| Title |
Probabilistic Evaluation of the Effect of Drought on Water Temperature in Major Stream Sections of the Nakdong River Basin |
| Authors |
서지유 ( Seo Jiyu ) ; 원정은 ( Won Jeongeun ) ; 이호선 ( Lee Hosun ) ; 김상단 ( Kim Sangdan ) |
| DOI |
https://doi.org/10.15681/KSWE.2021.37.5.369 |
| Keywords |
Copula; Environmental drought; Nakdong river watershed; Water temperature |
| Abstract |
In this work, we analyzed the effects of drought on the water temperature (WT) of Nakdong river basin major river sections using Standardized Precipitation Index (SPI) and WT data. The analysis was carried out on a seasonal basis. After calculating the optimal time scale of the SPI through the correlation between the SPI and WT data, we used the copula theory to model the joint probability distribution between the WT and SPI on the optimal time scale. During spring and fall, the possibility of environmental drought caused by high WT increased in most of the river sections. Notably, in summer, the possibility of environmental drought caused by high WT increased in all river sections. On the other hand, in winter, the possibility of environmental drought caused by low WT increased in most river sections. From the risk map, which quantified the sensitivity of WT to the risk of environmental drought, the river sections Nakbon C, Namgang E, and Nakbon K showed increased stress in the water ecosystem due to high WT when drought occurred in summer. When drought occurred in winter, an increased water ecosystem stress caused by falling WT was observed in the river sections Gilan A, Yongjeon A, Nakbon F, Hwanggang B, Nakbon I, Nakbon J, Nakbon K, Nakbon L, and Nakbon M. The methodology developed in this study will be used in the future to quantify the effects of drought on water quality as well as WT. |