Research On Simplification Method Of Pipe Network Structure Based On Hydrological Characteristics Of Urban Watershed And Its Application

In the urban watershed,the pipe network system and the surface drainage system together form the city's double-layer drainage system,which plays an important role in the city's flood discharge process.However,in the modeling process,due to the limitations of the model,the pipeline network structure needs to be generalized.At present,the existing generalization methods still have some problems from the perspective of actual application results,which makes the rainwater collection process of the urban rain and flood model unreal.This paper combines the generalization of pipe network structure with the generalization of land surface,proposes a generalization method of pipe network structure based on urban hydrological characteristics and constructs an urban stormwater model suitable for urban watersheds,aiming to solve the generalized pipe network structure and terrain The rainwater harvesting process of urban rainwater model caused by landform is not real.The main research contents and conclusions include:1.Optimize the method of dividing watersheds based on the hydrological characteristics of urban watersheds: consider urban watersheds as a combination of natural watersheds and artificial hydrological facilities,and combine the actual watershed process to divide the watersheds based on the combination of macro and micro confluence After optimization,the divided catchment area can reflect the relationship of the urban double-layer drainage system,and has a good physical foundation,which is closer to the actual catchment area.2.Improve the surface generalization theory and method based on the urban river basin hydrological characteristics: refer to the difference between the core construction data DEM and the actual landform in the urban rainwater model of the urban rainwater urface is parameterized in the model.The generalized surface model can restore the interference and auxiliary effects of some artificial facilities on the water flow,and the parameterized underlying surface can better restore the flow and confluence process.3.The generalized theory and method of optimizing the pipeline network structure based on the urban hydrological characteristics: To restore the impact of building facilities that cannot be generalized on the model and the surface water catchment process of the urban watershed,and divide the buildings,roads and zoning Lines,boundary lines,and other artificial or natural facilities that have a greater impact on the catchment process are generalized in the surface model,and the underlying ssurface on the water flow,combined with the effect of the generalized surface model on runoff and the current rainwater drainage conditions,Generalize the network structure.The generalized pipe network structure and the surface model work together to restore the actual surface water catchment process and reflect the actual water catchment range of the municipal pipe network.4.Research on modeling application of the generalized method of pipe network structure based on urban hydrological characteristics: select a certain urban watershed to construct a model based on this research method.Compared with the model constructed by the existing generalized method,it is found that:(1)rain and flood In the model,the generalization of the pipe network structure has a great influence on the flood peak time and flood discharge of the overall rainwater system(20%),and has a great influence on the flood discharge and total discharge of the pipe network system(50%);(3)The new method of generalization of the pipe network can better reflect the actual pipe network in The role of the flood discharge process,the constructed rain flood model is more in line with the hydrological characteristics of the urban basin,its confluence process is more similar to the actual confluence process,and has certain reliability.The generalization method of rainwater pipe network structure based on urban hydrological characteristics provides methods and suggestions for how to generalize the rainwater pipe network structure in the urban rainwater research to make the rainwater model's water catchment process closer to the actual situation,and to provide terrain correction and watershed division Method reference.