近年来太湖流域中小型湖群的网围水产养殖业带来了十分可观的经济效益，挑、涌湖经遥感分析网围养殖面积占总湖水面积75％以上，属超密度网围。超密度网围养殖的负面效应是湖水营养盐急剧增高，水草资源大幅度减少，从而破坏了湖泊的生态平衡，恶化了湖水环境。采用15年以来的陆地卫星影像结合航空数据，对研究区的水资源利用类型、空间分布及变化状况进行了分析解译和目标分类，结合佃技术，对各类型进行了面积量算，推算了网围养殖密度，同时遥感分析了养殖水域环境和水草资源的变化，并展开了野外实地调查验证。

With Land satellite data of fifteen years combining aero data, this paper analyzed and studied 15 years' dynamic change of water resources using types and water quality by remote sensing technique and field investigation in Taohu and Gehu Lake of Taihu drainage area. The used water resources types were divided into purse net area for breeding fish, fish pool surrounded, bottomland used, inning farm and natural lake by remote sensing approach. The actual area of different using types and density of purse net in some period were calculated with GIS approach. For the purse net of breeding fish in lake bringing a lot of economical benefits in recent years, purse net area and natural lake area have been changed rapidly for about 15 years. There was no purse net area in 1980s. In 1994, the ratio of purse net area to total lake area is 15% in Gehu Lake, and 27% in Taohu Lake. However, the ratio rapidly increased up to 78.8% in Gehu Lake, and up to 83.8% in Taohu Lake in 1998. This ratio greatly exceeds that of logical purse net area to total lake area, which should be less than 20%. Multi-spectral remote sensor can inspect and survey the dynamic change of purse net density at any time, so that the results may avoid false area data that are caused for the personal sake. Excessive density of purse net for breeding may cause aquatic plants decreasing greatly. This paper analyzed 15 year's occupied proportion change of the aquatic plants by remote sensing approach in Taohu and Gehu lakes. 1980s, the proportion of aquatic plants occupid area to total lake area is more than 50% in Gehu Lake, and is more than 75% in Taohu Lake. In the mid-1990s, a lot of aquatic plants were cut down. There are a few aquatic plants in Gehu natural lake area protected. In 1998, only about 5% proportion of aquatic plants occupid area existed in the middle of Taohu Lake. Most space of the lakes could be used as purse net for breeding fish. This case brought on that the utilized value of the lakes by way of drinking, tour and aquatic animals and plants resources declined greatly. Furthermore, the content of nitrogen and phosphorus in the lakes was increased due to the effect of purse net of breeding fish. Pollution and eutrophication in the local lakes tend to be serious. It is effective that water environment indicators such as the concentrations of suspended substance and chlorophyll-a can be obtained by the use of multi-spectral remote sensing technology being applied to Taihu Lake and Dianchi Lake. However, the ability to inverse water environment under complex water quality or ecological conditions is limited with multi-spectral remote sensor owing to the wide wave band width. It could be a trend that hyper-spectral or super-spectral remote sensing technology is applied to complex water environment.