Abstract: Objective Objective To study the drifting law of floats and potential risks of Oncomelania hupensis diffusion in the water diversion rivers of the east route of South?to?North Water Diversion Project. Methods Methods The O. hupensis snails in the river chan? nels were monitored by the salvage method and snail luring method with rice straw curtains，and the diffusion possibility of snails along with water was assessed through the drift test of floats with GPS. Results Results In the flood seasons from 2006 to 2013， totally 8 338.0 kg of floats were salvaged，and 2 100 rice straw curtains were put into water in the Li Canal and Jinbao shipping channel，but no Oncomelania snails were found. The drift test of floats with GPS before water diversion showed that the flow ve? locity on water surface（northbound）was 0.45 m/s，the average drift velocity of the floats was 0.56 - 0.60 m/s，and the average drift distances each time were 999.70 - 1 995.50 m in the Gaoshui River section，while there were no obvious drift in Jinbao shipping channel section. During the water diversion period，the flow velocity on water surface（northbound）was 0.45 m/s，the average drift velocity of the floats was 0.35 - 0.41m/s，and the average drift distances each time were 1 248.06 -1 289.44 m in the Gaoshui River，while in Jinbao shipping channel section，the flow velocity on water surface was 0.28 m/s，the average drift velocity of the floats was 0.25 - 0.27 m/s，and the average drift distances each time were 477.76 - 496.38 m. The drift test showed that the floats gradually closed to the river bank as affected by water flow，wind direction and ship waves，when blocked by the reeds，water plants or other obstacles，and they would stopped and could not continue to drift without outside help. Con Con? ? clusions clusions There are no Oncomelania snails found in the river channels of the east route of South?to?North Water Diversion Proj? ect. The drifting distance of the floating debris along with the water is restricted by the flow rate and shore environment.

Key words: Oncomelania hupensis snail；Schistosomiasis；Drift；Diffusion；GPS；East route of South?to?North Water Di? version Project

摘要： 目的 目的 研究南水北调东线工程输水河道漂浮物漂流规律和水体钉螺扩散的潜在风险。方法 方法 采用打捞法和稻 草帘诱螺法对南水北调东线工程输水河道水体钉螺进行监测， 并通过GPS定位漂流试验对输水河道中钉螺随水扩散的 可能性进行评估。结果 结果 2006-2013年汛期， 在南水北调东线工程里运河及金宝航道打捞漂浮物8 338.0 kg， 投放稻草帘 2 100块， 均未发现钉螺。漂浮物定位漂流试验表明， 东线工程通水前高水河段表层北向水面流速为0.45 m/s时， 搭载 GPS定位器的漂浮物 （GPS漂浮物） 平均漂流速度为0.56 ~ 0.60 m/s， 平均每次漂流999.70 ~ 1 995.50 m； 金宝航道段则无 明显漂流。试通水期高水河水面流速为0.45 m/s时， GPS漂浮物平均漂流速度为0.35 ~ 0.41 m/s， 平均每次漂流1 248.06 ~ 1 289.44 m； 金宝航道段水面流速为0.28 m/s时， 平均漂流速度为0.25 ~ 0.27 m/s， 平均每次漂流477.76 ~ 496.38 m。漂流 试验显示GPS漂浮物在水流、 风向、 船行波作用下， 逐渐向岸边靠拢， 在受到芦苇、 水草或其他障碍阻滞时则停止不前， 如 无外力帮助则不能继续漂流。 结论 结论 南水北调东线工程输水河道水体监测未发现钉螺， GPS定位漂流试验显示漂浮物 随水漂流距离受流速和岸边环境限制。

关键词: 钉螺；血吸虫病； 漂流；扩散； 全球定位系统； 南水北调东线工程