珠江河口演变规律及治理利用问题

Evolutional Processes of the Pearl River Estuary and Its Protective Regulation and Exploitation

现代珠江三角洲形成具有发展的阶段性、形式的多样性和淤积的不平衡性等特点。因而近 5 0 0 0～ 6 0 0 0年来珠江河口演变有如下特征和规律 :(1)在纵向上 ,河口性质发生由废弃河口→河流优势型河口→河流—波浪型河口的转换变化 ;(2 )在横向上 ,向海凸伸的三角洲及其河流优势型河口和其两侧向陆凹入的河口湾或潮汐优势型河口相依并存 ,并随三角洲的发展 ,衍生出“河道”与“潮道”共生的现象 ,此是陆海动力耦合和相互作用的表现 ;(3)“河道”与“潮道”间的横比降愈来愈大 ,其间之横向汊道起着良好的调节作用。目前珠江河口的治理应强调保护利用问题 。

Formation by stages ,diversified landform patterns and spacious unevenness of deposition pattern are three principal features in the evolutional processes of modern Pear River delta.Consequently,the evolutional processes in the Pearl River estuary since 5,000～6,000a B.P. show following distinctive characteristics and rules:(1)The estuary type of the main stream(the West River)was changing from oceanic abandoned type to constructive river dominated type and to river wave mixed type of current Modaomen distributary mouth.(2)In lateral direction,it is interdependent and coexistent that the main body of Pear River delta protruding seaward with river dominated distributary mouth and the tide dominated estuaries incurving inland at both sides of the delta.As the delta was moving seaward,both of fluvial channel and tidal channel were formed,which gave a vivid expression to land and ocean interaction.(3)As the delta was moving seaward,the lateral gradient of water level between the fluvial channel in the main delta and the tidal channel in both sides of delta was increasing,and the lateral waterways connecting distributaries played an important role in adjusting the water level gradient.It was pointed out that the current estuary regulation should pay more attention to the characteristics of Pear River estuary and its evolutional processes.