Mehrnoosh Ghadimi

Reliable assessments of dam stability require the continuous acquisition and interpretation of deformation data, as monitoring technologies provide essential information for evaluating structural behavior. Surface displacement measurements are particularly valuable for identifying instability within the dam embankment and adjacent slopes. While terrestrial surveying networks can provide accurate point-based observations, they are often time-consuming and costly to maintain. Satellite radar interferometry (InSAR) offers a complementary, cost-effective means of monitoring surface displacement with wide spatial coverage; however, careful analysis is required to avoid misinterpreting superficial motions of riprap and cover materials as true dam settlement. In this study, we use multi-platform SAR datasets, including Sentinel-1A (2014–2019) and high-resolution TerraSAR-X (2018), to investigate the deformation behavior of the Taleqan Dam. We compare LOS displacement derived from InSAR with independent measurements from a terrestrial surveying network spanning the same period. TerraSAR-X data indicate up to ~20 mm of LOS displacement over three months (May–August 2018), and the displacement pattern is consistent with the Sentinel-1 time series. Despite lower spatial resolutions, Sentinel-1 provided dense, temporally continuous coverage, with LOS velocities reaching ~4 mm/yr on the downstream slope. The combined datasets demonstrate that the observed deformation predominantly reflects the ongoing lateral movement of downstream riprap materials rather than the vertical settlement of the dam’s core. These results highlight both the utility of InSAR for long-term dam monitoring and the importance of integrating multi-sensor observations to ensure accurate interpretations of dam deformation signals.

Karst groundwaters are vulnerable and essential resources that require comprehensive management for protection and preservation. For this purpose, awareness of effective factors are required for the development of karst water resources and their quality management. Identifying the spatial distribution of springs in karst settings is important for a better understanding of groundwater flow because springs are the terminal sites of karst flow networks which are understudied. This study aims to identify the location of karst spring occurrence with an emphasis on geomorphic factors using the Analytical Hierarchy Process (AHP) and Logistic Regression (LR) model. As the case studies in this research, the Lordegan and Shahrekord karst basins located in Iran’s Zagros Mountains were selected. Nine factors influencing spring occurrence are considered and classified into four major groups: geological layer (lithology and distance from fault), hydrology layer (distance from river and drainage density), geomorphological layer (slope, aspect, elevation, and plan curvature), and anthropogenic layer (land use/land cover). The potential map of karst groundwater spring weighed by AHP was classified into five classes (very low, low, moderate, high, and very high) and both basins were in very high to moderate class. The geological layer (i.e., lithology and distance from faults) was the most significant geomorphological factor in the Lordegan basin, with the weight of 56.3%, whereas the topographical layer (i.e., slope, aspect, elevation, and curvature) was in the Shahrekord basin, with the weight of 38.4%. Due to the high-altitude of the studied basins (1944 to 3297 m), the land use/land cover layer had the lowest weight. According to the AHP results, 76.9% of the springs in the Lordegan basin and 60% in the Shahrekord basin are in the very high class spring groundwater potential zone. The LR model was also used to simulate the appearance of springs. The Relative Operating Characteristics (ROC) of the LR model in the Lordegan and Shahrekord basins were 0.9 and 0.85, respectively. Also, the LR results show that 38.4% of the springs in the Lordegan basin and 60% of the springs in the Shahrekord basin are in the very high class spring groundwater potential zone.

Dam stability is one of the most essential geotechnical engineering challenges. Studying the structural behavior of dams during their useful life is an essential component of their safety. Terrestrial surveying network approaches are typically expensive and time-consuming. Over the last decade, the interferometric synthetic aperture radar (InSAR) method has been widely used to monitor millimeter displacements in dam crests. This research investigates the structural monitoring of the Lar Dam in Iran, using InSAR and the terrestrial surveying network technique to identify the possible failure risk of the dam. Sentinel-1A images taken from 5 February 2015 to 30 September 2019 and TerraSAR-X (09.05.2018 to 16.08.2018) images were analyzed to investigate the dam’s behavior. The InSAR results were compared with those of the terrestrial surveying network for the period of 1992 to 2019. The Sentinel-1 results implied that the dam on the left side moved over 8 mm/yr. However, the pillars to the left abutment indicated an uplift, which is consistent with the TerraSAR-X results. Also, the TerraSAR-X data indicated an 8 mm displacement over a three-month period. The terrestrial surveying showed that the largest uplift was 19.68 mm at the TB4 point on the left side and upstream of the body, while this amount was 10 mm in the interferometry analysis for the period of 2015–2020. The subsidence rate increased from the middle part toward the left abutment. The geological observations made during the ninth stage of the terrestrial surveying network indicate that there was horizontal and vertical movement over time, from 1992 to 2019. However, the results of the InSAR processing in the crown were similar to those of the terrestrial surveying network. Although different comparisons were used for the measurements, the difference in the displacement rates was reasonable, but all three methods showed the same trend in terms of uplift and displacement.

Nanomaterials, i.e., those materials which have at least one dimension in the 1–100 nm size range, have produced a new generation of technologies for water purification. This includes nanosized adsorbents, nanomembranes, photocatalysts, etc. On the other hand, their uncontrolled release can potentially endanger biota in various environmental domains such as soil and water systems. In this review, we point out the opportunities created by the use of nanomaterials for water remediation and also the adverse effects of such small potential pollutants on the environment. While there is still a large need to further identify the potential hazards of nanomaterials through extensive lab or even field studies, an overview on the current knowledge about the pros and cons of such systems should be helpful for their better implementation.