Multivariate Assessment of Low-Flow Hazards via Copulas: The Case Study of the Çoruh Basin (Turkey)

Bivariate modeling and hazard assessment of low flows are performed exploiting copulas. 7-day low flows observed, respectively, in the upper, middle and lower parts of the Çoruh basin (Turkey) are examined, considering three pairs of certified stations located in different sub-basins. A thorough sta...

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Bibliographic Details
Published inWater (Basel) Vol. 12; no. 10; p. 2848
Main Authors Tosunoğlu, Fatih, Salvadori, Gianfausto, Yilmaz, Muhammet
Format Journal Article
LanguageEnglish
Published Basel MDPI AG 01.10.2020
Subjects
Basins
Bivariate analysis
Case studies
Drought
Electricity distribution
Frequency analysis
Hydrology
Low flow
Multivariate analysis
Rain
Random variables
Rivers
Standard deviation
Statistical analysis
Statistics
Stream flow
Water shortages
Weather hazards
China
Anatolia
Turkey
Georgia
United States > US
Black Sea
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Summary:Bivariate modeling and hazard assessment of low flows are performed exploiting copulas. 7-day low flows observed, respectively, in the upper, middle and lower parts of the Çoruh basin (Turkey) are examined, considering three pairs of certified stations located in different sub-basins. A thorough statistical analysis indicates that the GEV distribution can be used to model the marginal behavior of the low-flow. The joint distributions at each part are modeled via a dozen of copula families. As a result, the Husler–Reiss copula adequately fits the joint low flows in the upper part, while the t-Student copula turns out to best fit the other parts. In order to assess the low-flow hazard, these copulas are then used to compute joint return periods and failure probabilities under a critical bivariate “AND” hazard scenario. The results indicate that the middle and lower parts of the Çoruh basin are likely to experience the largest drought hazards. As a novelty, the statistical tools used allow to objectively quantify drought threatening in a thorough multivariate perspective, which involves distributional analysis, frequency analysis (return periods) and hazard analysis (failure probabilities).
ISSN:2073-4441
2073-4441
DOI:10.3390/w12102848