Assessment of contribution of major rivers inflow into the Dongting Lake, China

The development associated with rapid industrialization and urbanization in Dongting Lake region has been more complex due to large water demand. Therefore study of water variation within the lake region is necessary for wetland protection, conservation and its sustainable management. In this study monitoring of different Hydrological Control Stations, the calculation and analysis was carried out over 2014 based on hydrological data. The results indicated that seasons are the typical main driving factor for water variation in the Dongting Lake; among the rivers, Xiang, Zi, Yuan and Li (also known as “Sishui”) accounts for the major part of the inflow discharge into the lake, and therefore the overall trend is featured by a flow pattern from the southwest to the northeast (Chenglingji outlet).  The results also indicated that the inflow discharge of major rivers (Li, Yuan, Zi and Xiang) dominates other rivers with  approximately 58% input to the lake. On the other hands the discharge from Yangtze River is very low in dry season from December to February, and it becomes high up to the maximum level of 28500 m3/s during flood period from June to September which is approximately 42% of its annual inflow amount. Similarly, the annual input comparison between Yangtze River and major rivers showed that the large amount of inflow from Yangtze is observed from June to September, which accounted 76% of its total annual inflow to Dongting Lake. While the high inflow from major rivers is observed from May to August, which is estimated at 60% of the major rivers total annual inflow to Dongting Lake. This study has important practical significance for sustainable development of the water management in the Dongting Lake Basin.   Key words: Rivers, Dongting Lake, hydrological control stations, inflow discharge, Yangtze River.