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During the flood season of 2016, the middle and lower reaches of the Yangtze River suffered the worst flooding since 1999, involving Hunan, Hubei, Anhui, Jiangxi and Jiangsu provinces and the Taihu Basin. Based on the field survey at eight counties on both sides along the Yangtze River in Anhui Province, this paper analyses the features of rainstorm, flood and the resulting disaster in 2016 over there, and identifies problems and difficulties existing in flood prevention and disaster reduction under the new situation of social and economic development. Furthermore, this paper discusses the coping strategies and measures on advancing the comprehensive flood management mode of human-water harmony, managing middle and small rivers and strengthening the key basic research on flood control and disaster reduction under the new situation. [ABSTRACT FROM AUTHOR]

Heavy rainfall hit the Yangtze-Huai Rivers basin (YHRB) of east China several times during the pro-longed 2007 mei-yu season, causing the worst flood since 1954. There has been an urgent need for attaining and processing high-quality, kilometer-scale, hourly rainfall data in order to understand the mei-yu pre-cipitation processes, especially at the mesoß and smaller scales. In this paper, the authors describe the construction of the 0.07°-resolution gridded hourly rainfall analysis over the YHRB region during the 2007 mei-yu season that is based on surface reports at 555 national and 6572 regional automated weather sta-tions with an average resolution of about 7 km. The gridded hourly analysis is obtained using a modified Cressman-type objective analysis after applying strict quality control, including not only the commonly used internal temporal and spatial consistency and extreme value checks, but also verifications against mosaic radar reflectivity data. This analysis reveals many convectively generated finescale precipitation structures that could not be seen from the national station reports. A comprehensive quantitative as-sessment ensures the quality of the gridded hourly precipitation data. A comparison of this dataset with the U.S. Climate Prediction Center morphing technique (CMORPH) dataset on the same resolution suggests the dependence of the latter's performance on different rainfall intensity categories, with sub-stantial underestimation of the magnitude and width of the mei-yu rainband as well as the nocturnal and morning peak rainfall amounts, due mainly to its underestimating the occurrences of heavy rainfall (i.e., >10mmh-1). [ABSTRACT FROM AUTHOR]

Poyang Lake in Jiangxi Province is the largest freshwater lake in China and is historically a region of significant floods. Maximum annual lake stage and the number of severe flood events have increased during the past few decades because of levee construction that reduced the area available for floodwater storage. The most severe floods since 1950 occurred during 1954, 1973, 1983, 1995, and 1998. Each of these floods followed El Niño events that influence the Asian monsoon and that are directly linked to rainfall in the Changjiang (Yangtze River) basin. The 1954 flood was the largest ever recorded until the 1990s. That year the peak Changjiang stage at Hukou was 21.6 m, which was 1.6 m above the previous record high. The last major flood on the Changjiang was during 1998, when the peak Changjiang stage reached 22.5 m, higher than during 1954, even though peak discharge was lower. The most severe floods, including those in 1954 and 1998, require both 1) high rainfall and tributary discharge into Poyang Lake and 2) high Changjiang discharge and stage at Hukou that backflows into the lake or slows Poyang Lake drainage. Since gauging stations were established on the Changjiang, these conditions always occurred following an El Niño. [ABSTRACT FROM AUTHOR]

Four major reaches of Chiangjang (Yangtze River) were analyzed for the period 1956-2007 in terms of long-term trends in suspended sediment gain and loss in each reach, the relation of input and output to within-reach sediment fluxes, and the impacts of dam construction on reach sediment dynamics. The temporal and spatial patterns of within-reach sediment dynamics correspond closely with river morphology and also reflect basin conditions over the past few decades; thus they are conditioned by coeval trends in climate, hydrology, and land use. The study period encompasses both unusually wet years (e.g., 1998) and unusually dry periods (e.g., 2006). There are suggestive coincidences between changes in the suspended sediment regime and innovations in land use, sediment mining, and dams. The relatively strong statistical relation between sediment input and output for each of the four study reaches, and weak relations between storage and output, imply that most sediment supplied to each reach is delivered from upstream and that relatively small amounts of sediment are recruited within each reach. Cumulative departure plots reveal epicycles of sediment exchange varying from 15 to 40 years, implying a characteristic fine sediment storage time on the order of decades. Shorter epicycles (5-8 years) are commonly related to sediment influx associated with major floods. [ABSTRACT FROM AUTHOR]