Lake Sevan, 1242 km² large, is the largest lake in the Caucasus and also Armenia. This mountain lake serves as a natural water reservoir for the Hrazdan River, which is critical for the water supply to the capital Yerevan, and the Ararat Valley, the most important agricultural region of Armenia. The annual outflow from the lake shall not exceed 170 million m³. Agriculture is an important economic sector within the lake’s basin, whereby summer and perennial crops depend on irrigation. This study used remote sensing to map the evapotranspiration of agriculture and other vegetation types to assess, in how far agriculture poses a pressure on the water balance of the lake. From 2023 to 2025, the evapotranspiration averaged across all cropland ranged between 204 mm and 307 mm, which coincides with the low yields of agriculture. During the growing season, evapo-transpiration of summer and permanent crops exceeded precipitation by 4.2 to 4.5 mil-lion m³, which is small compared to the annual outflow of 170 million m³. The annual precipitation exceeded evapotranspiration of cropland, including irrigated cropland. The findings suggest that, under current land use and climatic conditions, agriculture around Lake Sevan does not pose significant pressure on the lake’s water balance and ability to sustain its inflow into Hrazdan River.

Lake Sevan, 1242 km² large, is the largest lake in the Caucasus and the largest lake in Armenia. This mountain lake serves as a natural water reservoir for the Hrazdan River, which is critical for the water supply to the capital, Yerevan, and the Ararat Valley, the most important agricultural region of Armenia. The annual outflow from the lake shall not exceed 170 million m³. Agriculture is an important economic sector within the lake’s basin, with summer and perennial crops partly depending on irrigation. This study used remote sensing to map the evapotranspiration of agriculture and other vegetation types to assess the extent to which agriculture poses pressure on the lake’s water balance. From 2023 to 2025, the evapotranspiration averaged across all the cropland in the study area ranged between 204 mm and 307 mm, which coincides with low yields of agriculture. During the growing season, evapotranspiration of summer and permanent crops exceeded precipitation by 4.2 to 4.5 million m³, which is small compared with the annual outflow of 170 million m³. Overall, the annual precipitation exceeded evapotranspiration of cropland, including irrigated cropland. The findings suggest that, under current land use and climatic conditions, agriculture around Lake Sevan exerted limited pressure on the lake’s water balance for the years 2023–2025 and is unlikely to substantially affect its capacity to sustain the required outflow into the Hrazdan River.

Kazakhstan’s Ili River delta nourishes a unique wetland ecosystem in arid Central Asia. The delta is dominated by common reed [Phragmites australis (Cav.) Trin. ex Steud.], an ecologically and economically significant species that is sensitive to water levels. We used machine learning methods, including the Random Forest algorithm, to classify common reed-containing wetland vegetation and water surfaces in the delta based on satellite data from 2000 to 2023. The remote sensing results were integrated with field-based geobotanical studies conducted between 2017 and 2019. These studies, which facilitated identification of three classes of vegetation: meadow, marsh and aquatic, also revealed a good correspondence between predicted and measured common reed biomass per unit area. The long-term dynamics of four wetland communities with a common reed content of ≥25% were analyzed with respect to significant interannual variability in the flow of the Ili River. The highest water inflows and water surface areas in the delta were recorded in 2002, 2010 and 2016, and in each case, a statistically significant expansion of common reed was observed one year later. Common reed areas subsequently declined—rapidly or after a lag of several years. Temporal expansion and contraction of these areas following pulses of water differed substantially from that of overall wetland vegetation as measured previously. The identified patterns have important scientific and practical significance for assessing the stability of the surrounding wetlands, preservation of the delta environment, and sustainable use of common reed.