近30年来太湖围湖利用及东太湖网围养殖动态变化研究

DYNAMIC MONITORING OF LAKE RECLAMATION IN THE TAIHU LAKE AND LAKE ENCLOSURE CULTURE OF THE EAST TAIHU LAKE IN RECENT 30 YEARS

利用多期遥感影像从时间、空间和利用类型3个方面分析了近30a来太湖围湖利用及东太湖网围养殖的时空变化特征。结果表明:1979～2008年,太湖围湖利用面积总计达16.004 2km2;其中1979～2001年,太湖围湖利用面积9.509 0km2,年均围湖利用面积0.432 2km2,围湖利用的主要用途为水产养殖,鱼塘用地占该段期间围湖利用面积的56.53%;2001～2008年,围湖利用面积6.495 2km2,年均围湖利用面积0.927 9km2,围堰取土用地占该段期间围湖利用面积的52.28%。1979年以来,东太湖网围养殖规模逐渐增大,1979年东太湖网围养殖面积8.343 4km2,2001年网围养殖面积达100.272 6km2,占东太湖水面面积的74.65%,网围养殖区域的分布逐渐从湖岸边沿处向湖心处扩展,至2006年,除主航道外,东太湖整个湖面几乎遍布网围,并呈现向西太湖扩展的趋势,随着东太湖水环境问题日益突出及太湖整治力度的加大,东太湖网围养殖面积从2006年的105.873 2km2下降为2008年92.969 1km2,网围养殖区域的逐渐缩小及自由水域面积的逐渐增大,将真正实现太湖流域经济-资源-环境的可持续发展。

Spatial-temporal dynamic changes in ponding and enclosure culture of the Taihu Lake especially the changes of lake area and lake enclosure culture in the east Taihu Lake were studied with the aid of Landsat TM,Landsat ETM+ and Alos image.The result showed that the area of land reclamation was 16.004 2 km2 in Lake Taihu from 1979 to 2008.The area of land reclamation was 9.509 km2 from 1979-2001 and the area of land reclamation was 0.432 2 km2 per-year.The land reclamation was used for water aquaculture,and the area of ponding was 56.53% in total area of land reclamation from 1979 to 2001.The area of land reclamation was 6.495 2 km2 from 2001 to 2008,and the area land reclamation was 0.927 9 km2 per-year.The land reclamation was used for earth-filling cofferdam,and the area of earth-filling cofferdam was 52.28% in total area of land reclamation.The scope of enclosure culture had become large since 1979 and the enclosure culture had bestrewed the whole of the East Taihu Lake today.The area of enclosure culture in 1979 was 8.3434 km2 and had increased 100.272 6 km2 since 2001,which occupied 74.65% in total area of the East Taihu.Higher density of enclosure culture had become a big problem of water resource exploitation in the East Taihu Lake.Based on the analysis of the situation and problems of the ecological environment,some countermeasures were suggested for the exploitation of the lake.