General Thinkingon the Management of Blue Algae Outbreak in the Taihu Lake,the Chaohu Lake and the Dianchi Lake

Among the Chinese lakes with the problem of eutrophication, the Taihu Lake, the Chaohu Lake and the Dianchi Lake have the worst cases of blue algae outbreak, which happen every year. Other lakes also have problems of blue algae outbreak at various degrees. However, some lakes don＇t have such problems. Practices have shown that through comprehensive management, the problem can be basically eliminated or significantly alleviated. ＂Water bloom＂ and blue algae outbreak have different connotation. The major factors affecting blue algae outbreak are sources of pollutants and ecological environment. Experiences are summed up and a new thinking on its management is developed： resolving the problem of blue algae is fundamental to lake management and development goals should be clearly set forth so as to eventually build a healthy aquatic ecosys- tem. The problem of blue algae can＇t be fully tackled by solely relying on the management of eutrophication but only by combining efforts of reducing the amount of blue algae and the management of eutrophication. The number of reduced blue algae should be larger than that of naturally prolifera- ted algae so as to alleviate and eliminate the problem of blue algae outbreak. Various engineering and technical measures and relevant protective procedures should be carried out in a scientific and proper manner. The total amount of nitrogen and phosphorous entering the lake either from point-source or non-point source pollution should be substantially reduced. Controlling the source of pollution and intercepting pollutants are the bas- ic measures. Wastewater treatment plant is the largest point source pollution in the future and adequate plants should be built with improved emission standards. Meanwhile, other measures including fishing out blue algae, diverting water, dredging, ecological restoration and expanding reed zone, should be implemented to alleviate the problem of eutrophication and eventually eliminate the problem of blue algae outbreak.

From systematicness to complexity: Fundamental thinking of mega-project management

Mega-projects are characterized by their large-scale investments, long life-cycle, and extraordinary levels of organizational, technological, and environmental complexity （Flyvbjerg, 2017）. They are naturally regarded as large, coupled human, and physical systems consisting of coupled sub-systems linked through flows of human, information, and matter; these systems evolve through time （Bakhshi et al., 2016; Kiridena and Sense, 2016）. Not about let systems be, engineering refers to ＂making things happen＂ with convergence, optimum design, and operation consistency （Mihm et al., 2003; Ottino, 2004）. Specially, mega-projects, which are regarded as typically artificial complex systems, are composed of elements with different properties; connections among those elements change invariably. Mega-project management is proposed to analyze and deal with complexity （Sheng, 2018）.

Systems research helping to meet the needs and managing the trade-offs of a changing world

Facing the challenges of an increasing world population, a changing climate and ever depleting resources, agricultural intensification （Keating et al. 2010） is one of the few options for meeting the demand of food security. It is necessary to apply a dynamic and systematic approach to effectively man- age the complex agri-eco production and green processing systems. Indeed, farming systems approach for appropriate technology development and simulation modeling is a result of adopting the system thinking by the agricultural research community （Norman et al. 1995）.