Serhan Yeşilköy , Özlem Baydaroğlu , Ibrahim Demir

The exacerbation of floods and the extension of droughts, attributed to climate change and other human-induced factors, are posing a substantial risk to communities by causing water scarcity and insecurity. The significance of safeguarding water resources and managing them is increasingly gaining prominence. Snow is an efficient source of water for recharging groundwater compared to rainfall. This is attributed to its gradual melting process and capacity to infiltrate the soil, thereby providing sustenance to the groundwater. Thus, snow drought can be considered a major contributing factor to the issue of water scarcity. The objective of this study was to investigate the evolution of snow drought over the period spanning from 1980 to 2022, as well as its impact on agricultural drought across the Upper Mississippi River Basin (UMRB). This research employed the AgERA5 reanalysis gridded data at surface level with a spatial resolution of 0.1°, obtained from the European Center for Medium-Range Weather Forecasts (ECMWF), to assess the snow drought. An analysis is conducted for comparison between the spatial estimations of snow drought in the UMBR and two other drought indicators, namely the evaporative demand drought index (EDDI) and water deficit amounts. The effects of the El Niño and La Niña phenomena on the UMRB as well as the results of the summer drought conditions were reviewed. The results point to two important findings. The former is that the snow-drought-affected zones show an increasing trend from the past to the present in the UMRB. The latter is that severe snow droughts in the winter of a water year trigger severe agricultural droughts in the summer months of the same water year. It is seen that monitoring snow droughts is as essential as following rainfall regimes in the planning of water resources, agricultural production, and irrigation methods.