Flood simulation and regulation study of the Xihe drainage area in Jincheng city

Underground drainage pipeline network as the main drainage channel has direct impact on flood control and waterlogging capacity． The Xihe drainage area in Jincheng city, Shanxi province is studied in this work． The drainage efficiency of pipeline network system in the district is analyzed and surface waterlogging characterized by simulation of rainstorm and flood processes． Different schemes for detention facilities on flood control are compared． For a rainstorm with 10-year return period, proportion of nodes with overflow duration exceeding 1.0 hour is found to account for 70.31% of the total nodes, proportion of pipelines with overload duration longer than 0.5 hour accounts for 44.74% of the total pipelines． For rainstorms with different return periods, duration of water accumulation exceeding 70% of the total area lasts more than 1.0 hour, this indicates significant drainage pressure on the pipeline network． Detention facilities show different reduction effects on surface flood． Detention facilities in the upper and middle reaches could relieve drainage pressure downstream． However, impact of different pump station start-up water levels on flood control is relatively limited． Detention facilities show more significant mitigation effect in areas with greater water depth, with reduction rate in areas with water depth exceeding 0.4 m being 42.05% and 28.52% for rainstorms with 10 and 50 years of return period, respectively．