Guoru Huang

Impact of Climate Change on Reservoir Flood Control in the Upstream Area of the Beijiang River Basin, South China

AbstractOne of the potential impacts of global warming is likely to be experienced through changes in flood frequency and magnitude, which poses a potential threat to the downstream reservoir flood control system. In this paper, the downscaling results of the multimodel dataset from phases 3 and 5 of the Coupled Model Intercomparison Project (CMIP3 and CMIP5, respectively) were coupled with the Variable Infiltration Capacity (VIC) model to evaluate the impact of climate change on the Feilaixia reservoir flood control in the Beijiang River basin for the first time. Four emissions scenarios [A1B and representative concentration pathway (RCP) scenarios RCP2.6, RCP4.5, and RCP8.5] were chosen. Results indicate that annual distribution and interannual variability of temperature and precipitation are well simulated by the downscaling results of the CMIP3 and CMIP5 multimodel dataset. The VIC model, which performs reasonably well in simulating runoff processes with high model efficiency and low relative error, i...

Application of the stormwater management model to a piedmont city: a case study of Jinan City, China

The stormwater management model (SWMM) was adapted and calibrated to Jinan, a typical piedmont city in China, to verify the large-scale applicability of the model to piedmont cities. Fourteen storms were used for model calibration and validation. The calibrated model predicted the measured data with satisfactory accuracy and reliability. A sensitivity analysis was then conducted to evaluate the impact of the model parameters; it showed that: (1) the model outputs were most sensitive to imperviousness and conduit roughness; and (2) infiltration parameters and depression storage play an important role in total runoff and peak flow. The urban drainage system of Jinan was assessed using urban design storms with the calibrated model, and the effects of engineered flood control measures were evaluated. The overall results demonstrate that SWMM is applicable on a large scale to piedmont cities.

Efficient Finite-Volume Model for Shallow-Water Flows Using an Implicit Dual Time-Stepping Method

AbstractAn implicit dual time-stepping method (DTS) is applied to a Godunov-type finite-volume model for two-dimensional (2D) shallow-water flows on unstructured grids to improve run-time efficiency. In this model, an implicit nonlinear lower–upper symmetric Gauss–Seidel (LU-SGS) solution algorithm is used as an inner iteration solver for DTS. To relieve the quantity nonconservation problem of DTS, a water quantity conservation correction method is presented. Five extensive test cases including two analytical benchmark cases and experimental and actual dam-break cases have been applied to validate the proposed model and to demonstrate its performance by comparison with an explicit scheme. The presented results show that DTS can reduce the run time from 55 to 78% without or with a minimal loss of accuracy. The overall performance demonstrates that the proposed model is accurate and efficient for simulating shallow water in practical applications.

A Coupled 1D-2D Hydrodynamic Model for Urban Flood Inundation

Hydrodynamic models were commonly used for flood risk management in urban area. This paper presents initial efforts in developing an urban flood inundation model by coupling a one-dimensional (1D) model with a two-dimensional (2D) model to overcome the drawbacks of each individual modelling approach, and an additional module is used to simulate the rainfall-runoff process in study areas. For the 1D model, the finite difference method is used to discretize the Saint-Venant equations. An implicit dual time-stepping method (DTS) is then applied to a 2D finite volume model for an inundation simulation to improve computational efficiency. A total of four test cases are applied to validate the proposed model; its performance is demonstrated by a comparison with an explicit scheme and previously published results (an extensive physical experiment benchmark case, a vertical linking example, and two real drainage cases with actual topography). Results demonstrate that the proposed model is accurate and efficient in simulating urban floods for practical applications.

Urban stormwater inundation simulation based on SWMM and diffusive overland-flow model

With rapid urbanization, inundation-induced property losses have become more and more severe. Urban inundation modeling is an effective way to reduce these losses. This paper introduces a simplified urban stormwater inundation simulation model based on the United States Environmental Protection Agency Storm Water Management Model (SWMM) and a geographic information system (GIS)-based diffusive overland-flow model. SWMM is applied for computation of flows in storm sewer systems and flooding flows at junctions, while the GIS-based diffusive overland-flow model simulates surface runoff and inundation. One observed rainfall scenario on Haidian Island, Hainan Province, China was chosen to calibrate the model and the other two were used for validation. Comparisons of the model results with field-surveyed data and InfoWorks ICM (Integrated Catchment Modeling) modeled results indicated the inundation model in this paper can provide inundation extents and reasonable inundation depths even in a large study area.

Assessing the Impact of Climate Change on the Waterlogging Risk in Coastal Cities: A Case Study of Guangzhou, South China

AbstractClimate warming is expected to occur with an increased magnitude of extreme precipitation and sea level rise, which leads to an increased probability of waterlogging in coastal cities. In this paper, a combined probability model is developed to evaluate the impact of climate change on waterlogging in Guangzhou by using eight climate models with four emissions scenarios [Special Report on Emissions Scenarios (SRES) scenario A1B and representative concentration pathway (RCP) scenarios RCP2.6, RCP4.5, and RCP8.5]. The copula method was applied to derive the bivariate distributions of extreme rainfall and tidal level. The uncertainty in the projected future temperature, extreme rainfall, sea level, and the combined extreme rainfall and tidal level probability were discussed. The results show that although there is a large uncertainty driven by both climate models and emissions scenarios in the projection of climate change, most modeling results predict an increase in temperature and extreme precipitat...