Ecological Landscape Management Model And Effect Evaluation Of Mencheng Lake In Yongding River

The Yongding river is an important flood control barrier and ecological corridor in the southwest of Beijing.It has made great contributions to the construction and development of Beijing city.Due to water resource shortage,Sanjiadian reservoir has been no longer supplying the downstream river water since 2000.As a result,the river stream was dried up.Also,because of illegal mining of river sand,during spring and autumn season,sand was blowing everywhere,river ecological system was severely damaged,and caused great influence to the surrounding residents living environment.In order to improve the Yongding river ecological corridor and improve the surrounding environment,started from 2010,the construction of "four lake one line" project had been launched.With "governance the river with the amount of water,water is clean when there’s water,river is green when there’s no water" as the guiding ideology,the total length of 18 km of the river was reconstructed to solve the relationship between flood control and ecological landscape.Mencheng lake of Yongding River is located in the junction of Mentougou district and Shijingshan District,the downstream area of Sanjiadian reservoir,the total length of river channel is 5.24 km.In the ecological landscape reconstruction of Mencheng Lake,the demand of flood control function needs to be fulfilled first.Then the the river ecological landscape governance model would be meet,with “water,green,road,and facilities" as the main reconstruction element.River ecological landscape design include many aspects of water elements,such as water source,water quantity,water quality,water safety,plan form,vertical and horizontal connection of water,etc.Green elements mainly include the guiding ideology of planting,design principles,scope,standards,spatial analysis and plant selection,etc.Road elements include the classification,layout,material and connectivity of roads.Facilities elements mainly provide leisure entertainment,cultural display,convenient service venues and facilities to visitors.Through the reconstruction of "water,green,road,and facilities”,the presence of a waterfront space that meets the standard of flood control safety,good water quality,biodiversity,rich vegetation,convenient transportation,beautiful scenery and culture show was been finished.According to the " standard of the indexes and methods of river health assessment”,we also put forward the 5 evaluation indexes of river ecological landscape governance effect,which are: natural river formation system,ecological environment function system,renewable resources,recycling system,the humanism system,the intelligent monitoring system,and river ecological landscape treatment effect.These provide technical support for the planning and post evaluation of the project.Mencheng Lake was completed in early 2012.In the same year,it experienced and passed the "7.21" heavy rainfall test,the ecological landscape facilities of the river were safe and sound.After the reconstruction,the Mencheng Lake has become a good place for leisure,sightseeing,entertainment,fitness,waterside classroom activities.Good ecological environment and landscape effect of Mencheng Lake verified the feasibility of river ecological landscape governance model using "water,green,road and facilities" as the main construction element.The ecological landscape management model of the construction of "water,green,road and facilities" and 5 evaluation indexes of rivers,can provide guidance for the construction of the southern part of the Yongding River Plain,and provide reference for similar projects.