title: Improving calibration of two key parameters in Hydrologic Engineering Center hydrologic modelling system, and analysing the influence of initial loss on flood peak flows.
abstract: Parameter calibration is a key and difficult issue for a hydrological model. Taking the Jinjiang Xixi watershed of south-east China as the study area, we proposed methods to improve the calibration of two very sensitive parameters, Muskingum K and initial loss, in the Hydrologic Engineering Center hydrologic modelling system (HEC-HMS) model. Twenty-three rainstorm flood events occurring from 1972 to 1977 were used to calibrate the model using a trial-and-error approach, and a relationship between initial loss and initial discharge for these flood events was established; seven rainstorm events occurring from 1978 to 1979 were used to validate the two parameters. The influence of initial loss change on different return-period floods was evaluated. A fixed Muskingum K value, which was calibrated by assuming a flow wave velocity at 3 m/s, could be used to simulate a flood hydrograph, and the empirical power-function relationship between initial loss and initial discharge made the model more applicable for flood forecasting. The influence of initial loss on peak floods was significant but not identical for different flood levels, and the change rate of peak floods caused by the same initial loss change was more remarkable when the return period increased.
authors.affiliation: School of Geographic Science, Fujian Normal University, Fuzhou, Fujian, 350007, China E-mail: cxwchen215@163.com.
authors.forename: Musheng
authors.initials: M
authors.lastname: Lin
authors.affiliation: School of Geographic Science, Fujian Normal University, Fuzhou, Fujian, 350007, China E-mail: cxwchen215@163.com.
authors.forename: Xingwei
authors.initials: X
authors.lastname: Chen
authors.affiliation: School of Geographic Science, Fujian Normal University, Fuzhou, Fujian, 350007, China E-mail: cxwchen215@163.com.
authors.forename: Ying
authors.initials: Y
authors.lastname: Chen
authors.affiliation: Dorset Environmental Science Centre, Ontario Ministry of the Environment, 1026 Bellwood Acres Road, Dorset, Ontario, P0A 1E0, Canada.
authors.forename: Huaxia
authors.initials: H
authors.lastname: Yao
mesh_terms: D002138:Calibration; D002681:China; D004784:Environmental Monitoring / Q000379:methods* / Q000706:statistics & numerical data; D055868:Floods; D005544:Forecasting; D057446:Hydrodynamics; D062070:Hydrology / Q000379:methods* / Q000706:statistics & numerical data; D008962:Models, Theoretical; D014872:Water Movements