Abstarct: The transboundary Aras River is an important river in the northwest of the country, whose basin includes, in addition to Iran, Turkey, Armenia, and Azerbaijan. Many water development projects are on the agenda in this basin, which can affect the quantity of water resources in this basin, which is especially important for Iran, which is located downstream. For this purpose, the SWAT model has been used in this study along with information from global databaxses. Obviously, in addressing the above development challenges, the history of basin interactions must be taken into account. Especially for a basin whose history dates back to the 1920s. This important point shapes the innovation of this study from a "hydropolitical" perspective, and both engineering and political capacities have been used in the analyses conducted. In order to achieve the aforementioned goals, first, historical records of water interactions in the Aras Basin from various sources such as IWED databaxses were organized in the form of a TWINS matrix to better explain past events - especially from the perspective of simultaneous conditions of cooperation and conflict. The BAR index was also used to quantify the intensity of cooperation and conflict. Next, the drivers that have been effective in the formation of water events in the basin (including climatic and development factors) were simulated using the SWAT model to examine the prospects for changes in the basin's water resources. Given the transboundary nature of the basin and the limitations of available observational data, a large part of the required information was obtained from the NCEP CSFR and CRU global climate databaxses, reference reports, and Landsat satellite images. The research results can be presented in two parts. In the first part, the historical review of water events showed that most of the events in the period before 1921 were around border issues, which led to the stabilization of borders to some extent, but this did not mean that complete peace was achieved. The review of water events after 1920 can be divided into four sub-periods: 1) 1926 to 1990; 2) 1991 to 1994; 3) 1995 to 2017 and sub-period 4) 2018 to 2021. The average BAR scale for each of these sub-periods was +2.76, -1.36, +1.92 and -0.03, respectively, which indicates a change in the basin space from cooperation to conflict, and the main reason for this was border events. Despite the worrying border challenges, the basin benefits from several agreements that have had positive effects on maintaining water cooperation. The modeling results also show the ability of SWAT to simulate the flow discharge of the transboundary Aras basin under various development measures and the proper functioning of the CRU baxse. In this regard, the R2 coefficient at the two hydrological stations of Karakurt and Surmalu for the calibration period was 0.65 and 0.71, respectively, and the NS coefficient was 0.62 and 0.69. The area under cultivation of aquatic products with satellite images during the two periods 1983 to 2008 and 2009 to 2018 was estimated to be 140 thousand and 230 thousand hectares, respectively. Applying these environmental changes to the calibrated SWAT model for the basin in three scenarios shows that in the historical scenario, the annual runoff volume of the Upper Aras River has decreased from 2605 to 2155 million cubic meters, which has caused an 18% decrease in river discharge. Running the model in the scenario of expanding the cultivated area shows a further decrease in flow and a change in its monthly regime, such that in May its average decreases by 26%. According to the results, the average agricultural water consumption in the western and eastern parts of the basin located in Erzurum and Kars provinces was estimated to be 494 and 458 mm/ha, respectively, which can be a basis for assessing the impact of future developments in the basin. The assessment of the consequences of climate change showed that the annual discharge of the Aras Border River in the pessimistic scenario of the GFDL-ESM2M model (2020-2050) at the Karakurt and Surmalu stations will decrease by about 13% and 11%, respectively. However, the main changes are related to the change in the monthly flow regime of the river. The results of the comparison between the annual flow figures and the intensity of cooperation/conflict show that in the high-water years, the frequency of events that determined cooperation in the basin was higher. However, the situation may change in the future and the continuation of these reductions.