Analysing Seasonal Hydroclimatic Variability to Support Managed Aquifer Recharge Planning in Kazakhstan

Abstract Kazakhstan has been experiencing water scarcity due to high inter- and intra-annual precipitation and streamflow variability, which adversely impacts the country’s agricultural production and economy. In order to design suitable adaptation measures, a detailed analysis of characteristics and trends in climate data is essential. This study analyses recent climate data (1981–2019) and global gridded datasets on water balance components for two Kazakh regions. The data was analysed using Mann–Kendall trend test, extreme precipitation indexes, analysis of wet/dry spells and droughts. The results indicate that while the average annual precipitation amounts were not significantly different between the regions, there was a distinct intra-annual variability. Significant trends in hydroclimatic variables appear in the south during winter and spring, and in the north mainly in spring. No significant trends are observed for extreme precipitation. Evapotranspiration controls the water balance in both regions. Potential water available for groundwater recharge is higher in the north. Snowpack in the south is highly variable and shows a significant decreasing trend. Based on the results, managed aquifer recharge (MAR) is proposed as a potential solution to enhance water availability throughout the year, leveraging the highly variable precipitation and streamflow patterns. In both cases, the irregularly available water resources, such as spring snowmelt and heavy summer rains, can be stored through MAR schemes, thereby providing reliable support to water supply systems. This approach can serve as a countermeasure to the recurrent dry spells and droughts in the region, as well as to the climate-induced alterations of the local water balance. Graphical Abstract Graphical abstract description: This study examines hydroclimatic conditions and identifies changes and challenges in two distinct regions of Kazakhstan: the north and the south. Kazakhstan is facing water scarcity exacerbated by high climate variability. Rising temperatures, distinct and highly variable precipitation patterns in the northern and southern regions, and recurrent droughts threaten both agriculture and overall water security. The study analysed meteorological, remote sensing and reanalysis data for 1981-2019 using trend tests of key climate variables, extreme precipitation indices, extreme weather events like droughts, wet and dry spells, and the calculation of potential water available for groundwater recharge (GWR). The regions experience distinct wet and dry periods with evapotranspiration being the main component of water balance. Droughts are recurrent at both regions, though there is a clear difference in drought occurrence and intensity between them. Water balance analysis of the cold season indicated that there is a significant GWR (28% of annual precipitation for north and 24% for south). The mean GWR is higher in the north, the southern region is characterized by high spatial variability. Analysing hydroclimatic variability Managed Aquifer Recharge (MAR) is proposed as a key strategy for mitigating water scarcity, floods, and droughts. In the north significant spring snowmelt (currently source of flooding) and heavy summer rainfall could be used for MAR. Whereas in the south the focus should be to store snowmelt and spring precipitation to combat the region’s severe summer droughts and reduce reliance on transboundary water sources.