| Recently, the drought situation is grim in Poyang Lake, along with the increasing droughts frequency in the Lake, various industries、 basic living、 as well as Lake’s ecosystem were affected, which has become a widely concerned problem. Based on the analysis of dry season(from October to March) hydrological regime changes in Poyang Lake, the recent low-water feature was described. In assessment of drought in Poyang Lake, the drought-limited water level in Poyang Lake was identified. Studies may contribute to scientifically understanding the dry and drought characteristics in Poyang Lake, and offering reference to drought relief and water resource utilization in Poyang Lake.This Paper selected the data of main control stations(runoff and water level stations)in Poyang Lake as the investigated subject, firstly analyzed the runoff and water level series’ changing trend and cycle features. The results show that the dry season average water level has a downward trend.The runoff of dry season has a main period of 21 a, and the averge water level in dry season has a main period of 28 a.This paper describes the characteristics of low-water status in recent years, the year 2003, 2006, 2007, 2009, 2011 were chosen as the typical dry year being analyzed; a study of the influence degree by main factors on dry season water level was done. The results show that the water level in Jiujiang station greatly affected the dry season water level.Runoff anomaly percentage index and the standardized runoff index were used to assess the drought in Poyang Lake. Compared with the meteorological drought assessment by other scholars, we can find that the two indexes are reliable for assessing drought. According to the formulating principle of drought-limited water level, define 8.0, 9.5, 12.0m as theⅠ, Ⅱ, Ⅲ level of drought-limited water level. The results of drought identification and assessment are consistent with other drought indexes, so the drought-limited water levels are reasonable. |
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