江汉平原湖域拆围监测及其生态环境效益估算研究 ——以洪湖为例

围网及网箱养殖是江汉平原湖泊水体环境污染的重要原因。湖北省湖库拆围大行动实施之后，湖泊围网拆除的成效及其生态环境效益值得关注和探讨。故以湖北省第一大湖洪湖为为例，首先基于改进的归一化差异水体指数（MNDWIn）、纹理分析等方法实现对湖泊拆围效果的快速监测；在提取拆围信息的基础上，根据洪湖水产养殖类型分担率及产排污系数法，对拆围的环境效益进行估算。结果表明：（1）洪湖拆围行动使湖内围网全部被拆除，共拆除湖内围网养殖区面积117.81 km2，自然水面面积增加110.49 km2；洪湖沿岸景观得到了明显改观，其中西部和北部地区拆围效果最为显著，而洪湖南部和北部的湖泊沿岸还存在部分待清理的非水体异质物。（2）洪湖拆围行动使排放到湖泊水体中的污染物减少1 265 284.38 kg，其中植物营养物总氮和总磷的浓度分别减少0.848、0.185 mg/L，这两项指标将由拆围前的Ⅲ类水质提升为Ⅱ类水质，湖泊水体富营养化问题得到较大改善；研究可为区域湖泊管理及流域生态环境保护提供快速监测技术支持和应用参考。

Lake Demolition Monitoring and Estimation of Ecological Environment Benefits in Jianghan Plain: A Case Study of the Honghu Lake

The purse seine and cage culture are primary inner lake pollutant sources in Jianghan Plain. After the implementing of the action of “purse seine demolition of lakes and reservoirs” in Hubei Province, it is quite necessarily to discuss and evaluate the effectiveness of the lake seine demolition and its ecological environment benefits. Therefore, a method was realized to rapidly monitor the effect of purse seine demolition, based on the modified normalized difference water index (MNDWIn), texture analysis, et al., taking the Honghu Lake, the largest lake in Hubei Province, as a case. Based on the monitored area changes information of purse seine, the environmental benefits of demolition were estimated, according to the pollutant share ratio of aquaculture type in the Honghu Lake and the production and discharge coefficient method. The results showed that: (1) Due to the action of “purse seine demolition”, the purse seines in the Honghu Lake have been completely removed. The area of purse seine culture has been removed by 117.81 km2, and the natural water surface area has increased by 110.49 km2. The coastal landscape of the Honghu Lake has greatly improved. The effect of demolition was most significant especially in the western and northern regions. However, there were still some non-water substances need to be cleaned in the north and south of the Honghu Lake. (2) The pollutants that discharged into the lake were reduced by 1 265 284.38 kg, in which the concentrations of total nitrogen and total phosphorus nutrients were reduced by 0.848 mg/L and 0.185 mg/L respectively. The water quality levels of these two indicators would be raised up to Class II from Class III before demolition, if there is not any other new pollutant source added. So, the eutrophication pollution of the Honghu Lake would also be greatly decreased. The study provides a rapid monitoring method to evaluate the effect of the implementations of the action of “purse seine demolition of lakes and reservoirs”, which can be applied to regional lake management and watershed ecological environment protection.