长江八卦洲汊道河床演变对航道的影响及对策

近60年来，长江南京八卦洲汊道经历了主支汊自然易位的演变过程，左汊（宝塔水道）淤积衰退，向弯曲方向发展，河水增加，石汊（草鞋峡捷水道）冲刷发展，向顺直方向演变，河水减少。宝塔水道的航道宽度，水深因大幅度淤积而减少，制约了左汊岸线的综合开发利用，影响了左汊左岸已建国有大型企业的经济发展，在保证右汊主汊地位前提下，适当增加左汊分流比，冲刷河槽，可形成基本满足岸线综合开发利用要求的航道，以促进国民经济的持续发展。

The effect of the riverbed evolution of fork channel in the Bagua Islet of the Yangtze River on the navigation channel and its countermea- sures

In recent 60 years, the fork channels in the Bagua Islet of the Yangtze River in Nanjing have experienced the natural evolution of main and branch fork channels, that is, the left fork channel (Baota Waterway) declined because of deposition and developed toward bend direction with the increase of channel length. But the right fork channel (Chaoxiexiajie Waterway) developed toward the straight direction with the decrease of channel length because of scouring. The great reduce of width and depth of navigation channel of Baota Waterway has restricted the comprehensive development and utilization along the banks of the left fork channel and affected the economic development of the existing large sized state owned enterprises in the left bank of the left fork channel. Under the prerequisite of guaranteeing the main fork position of the right fork channel, the ratio of water diversion should be increased to the left fork channel properly to scour the channel in order to form a navigation channel that can basically meet the needs of comprehensive development utilization along the banks to promote the sustainable development of national economy.