The Ecosystem Health Assessment Based On Set Pair Analysis Model In Daliaohe Estuary

Estuary is located in the confluence of rivers and oceans. Estuarine ecosystem isinfluenced mutually by surface runoff, marine ecological environment, humanactivities and rainfall, etc. The rivers carried multifarious pollutants and sediment toestuaries. Several natural processes such as tides and ocean currents make the body ofwater in this area strenuous exercise and the pollutants were mixed seriously betweenthe sea and land. Developed economies, large population density and human activitiesin estuarine area create a certain extent harm to the estuarine ecological environment.Based on the above various factors influenced mutually, the environmental pollutionin estuarine area is serious increasingly and many problems, for example, ecologicaldegradation, biodiversity decrease, fisheries under serious threat, are followedimmediately. Those ecological environment problems which have affected the normaloperation of estuarine ecosystem function, should be resolved in a timely manner,otherwise they will react on the sustainable development of social economy.Currently, the health research of estuarine ecosystem attracts much attention ofdomestic and foreign scholars and research institutions, but has not yet formedcomplete and unified evaluation method and index system. In this paper, according tothe monitoring data of water quality, sediment and aquatic organisms about riversegment and off-shore areas of Daliao estuary in dry season in2009and the abundantseason and medium season in2010, filter indicators through principal componentanalysis.16indcators that are representative, relatively independ and reflect theestuarine ecosystem health are obtained, including dissolved oxygen, suspendedsolids, ammonia nitrogen, total nitrogen, total phosphorus, petroleum phytoplankton,zooplankton diversity index, biomass and diversity index of phytoplankton andzoobenthos biom-ass, benthic animal diversity index, heavy metals (Cu, Pb, Zn andCr) biohazard index. The evaluation index system covers water environmental quality, sediment quality and biological quality. Combining analytic hierarchy process andexpert’s advices get the weights of indicators. The set pair analysis model is used toevaluate ecological health status in differentseasons of Daliao estuary.The results show that in the dry season, abundant season and medium season, Daliaoestuarine health are all gradual deterioration from the entrance to upstream of Daliaoriver, the offshore area gradually improved since the entrance to the area which is faraway from the entrance.It also turns out that the health condition of estuarine riversection is better than estuarine offshore zone. The seasonal variations for ecosystemhealth condition in Daliao estury perform the abundant season> medium season> dryseason.Considering the complexity and vagueness about estuarine ecosystem environment,this article introduces the set pair theory into health assessment system in order toevaluate the health status of Daliao estuary ecosystem objectively, scientifically andcorrectly. The set pair theory provides the theoretical basis and method in the aspectof estuarine ecosystem health assessment, and also gives the basis for environmentalmanagement of estuaries. With the deepening of river health assessment studies, thereis still need to be further explored in the accuracy and availability of data, theuniformity of evaluation standards unity, etc.