生态恢复前后的洪湖水质变化特征及驱动因素

湿地的水质状况反映了湿地生态系统的基本背景和质量,其水质的优劣直接关系到周边地区的经济发展和人民生活水平的提高。根据洪湖2000～2010年的水质监测数据,采用灰色模式识别模型对洪湖水质的时空变化特征及其原因进行了分析和评价。2000～2010年,洪湖水质综合指数位于2.08～3.58之间,以Ⅲ类和Ⅳ类水为主。总体上,洪湖不同年份的水质呈波动变化趋势。从空间变化来看,沿进水口—养殖区—开阔区—核心区—出水口的方向,洪湖水质逐渐好转。洪湖水质的变化主要受四湖流域地区工农业废水、生活污水等外源污染和湖内围网养殖的影响,其中,围网养殖是水质最主要的制约因素。为了使洪湖水环境更有利于人们的生产和生活,一方面应控制养殖面积,在适当控制渔业的前提下,开展植被恢复工作;另一方面,应大力控制上游地区工农业废水和城镇生活污水的排放,逐步恢复洪湖水体自净能力,实现洪湖水环境生态的可持续发展。

Water Quality Change Characteristics and Driving Factors of Honghu Lake before and after Ecological Restoration

Water quality can reflect the basic background and quality of wetland ecosystem.The water quality of Honghu Lake is directly related to the economic development of the surrounding areas and the improvement of people’s living standard.According to the water quality monitoring data from 2000 to 2010,with grey-mode identification model,we analyze its temporal and spatial variation characteristics and causes.The results showed that the comprehensive index of water quality was between 2.08 and 3.58 for the 11 years.The water quality mainly ranged between grade Ⅲ and grade Ⅳ.Generally,water quality of Honghu Lake rises first and then falls.There is some fluctuation change between different years.The spatial pattern of water quality showed a gradual improvement trend from inlet to aquaculture zone,open waters,core zone and outlet.The water quality is influenced by agricultural and industrial waste water from Sihu basin and enclosure aquaculture in the lake.The latter is the main restricting factor.In order to make the water environment in Honghu lake be favorable to people’s production and life.On the one hand,we should control the area of aquaculture and carry out vegetation restoration on the condition that fishery is controlled appropriately.On the other hand,we should vigorously control the discharge of agricultural and industrial waste water from the upstream region and town sewage,recover the self-purification of water bodies and realize the sustainable development of Honghu lake ecological environment.