within the framework of the customary rules of International law of the sea. Due to various historical reasons, Afghanistan has not had the opportunity to avail itself of these Watercourses. In the last few years, this country has designed and implemented programs to manage and use its water resources. Many of these actions were faced with protests from Afghanistan's neighboring countries. These countries have considered the actions taken by Afghanistan to be in conflict with International law, especially the customary law governing International waterways. According to the practice of states, and the opinions of International judicial and non-judicial institutions, currently, there are rules such as reasonable and equitable utilization, the prohibition of incurring serious harm to other countries, and the responsibility to cooperate, which underly the basic and customary rules of International law of the sea. The customary characteristic makes states legally obliged to comply with these rules regardless of their membership in International treaties. States’ violation of customary obligations will result in International liability. Without a doubt, Afghanistan, as a member of the International community, will not be exempt from this rule. Research Questions The present research examines the status of the customary obligations regarding the non-navigational use of International waterways in the legal system and the practical practice of the Afghan government. The research seeks to answer these questions: What is the approach of Afghanistan's legal system towards the International customary rules of the sea and do the domestic laws require the government to comply with these obligations or not? What is the practical practice of the government in this case and to what extent are Afghanistan's actions consistent with the International customary rules? Research Background As an important source of life and livelihood, the subject of waterways has been of interest to humans forever. The greatest human civilizations are built next to water sources. With the formation of nation-states, the discussion of International waterways and their exploitation by countries was raised. In this regard, many researches have been conducted and published by scholars on how to regulate the use of International Watercourses around the world.Although such research was initially centered around the use of navigation, with the increase in population, the climate changes, and the pollution of water resources, non-navigational exploitation and their related topics also attracted the attention of scholars. Regarding the International Watercourses of Afghanistan, many researches have been published by different authors both inside and outside of Afghanistan, in different languages.The common denominator of all of these efforts is the focus on contractual obligations, management, and the protection of water resources. Therefore, an important i.e., International customary obligations of Afghanistan and its practice and performance in this area has been neglected. However, some authors have mentioned some of these obligations in their research. For example, we can refer to works such as the research  of Mr. Jamshid Momtaz titled “The legal system of the middle East Watercourses”, “Ali Raghanabi: The legal principles governing the International rivers, with an emphasis on the Hirmand River”, “Nusratullah Afzali: The principles governing the International Watercourses with an emphasis on the Harirud river”, and “Mrs. Sara Naqshband: International Practices in the Settlement of International River Disputes”. Within Afghanistan, in the last few years, research has been carried out in the field of Transboundary Rivers. The major parts of these research papers have been carried out by the Doran Institute, which is a private research institute. This research center has so far published two articles in this area (Amu and Kabul) and besides these, publishes a journal about the waters of Afghanistan, the first issue of which was published in 2015. This research focuses on the capacities of the mentioned areas, the capabilities and challenges of their use, and the climate risks that threaten these waters; it briefly refers to the legal aspects of using these waters. however, it has not been specifically and comprehensively addressed. DiscussionArticle 7 of Afghanistan’s Constitution recognizes the government’s responsibility to comply with the United Nations Charter, the Universal Declaration of Human Rights, and other treaties that Afghanistan has accepted, but it does not make any reference to International customary obligations. Of course, this does not mean that Afghanistan does not accept customary International obligations. the obligation to comply with the UN Charter (based on Articles 1 and 2 and other principles of the Charter) is not limited to treaties, and includes obeying all binding sources of International law. The constitution, especially its seventh article, has stated the obligations that need to be approved by the parliament (National Council) and approved by the president. Customary International obligations are usually entered into national systems through automatically and informally and do not require a special process for ratification andapproval. The study of Afghanistan's legal practice, including the study of the past constitutions (1980 and 1987), in which, in addition to treaties, Afghanistan's obligations to other accepted principles and rules of International law are set out, supports this claim.This is why the Afghanistan transboundary water policy, which was approved by the Council of Ministers in 2015, mentions Afghanistan's responsibility to comply with the International rules and regulations in the operation of transboundary waters in its sixth chapter. International rules and regulations include contractual and customary rules.The practice of the Afghan government in the exploitation of common waterways is in line with its responsibility to act by these rules. The signing of a treaty with Iran (in 1973) and an agreement with the Soviet Union in the field of utilization of the Amu River (in 1958 and 1964) indicates that this country considers itself bound to International obligations in this field. Conclusion The Afghan constitution is silent on its International customary obligations. nevertheless, the emphasis on compliance with the United Nations Charter in its seventh chapter also includes complying with the customary rules. The legal and practical practice of the Afghan government shows that this country considers itself obliged to comply with these obligations not only as a  member of the International community; but also according to its domestic laws. However, examining the degree of compliance of this country's actions in the use of International waterways with its International obligations requires examining all the related factors. Without access to the relevant information, it would be very difficult to consider these actions in violation of these obligations. However, the principle of responsibility to cooperate obliges the Afghan government to take appropriate measures to deal with these protests within the framework of International law.

Background: International law has undergone tremendous changes in recent decades. One of these developments is the humanization process of International law, which has been identified as human rights in the International arena. Human rights have a universal nature and function and are not limited to time and place. Therefore, the ethics of human rights is universal. This category of ethics should be considered in the seas as it is considered on land. Human ethics dictates that all people in the sea have their human rights without any discrimination. There is no reason to deny and disobey the ethics of human rights at sea. Therefore, the present study was formed with the aim of investigating the ethics of human rights in the marine environment. Conclusion: One of the most important areas where the concept of human rights ethics can be applied is the environment of seas and oceans. Among the important cases that can be mentioned in this context are: drug and psychotropic drug trafficking, piracy, maritime terrorism, marine environment, slave trade, common heritage of humanity, immigration and asylum, rights of seafarers and forced labour on ships and vessels and so on. The lack of a comprehensive human rights treaty that covers all the above-mentioned issues in the field of seas is well felt, and there is room for effective measures to be taken in this regard by the relevant International institutions, headed by the United Nations.