o:8138 Impact of Different Factors on Changes in Water Resources Availability en When considering trends in hydrological changes (HC) for one region, two questions arise: (1) Are they simply variations of one parameter (coincidence), or have they been initiated with certain causes; and (2) If they are not random, how do various significant environmental changes impact these trends, and how do they vary across the region. The most important environmental changes which could impact HC are changes in Temperature (T), Precipitation (P), Forest Cover (FC) and Human Use of water (HU). This paper sheds light on these questions for central Serbia (CS) based on a series (analyzed period 1949–2023) for 24 hydrological stations in CS, and 26 T stations and 38 P stations across the whole of Serbia. Estimation of FC changes and changes in HU are based on the available data for three larger regions, which cover the whole of central Serbia (western, central and eastern part). The results indicate that temperature is generally the most significant factor for the observed decrease in HC in central and especially eastern CS (impact slightly greater than 50%), while in the western part of CS, P and T the impacts on HC are about the same (both slightly lower than 50%). Other environmental changes (∆FC and ∆HU) generally exhibit a lower impact. The methodology offered for evaluating the impact of different factors on HC could also be applied to the other parts of the world where decreasing HC is observed. After presenting the methodology and results, the paper discusses the confidence of the results and cites some results from different Mediterranean and other countries/regions. Hydrological Changes, Forest Cover, Precipitation, Temperature, River Flow 1552101 1573-1650 1552099 10.1007/s11269-025-04310-7 2025-08-14T10:37:26.061Z 44 no 46 Dejan Dimkić Jaroslav Černi Water Institute, Belgrade, Serbia 0000-0003-4994-2683 Boris Pokorni Jaroslav Černi Water Institute, Belgrade, Serbia person 0000-0002-5468-6250 Zoran Simić Jaroslav Černi Water Institute, Belgrade, Serbia person 0009-0008-1387-1995 application/pdf 1662546 https://unilib.phaidrabg.rs/o:8138 no yes 1 70 92000001 71A04 Water Resources Management 39 9 Dordrecht, Netherlands Springer 2025 Received: 4 April 2025 Accepted: 2 July 2025 Published online: 04 August, 2025