Study On The Method Of Quantitative Analysis For Water Biological Service Functions In Polder Area

The southern polder area of China has fertility soil, variegated rivers and plentiful natural resources. As a special biological resource, water sustains the operations of all kinds of ecosystems in polder area, not only the elementary basic for human life and work, but also natural ecological structure, process and environment. Unfortunately during the past several decades, owing to the human activities, water surface rate in these regions kept reducing, and its biological service functions were dropping off, which lead to water ecological environment worsening. Today, with the target of sustainable development, people gradually sense to the importance of water biological service functions and its value. Science and technology do effect on water biological service functions, however they can not displace it. Therefore, the quantitative analysis helps to reasonably assess the value of water biological services functions, and promote sustainable development for economy of the society, it also has important significance in water resources sustainable utilization.According to the theory of ecosystem service functions, from the point of hydrology, ecology and environmentalology, seven aspects of water service functions were quantitatively analyzed, such as water supply, flood prevention, rainfall flow retardation for waterlogging control, air condition, water self-cleaning, aquatic products provisioning and biodiversity. The relation between each function and the water surface rate has been established, which made the constitution of quantitative analysis for water biological service functions established. Meanwhile, taking the Lixiahe polder area in Jiangsu province for example, by comparing different quantity of water biological service functions in different grade, the quantitatively analyze model were modified, which can provide better authority for quantitative analysis for water biological service functions in polder area.With the method of quantitative analysis for water biological service functions, the quantity of water service functions in Lixiahe polder area were estimated. By choosing the alternative method or the method of marginal cost, the efficient and consequential value of water functions could be obtained. All of these made the process of"quantity"convert to"value"completly, that intuitively reflect the economical value of water functions in Lixahe area and its important position in ecosystem.