Hydrology

Multi-temporal satellite data were used to examine changes in aufeis area and spatial configuration in the Chuluut River valley, Mongolia, and to compare seasonal vegetation dynamics among sites with different return frequencies of aufeis. Annual aufeis masks were derived from Landsat imagery for 1986–2025, while vegetation phenology was assessed using Harmonized Landsat–Sentinel-2 (HLS) data for 2016–2025. Mean aufeis area was 11.98 km² and declined significantly by approximately 0.084 km² per year, accompanied by spatial reorganization. The strongest climatic association was found with April–June precipitation in the preceding year. Hydrologically, aufeis acts as a temporary seasonal water store, retaining part of winter discharge and releasing meltwater during spring. Its decline and redistribution may alter the timing and pathways of seasonal water release, reduce delayed moisture inputs to floodplain surfaces, and modify water availability for riparian and meadow ecosystems. In meadows, the start of season (SOS) occurred later under frequent than infrequent aufeis recurrence. Peak and mean summer normalized difference vegetation index (NDVI) values remained high after aufeis melt-out. The highest integrated seasonal NDVI values occurred under intermittent aufeis recurrence.

Water quality indices are generally developed for specific water uses, but direct comparisons of indices designed for public water supply and irrigation using the same monitoring dataset remain limited. This study evaluated surface water quality in the Federal District (FD), Brazil, assessing its suitability for public drinking water supply and irrigation under different land uses. Eighteen sampling sites across rural, urban, and natural hydrographic units were monitored bimonthly from December 2017 to October 2019. A total of 12 sampling campaigns were conducted, resulting in 12 samples per site and 216 samples overall. The reported water quality indices were calculated using the median values obtained over the monitoring period. Twelve physical, chemical, and microbiological parameters were analyzed to calculate the WQI_CETESB (for raw water intended for public drinking-water supply after treatment) and the IWQI_FD (for irrigation). The WQI_CETESB classified 16 sampling sites as “Good” (52–79) and two as “Reasonable” (37–51), with no sites classified as “Excellent”. The IWQI_FD classified six sampling sites as “Excellent” (90–100), seven as “Good” (75–89), and five as “Average” (51–74). No significant differences were detected among broad land use categories, whereas seasonal differences were observed for water temperature, turbidity, total phosphorus, and total nitrogen. Multivariate analyses indicated site-specific patterns associated with anthropogenic and natural hydrogeochemical influences. Even in natural areas, water may not meet optimal conditions for irrigation. The IWQI_FD yielded more favorable classifications than the WQI_CETESB at several sampling sites, reflecting differences in parameter selection, weighting structure, classification thresholds, and intended uses. These findings reinforce the importance of use-specific water-quality assessment and demonstrate the value of WQIs as complementary tools for integrating complex datasets and supporting Integrated Water Resources Management (IWRM). For management purposes, index selection should be aligned with the intended water use, while critical individual parameters should also be evaluated alongside aggregated index scores.

Soil erosion and sediment redistribution in vineyards often exceed tolerable thresholds, but comparative field measurements across regions remain limited because studies use different methods and sampling designs. This study assesses soil redistribution in vineyards using a common field-based approach. Thirteen vineyard sites across Spain, covering contrasting climates, parent materials, soil types, management conditions, and vineyard ages (2–40 years), were surveyed using the Improved Stock Unearthing Method (ISUM). Soil surface changes were measured along systematic transects and combined with site-specific bulk density and vineyard age to estimate soil mobilization rates in t ha⁻¹ yr⁻¹. Measured surface changes ranged from −28 to +19 cm, while soil mobilization rates varied considerably among sites. The highest net soil losses were recorded in a young vineyard developed on limestone (−103.3 t ha⁻¹ yr⁻¹) and in a vineyard on marls (−87.7 t ha⁻¹ yr⁻¹). Other sites showed moderate net erosion (−3.9 to −15.4 t ha⁻¹ yr⁻¹), whereas positive balances (+7.2 to +17.9 t ha⁻¹ yr⁻¹) were observed in some older or more stable vineyards. Differences among sites suggest that vineyard age and parent material are relevant factors when interpreting erosion magnitude, while management conditions may contribute to the spatial variability of soil redistribution. Spatial maps based directly on ISUM measurements showed marked differences between erosion and deposition areas within individual vineyards, without the use of spatial interpolation. Applying the same ISUM protocol across contrasting vineyard conditions allowed soil redistribution patterns to be compared using a consistent field procedure. The results also showed the large variability that can occur among vineyard systems.