Regulating Effect of Dongting Lake and Impacts on Runoff in the Jingjiang Reaches of the Yangtze River

洞庭湖对荆江径流有高效率的调节作用,根据长系列水文资料分析表明,荆江径流经调节后,年平均径流量、汛期径流量与汛枯期径流比分别减少了 26.3%、32.9%与 32.4%.年平均径流量与汛期径流量均呈沿程递减.这些在长江干流都是独一无二的.下荆江的流量最大变化幅度系数 Qk 为 0.892,在长江干流属最小.;The Dongting Lake has a high efficiency in regulating runoff of the Jingjiang Reaches of the Yangtze River.Based on the analysis of long-term hydrological data, after the regulation of runoff, the annual average runoff amount, runoff amount of flood season and ratio of runoff amount of flood season to dry season decreased by 26.3%, 32.9% and 32.4%, respectively.Annual average runoff amount and runoff amount of flood season decreased along the liver-All these are quite unique in the main stream of the Yangtze River-The maximum discharge amplitude Qk is 0.892 in the lower Reaches of the Jingjiang River which is the smallest among the main stream of the Yangtze River.