Determination and assessment of the groundwater table and mineralization in irrigated areas (Xojeli district, Republic of Karakalpakstan)

Abstract

Irrigated areas in the Aral Sea Basin are becoming highly saline due to the ascendant groundwater table and groundwater mineralization. This, in turn, leads to a decrease in soil fertility in agriculture and negatively affects the food security of basin countries. In the research work, seasonal changes in the groundwater table and mineralization during the periods of 2015 and 2023 were evaluated on the irrigated lands of the Xojeli district in the Republic of Karakalpakstan (Uzbekistan). Field monitoring was carried out on 142 observation wells using traditional methods of measuring the groundwater table and mineralization. Then, the obtained data was statistically analyzed, and maps based on the geoinformation system (GIS) were created by the inverse distance weighting (IDW) interpolation method for the study period. Furthermore, a correlation coefficient analysis was applied to find a relationship between climatic patterns, and groundwater table, and mineralization. Results based on statistical analysis present steady fluctuations in the groundwater table and wild fluctuations in mineralization over a period of nine years. The average water table below surface and mineralization in April was determined by 1.55 m and 2.94 g/l, in July by 1.78 m and 2.96 g/l, and in October by 2.18 m and 2.56 g/l. The visual maps created in accordance with the GIS-based method show that average values for the groundwater table in the irrigated areas were 1.5–2 m and 2–3 m (57.9% and 27.8%), and mineralization was 1-3 g/l and 3-5 g/l (62.4% and 36.5%). A correlation coefficient (r) shows a low relationship between the chosen variables.