Study On Instream Ecological Flow Based On The Third Level Aquatic Eco-functional Zoning Of Liaohe River Basin In Liaoning Provice

Water resource is not only the important guarantee for region’s economic development, but also the key to the protection of ecological environment. The development of social economic lead to the increasing of water demand on instream(hydropower) and outer river.At the same time, the unreasonable water allocation of life, production, ecological destroyed the the waterdemand balance of natural ecological system of river, also leads to the lack of the minimum instream ecological flow.Environmental managers faced with how to restore, protect and maintain the river ecosystem health. Instream ecological flow is not only the basis to sustain the structure and function of water ecology of river, but also the important basis for carrying out water resources allocation and water environment management of watershed.In this paper, based on the third level aquatic eco-functional zoning of the Liaohe River Basin, the instream ecological flow of the main rivers of the Liaohe River Basin was studied.1) Using the hydrological data of Liaohe River Basin to hydrological analysis and draw the hydrologic frequency curve(Pearson type III distribution), that the Liaohe River basin runoff annual distribution of inter annual seasonal characteristics.Based on the results of the analysis with the climate, topography, vegetation and land use types and other factors, the suggestions for water ecological function manageent and construction ofeach sub basin were proposed2) The results were verified though the Tennant method that demonstrated the reliability of the two calculations, the adaptability of Monthly-guaranteed-frequency method is better than the fish habitat method, and the fish habitat method is more suitable for the large and little man-made influence catchment area. The result of the combining with the two methods features can reflect the difference among the instream ecological flow of different hydrological years from the perspective of hydrology by monthes and also emphasize the requirements of aquatic organisms to fish. And the scope of the proportion about inside and outside river water was confirmed based on the results.3) The value of different grades ecological flow ranges from 12% to 66.4% of the average natural runoff for years. Considered on the content, the maxutilization Liaohe River Basin water resources should not exceed 82%.Combined with the requirements of water quality and the threshold study of water resources utilizationand about Liaohe River Basin, ensure water ecological system health safe and stable,the proportion of outriver water utilization in Liaohe River(agriculture, industry, life) should be less than 33.6%.