How to cite: Mihalea, D.-M., Perju, R., Lupu, I., Ungureanu, M., Lăzuran (Axinte), A.L. (2020) The Characteristics of the Maximum Flow in the Upper Basin of Crişul Negru River . 2020 ”Air and Water – Components of the Environment” Conference Proceedings, Cluj-Napoca, Romania, p. 157-168, DOI: 10.24193/AWC2020_15.
THE CHARACTERISTICS OF THE MAXIMUM FLOW IN THE
UPPER BASIN OF CRIŞUL NEGRU RIVER
Dan-Mircea MIHALEA, Ruth PERJU, Iulia LUPU,
Mihaela UNGUREANU, Anamaria Liana LĂZURAN (AXINTE)
ABSTRACT. – The paper aims to highlight the characteristics of the maximum flow in the Upper Basin of Crișul Negru River. The catchment area has 947 km2 and it is located in the Western Carpathians, upstream Beiuș city. In order to achieve the proposed purpose, the hydrological and meteorological data recorded between 1973-2018 at five gauging stations located in the study area (on the main watercourse and on some important tributaries) were statistically analyzed, namely mean monthly temperatures and amounts of precipitation, mean daily discharges, maximum monthly and annual discharges and hydrographs of the largest floods. The interannual variability of the maximum annual discharges shows downward trends, but statistically significant at only two of the analyzed measurement points (Ștei g.st. on Crișul Băița River, with 5% significance level and Pietroasa g.st. on Crișul Pietros River, with 10% significance level). Seasonally, the maximum annual discharges are most frequently recorded during winter and spring (between 60% and 70% of cases in the analyzed period). The mean daily discharges were analyzed to identify the floods/periods of high flow and their seasonal and annual frequency at the five gauging stations (a flood/period of high flow being considered any value that exceeds three times the mean multiannual discharge): the most frequent are the spring floods (32%-41%), induced by heavy rainfall or associated rainfall snowmelt events and the winter floods (18%-23%), mostly caused by sudden snowmelt, sometimes associated with rainfall events. The summer rainfall induced floods represent 21% to 26% of the total and the lowest frequency is recorded in autumn at all five gauging stations. For the floods with the largest peak discharge (exceeding the average of the maximum annual discharges), the characteristic elements were determined, of which the average values of the form coefficients are between 0.22 and 0.27 and the average total durations between 1 and 12 days.
Keywords: Maximum flow, variability, frequency, flood, Upper Basin of Crișul Negru River
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