ABSTRACT
Objective To understand the distribution of Oncomelania hupensis snails in source areas of the east route of Southto-North Warter Diversion Project and evaluate the effects of the snails on the safety of water transfer.Methods The investigation of snail distribution was carried out in the source areas of the east route of South-to-North Warter Diversion Project every spring.The method of the random sample combined with environmental sample was used for the field investigation.The beach land in the stilling pool of Jiangdu Pumping Station was selected as a surveillance site to observe the snail spread.Results The areas of the snail habitats and infected snails were 256.11,184.55,164.92,121.16 hm~2 and 8.27,1.0,1.0,0 hm~2 respectively in the source areas of the east route of South-to-North Wafter Diversion Project from 2006 to 2009.The densities of living snails had a downtrend,too.Google Earth showed that the areas of snail habitats distributed mainly in the Jiajiang River and Mangdao River in the source areas.The snail habitats were detected in the beach land in the stilling pool of Jiangdu Pumping Station.The research results showed that the snail spread related to the wastes from the river of drawing water.Conclusion There are the risks of snail spread in the source areas of the east route of South-to-North Wafter Diversion Project,so that the long-term surveillance and control on the snails is very necessary.