Experience in water resources management under the climate change conditions on the example of Norway

Abstract

Climate change in Norway is occurring gradually, yet its consequences are becoming increasingly evident. There is a steady rise in average temperatures, an increase in annual precipitation and runoff, as well as a growing intensity of extreme weather events. Various regions of the country are experiencing more frequent and intense rainfall, which directly affects the hydrological regime and the formation of surface runoff. These climatic shifts raise concerns due to their impact on freshwater sources, especially during periods of heavy precipitation, when higher levels of bacterial contamination, increased water turbidity, and intensified coloration are observed; this indicates elevation of concentrations of organic matter and suspended particles in the water. Amid growing climate risks, there is a pressing need for thorough regional analyses of how these changes affect water quality. Such analyses form the foundation for timely upgrades to water treatment facilities, as the increasing burden on filtration and disinfection systems could compromise their effectiveness, particularly in smaller settlements. By the end of the 21st century, the situation is expected to worsen, with forecasts indicating a further rise in waterborne pollutants due to soil erosion, runoff from agricultural lands, and urbanized areas. According to climate research, the rise in air temperature, especially when combined with changes in precipitation patterns, will significantly influence hydrological processes [1]. Precipitation in Norway is expected to become predominantly convective in nature, occurring more frequently and with greater intensity [4]. This will pose new challenges for water supply systems, particularly in maintaining consistent drinking water quality. Norway has already experienced an increase in the average annual temperature of about one degree Celsius since the early 20th century [1]. This trend is accompanied by shifting snowmelt seasons, increased winter and spring runoff, and changes in the amount and distribution of precipitation. A particularly noticeable rise in precipitation occurred after the 1970s, amounting to approximately an 18% increase compared to initial values.