RiTiCE: River Flow Timing Characteristics and Extremes in the Arctic Region

Abstract

(1) Background: river ice has a significant impact on nearly 66% of rivers in the Northern Hemisphere. Ice builds up during winter when the flow gradually reduces to its lowest level before the spring melt is initiated. Ice-induced floods can happen quickly, posing a risk to infrastructure, hydropower generation, and public safety, in addition to ecological repercussions from the scouring and erosion of the riverbeds. (2) Methods: we used the annual daily hydrograph to develop a RiTiCE tool that detects the break-up date and develops indices to analyze timing characteristics of extreme flow in the Tana and Tornio Rivers. (3) Results: the study showed that low-flow periods in two rivers had a significant trend with a confidence level of 95%. Additionally, it was observed that the occurrence date of seasonal 90-day low- and high-flow periods occurred earlier in recent years. Conversely, the Tana River showed a negative trend in its annual minimum flow over the century, which is the opposite of what happened with the Tornio River. (4) Conclusions: the method can be used to detect the date when the river ice breaks up in a given year, leading to a better understanding of the river ice phenomenon.

Large-Scale Hydrological Models and Transboundary River Basins

“…Thus, the grid cell representing the river's course at national boundaries corresponds to the waters entering the downstream country. The runoff data sources used for the validation of the applicability of the large-scale hydrology models in the case study transboundary basins are derived from (i) the 1st revision of the RBMPs of the River Basin Districts of Epirus (EL05), Central Macedonia (EL10), Eastern Macedonia (EL11), and Thrace (EL12) (e.g., [45,46]), which contain the official hydrological data of Greece; (ii) the 2nd Second Assessment of Transboundary Rivers, Lakes and Groundwaters [29], which contains interannual averaged river discharge figures in both parts of a transboundary basin; and (iii) the Global Runoff Data Centre (GRDC) [47], which is an international hydrological data and information repository under the auspices of the World Meteorological Organization, with its data being used by numerous scholars [48,49]. All the aforementioned data are publicly available on the internet, with their sources given in the "Data availability statement" section.…”