A B S T R A C T
In light of escalating environmental challenges and climate change, the establishment of a network of monitoring stations across basins has emerged as a fundamental requirement for optimal water resource management and natural hazard mitigation. These stations facilitate the collection of precise, real-time data, enabling the analysis of hydrological trends, the assessment of flood hazards, and the development of strategic plans to reduce vulnerability. Accordingly, this study aims to identify optimal locations for monitoring stations within the Qaleh Chai basin in East Azerbaijan Province, Iran. To achieve this objective, ten key parameters influencing optimal site selection were considered: elevation, slope, aspect, distance from streams, distance from villages, distance from urban areas, distance from roads, distance from faults, lithology, and land use. The CRITIC multi-criteria decision-making method was employed to determine the weight of each parameter. The weighting results revealed that proximity to rivers, roads, villages, and urban centers played a pivotal role in site selection. Using ArcGIS software, a final suitability map was generated by integrating the weighted parameters with their respective spatial layers. The map was classified into five categories: highly suitable, suitable, moderately suitable, unsuitable, and highly unsuitable for monitoring station installation. The findings indicated that areas near the watershed outlet—particularly low-gradient plains adjacent to rivers and major roads—were identified as ideal zones.
Extended Abstract
Introduction
One key approach to achieving sustainable development objectives in watersheds is comprehensive monitoring and oversight of all elements and components within the basin. This approach involves the meticulous examination and assessment of various factors such as water resources, soil, vegetation, and climatic conditions, all of which play a fundamental role in ecological balance and environmental sustainability. By collecting and analyzing precise data on these components, effective, targeted measures can be designed and implemented to manage natural resources sustainably and protect the environment. To accurately monitor these components, it is essential to establish a monitoring station at the most suitable location within the watershed. Therefore, in this study, to identify and determine the most suitable and optimal possible locations for establishing monitoring stations in the Qaleh-Chay basin—considering climatic, geological, geomorphological, vegetation, and land-use factors—the CRITIC weighting method, a widely used approach in multi-criteria decision-making, has been employed. The application of such scientific and systematic methods can pave the way for integrated and comprehensive management of the studied basin. By considering various criteria and systematically integrating them, this approach enables authorities and planners to make more optimal decisions.
 
Methodology
The research focuses on the Qaleh-Chai River Basin. The geomorphological and climatic conditions governing the Qaleh Chai watershed have resulted in significant spatial and temporal fluctuations in the hydrological behavior of the Qaleh Chai River. These characteristics have endowed the study area with a high potential for flood occurrence. For instance, the recorded maximum 24-hour rainfall of 50 mm and peak discharges exceeding 120 m3 per second underscore this watershed's considerable capacity to generate severe floods. This situation arises from the combination of specific geomorphological and climatic factors in the region, which collectively lead to hydrological instability and an elevated risk of flooding. Nearly all settlements in the region are situated along the basin's main watercourses, particularly the Qaleh-Chai River, thereby substantially increasing the vulnerability of local communities. Consequently, implementing comprehensive flood management and control measures in this basin is critical. The highest point in the basin is Meydan-Dagh Mountain at 3,405 meters above sea level, while the lowest point in the downstream section is at 1,292 meters. This study adopts an applied research approach and employs a descriptive-analytical methodology. In the first phase, a comprehensive literature review and expert consultations were conducted to identify key indicators and influential parameters for selecting optimal monitoring station locations. The parameters used include elevation, slope, slope aspect, distance from stream, distance from village, distance from city, distance from road, distance from fault, lithology, and land use.
In this study, slope, aspect, and elevation class maps were generated from a Digital Elevation Model (DEM) with a 12.5-meter spatial resolution. All processing and map production stages were conducted within the ArcGIS software environment. Using Landsat 8 imagery, a land-use map of the study area was prepared, encompassing five classes as water bodies, orchards, agricultural lands, urban and rural settlements, and rangelands. For the preparation of the lithology map and the identification of faults within the study basin, 1:100,000-scale geological maps from the Geological Survey and Mineral Exploration of Iran—specifically the Ajabshir and Osku sheets—were employed. In this research, proximity maps of distances to streams, villages, cities, roads, and faults were generated using the Euclidean Distance tool in ArcGIS. These maps were classified into five distinct categories. The measured distances (including distance from rivers, villages, cities, roads, and faults) are expressed in meters. Furthermore, the drainage network of the region was extracted using the DEM layer. The Google Earth system was utilized to map the spatial locations of villages. After identifying and geolocating the villages, the collected data were imported into ArcGIS to create a comprehensive database. For extracting the spatial locations of roads within the study area, data from the OpenStreetMap website were used. Additionally, the city of Ajabshir's location within the region was determined using Google Earth and subsequently imported into ArcGIS.
 
Results and discussion
The weighting of research criteria was determined using the CRITIC method. This approach assigns each parameter an appropriate weight based on its degree of influence on the study's subject. Given that identifying a suitable location for establishing a monitoring station in the Qaleh-Chai watershed is the primary objective of this research, the key criteria for this process were considered determining factors. Accordingly, the criteria of distance from watercourses, roads, and rural and urban settlements received the highest weights due to their critical role in selecting the optimal site. Other criteria were assigned lower weights in accordance with their reduced influence on the site selection process. The parameter weighting results revealed that four key criteria—distance from river, distance from road, distance from village, and distance from city—played a significant role in determining optimal locations for monitoring stations, with respective weight coefficients of 0.134, 0.127, 0.114, and 0.101. The final suitability map was generated in ArcGIS by multiplying each parameter’s weight by its corresponding spatial layer. This map was classified into five distinct zones based on suitability levels: highly suitable, suitable, moderately suitable, unsuitable, and highly unsuitable for monitoring station placement. Spatial analysis indicated that the most optimal zones were predominantly located in downstream areas of the basin, particularly in low-slope plains adjacent to major rivers and primary roads. These regions were identified as ideal due to their favorable accessibility to water resources and transportation networks, while maintaining an optimal distance from urban and rural settlements. These expansive areas not only benefit from optimal topographic conditions and favorable locations but also enable the simultaneous monitoring of multiple hydrological parameters, thereby significantly reducing operational and maintenance costs.
 
Conclusion
The Qaleh-Chai Basin, covering 482 square kilometers, requires a network of monitoring stations to collect precise hydrological data due to its unique geographic location and diverse topography. The identified areas, considered ideal zones, are primarily located at the basin's outlet, gently sloping plains adjacent to the river, and along main roads. These regions are given high priority due to their easy accessibility and the potential for simultaneous monitoring of multiple parameters. This study reveals that combining multi-criteria decision-making approaches with Geographic Information Systems (GIS) can provide an efficient tool for environmental planning. The findings of this study are of substantial importance from geographical, geomorphological, and natural hazard management perspectives, particularly regarding floods. Monitoring stations situated within optimized zones can provide the essential data required for flood forecasting and management. These data encompass changes in discharge, sediment load, water quality, and vegetative cover, all of which are critical for designing early warning systems and planning flood risk mitigation strategies. The findings of this research can serve as a model for other basins with similar conditions. Finally, for future studies, the use of emerging technologies such as remote sensing and artificial intelligence is recommended to enhance the accuracy and spatial coverage of monitoring data.
 
Funding
There is no funding.
 
Authors’ Contribution
Authors contributed equally to the conceptualization and writing of the article. All of the authors approved thecontent of the manuscript and agreed on all aspects of the work declaration of competing interest none.
 
Conflict of Interest
Authors declared no conflict of interest.
 
Acknowledgments
We are grateful to all the scientific consultants of this paper.