RESUMEN

Lakes are indispensable to ecological balance, supporting biodiversity and human welfare. Despite their importance, lakes around the globe are diminishing at an alarming rate, presenting substantial environmental challenges exacerbated by climate variability and human-induced pressures, such as unsustainable land management and excessive water withdrawals. This study offers an extensive analysis of the desiccation phenomena affecting major lakes on the Iranian plateau, dissecting the complex interplay of contributing factors. We examine meteorological, hydrological, and agricultural drought conditions using indices like SPI, SDI, and SPEI to gain nuanced insights into drought dynamics. This study sheds light on the factors that contribute to the drying up of lakes and quantifies the impact of anthropogenic and climatic drivers on this phenomenon. The findings indicate that the area of all lakes has declined dramatically after the change point, ranging from 51% in the Urmia Lake to an impressive rate (i.e. 100%) in Southern Hamun. Despite the stable rate of meteorological droughts (increasing in temperature by about 1 °C since the 90s and stable precipitation patterns across most basins), the research highlights the ongoing struggle against severe hydrological and agricultural drought conditions. The study delineates the predominant role of anthropogenic activities in the diminishing lake inflows and the consequential drying of the lake, accounting for approximately 100 % in five of the seven lakes.

Asunto(s)

Lagos , Irán , Clima , Humanos , Sequías , Desecación , Cambio Climático , Agricultura

RESUMEN

The Arctic region experiences significant annual hydrologic events, with the spring flood and ice break-up being the most prominent. River ice break-up, in particular, poses high socioeconomic and ecological expenses, including morphological changes and damage to riverine structures. This study aims to investigate the spatiotemporal patterns of river ice in the River Tornionjoki, including the timing of ice break-up at different latitudes. We utilized observation data and remote sensing techniques to track changes in ice patterns overtime on the River Tornionjoki. The study indicates that the ice break-up in the River Tornionjoki basin typically occurs during Apr-Jun based on the reach location in different latitudes; therefore, different stations behave according to their latitudinal location. We observed significant spatial variations in ice break-up timing across the basin, with an earlier break-up in the lower latitudes compared to the upper latitudes. The average ice break-up day in lower latitude stations ranges between 200-205, while in higher latitude stations the average ice break-up day ranges between 215-228.

Asunto(s)

Monitoreo del Ambiente , Ríos , Ríos/química , Monitoreo del Ambiente/métodos , Regiones Árticas , Hielo , Cubierta de Hielo , Hidrología , Estaciones del Año , Tecnología de Sensores Remotos

RESUMEN

Land subsidence, a silent death, occurs due to various factors like significant reduction in groundwater (GW) levels. It is a widespread phenomenon with irreparable consequences on buildings, infrastructures, and, in severe cases, groundwater aquifers. This study aims to assess the impact of river flow on the acceleration and control of land subsidence in an arid and semi-arid region. To achieve this goal, we analyze the interconnection between GW and SW and investigate the role of the Zayandeh-Rud River's drying up on land subsidence in the Isfahan-Borkhar aquifer in Iran's central plateau. To facilitate this assessment, we utilize the Interferometric Synthetic Aperture Radar (InSAR) technique to estimate the vertical deformation velocity of the aquifer (average land subsidence rate). The results show that the Isfahan-Borkhar aquifer has experienced a significant annual decline of more than 25 m, with an alarming rate exceeding 0.8 m/year. Our analysis of 31 piezometric wells (P-Wells) from 2000 to 2022 reveals a downward monotonic (in 16 P-Wells) and nonmonotonic (in 12 P-Wells) trend in groundwater table changes. Moreover, the GW table in the P-Wells near the river depends entirely on river flow. Furthermore, our findings indicate that river regulation exerts a dominant role in the control of land subsidence. Consequently, when water flows in the Zayandeh-Rud River, the rate of land subsidence declines significantly, particularly in urban regions. Therefore, maintaining a constant flow of water in the river can prevent or reduce ongoing land subsidence in Isfahan.