江滩型血吸虫病流行区江滩冲淤变化的定量研究

本研究采用测量陆地地形图的方法，对镇江市丹徒县世业洲16km江段进行了江滩冲淤变化景算。结果：1973年－1987年14年间，该江段累计冲刷江滩面积193．60万m2，淤涨江滩面积115．40万m2，净减少江滩面积67．90万m2。江岸滩以冲刷为主，冲淤比为1:0.36；江心洲滩以淤积为主，冲淤比为1：1．27，且呈洲头冲刷，洲尾淤积态势。世业江心洲滩年均新增洲滩面积1．19万m2，占该洲1981年以来年均增加江滩钉螺面积的14．46％。揭示了两种类型江滩的冲淤数量关系，为长江中下游地区洲滩不断扩大，并不断有新洲滩形成提供了理论依据。

QUANTITATIVE STUDY ON FLUCTUATION OF MARSHLAND SIZE IN SCHISTOSOMIASIS ENDEMIC AREA

The fluctuation of marshlands in Siyia,Zhengjiang City ranging for 16 km in lenth along the river bank was observed and calculated by measuring on the map. The result showed that due to river tide,a total of 1 936 000 m2 marshlands were scoured away,while 1 257 000 m2 marshlands were enlarged,as a result, 679 000 m2 marshlands were lost. The marshlands along the river bank were mainly scoured away,the ratio between the enlarged and the scoured away marsh1ands was 1: 0. 36, in contrast,the marshlands in isolated islet were mainly enlarged (with a ratio of 1: 1. 27). The average size of marshlands enlarged annually was 11 900 m2,and 14. 46% of which were infested with snails. It is indicated that the enlargement of snail infested areas is not due to new enlarged marshlands but mainly due to snail migration and change of control strategy.