Impacts of heavy rain and floodwater on floating debris entering an artificial lake (Daecheong Reservoir, Korea) during the summer

초록

Floating debris entering a reservoir is one of the major environmental issues to be dealt with in terms of water resource management in many countries of the world, as it may negatively impact ecosystems and cause economic damage. Our study examined the amount of floating debris and actual conditions experienced during the summer each year in an artificial lake located in the temperate region for 26 y. In particular, the rainfall and inflow characteristics were compared with the main influential factors for transporting floating debris to the reservoir. The maximum daily rainfall and inflow were important variables in the meteorological and hydrological characteristics of the reservoir operation during the summer. When these factors were influenced, most of the floating debris that was widely scattered in the watershed was supplied by the rapid flow of streams and rivers. The range and mean value of the floating debris weight accumulated within the reservoir were 421.0-34,137.0 m(3) y(-1) - and 8,758.4 m(3) y(-1), respectively, and the difference between the years was very large. The maximum daily inflow was positively correlated with maximum daily rainfall (r = 0.843, p < 0.05). Based on linear regression, the regression between the floating debris and the maximum daily inflow (r(2) = 0.9092, p < 0.001) showed a better fit than that between the floating debris and the maximum daily rainfall (r(2) = 0.8250, p < 0.001). They showed an almost linear relationship, and the floating debris distribution above and below 20,000 m(3) y(-1) was contrasted. In addition, the frequency distribution of the event was relatively dense below 120 mm d(-1) of rainfall and below 3,000 m(3) d(-1) of inflow, and the event was rare as the maximum daily rainfall and inflow increased. Finally, the average load of floating debris per unit area of the watershed was approximately 2.1 m(3) km(-2), and further details on the loading should be understood in terms of effective pollutant management.

키워드