A Study of Rainfall-Runoff Response in a Catchment Using TOPMODEL

The simplicity of Topography-based hydrological model (TOPMODEL), as a way of reflecting the topographic controls on soil water storage and runoff generation, has become more attractive and more popular for land surface process study since digital elevation models (DEMs) have become widely available. In this paper, the effect of the topography index on soil water storage distribution, which is the key to TOPMODEL, is explained. Then a simple water cycle model for estimating other components of the surface water cycle is developed, which is implemented into the TOPMODEL to integrate the water cycle of the catchment. Using the output of a DEM from 100 m×100 m resolution data and a single flow direction algorithm, the index distribution function is calculated for a catchment (around 2500 km2 )in the upper reaches of the Yangtze River under different channel initiation thresholds. Finally, the daily and monthly rainfall-runoff response from 1960 to 1987 for the catchment is simulated with the TOPMODEL coupled with the simple water cycle model.

Coupling analysis of short-term weather and runoff in an arid lake basin of China

Changes in the weather will cause variations in the hydrological system.Arid areas,with fragile hydrological systems,are very sensitive to changes in the weather,so the coupling analysis of short-term weather and runoff in arid areas is of great significance.The Daihai Lake is a closed inland lake in an arid area of China.In this paper,Weather Research and Forecasting model mode-Hydrological module(WRF-HYDRO)is used to simulate the coupling of weather and hydrology in the Daihai Lake Basin.Regional optimization of WRF-HYDRO is carried out to determine the optimal parameters.The optimal WRF-HYDRO model is applied to couple the short-term weather and runoff in the Daihai Lake Basin to reproduce several rainstorm and flood events.It is found that runoff infiltration parameter(REFKDT)in WRF-HYDRO is the parameter that has the most severe effect on runoff in the Daihai Lake Basin.WRF-HYDRO can capture the rainstorm moment of the rainstorm events in the Daihai Lake Basin,especially the first rainstorm moment,and its simulation accuracy is good.WRF-HYDRO has a strong ability to capture flood peak,but there is a discrepancy between WRF-HYDRO flood peak and Soil Conservation Service Curve Number(SCS-CN)calculation result at the flood peak moment.The northern part of Zuoyun County should guard against the occurrence of flood disaster in wet season.The coupling of weatherand hydrology can not only make up for the lack of runoff data in arid basins,but also provide a basis for water resources management and disaster prevention and mitigation in the basins.

Influence of climate change on hydrological process in the upper reaches of Shiyang River:A case study of the Xiying River,China

Climate change is the dominant factor affecting the hydrological process, it is of great significance to simulate and predict its influence on water resources management, socio-economic activities, and sustainable development in the future. In this paper, the Xiying River Basin was taken as the study area, China Atmospheric Assimilation Driven Data Set(CMADS) and observation data from the Jiutiaoling station were used to simulate runoff of the SWAT model and calibrate and verify model parameters. On this basis, runoff change of the basin under the future climate scenario of CMIP6 was predicted. Our research shows that:(1) The contribution rates of climate change and human activities to runoff increase of the Xiying River are 89.17% and 10.83%, respectively. Climate change is the most important factor affecting runoff change of the Xiying River.(2) In these three different emission scenarios of SSP1-2.6, SSP2-4.5 and SSP5-8.5 in CMIP6 climate model, the average temperature increased by0.61, 1.09 and 1.74 C, respectively, in the Xiying River Basin from 2017 to 2050. Average precipitation increased by 14.36, 66.88, and 142.73 mm, respectively, and runoff increased by 15, 24, and 35 million m3, respectively.The effect of climate change on runoff will continue to deepen in the future.

Application of hydrological models in a snowmelt region of Aksu River Basin

This study simulated and predicted the runoff of the Aksu River Basin, a typical river basin supplied by snowmelt in an arid mountain region, with a limited data set and few hydrological and meteorological stations. Two hydrological models, the snowmelt-runoff model （SRM） and the Danish NedbФr-AfstrФmnings rainfall-runoff model （NAM）, were used to simulate daily discharge processes in the Aksu River Basin. This study used the snow-covered area from MODIS remote sensing data as the SRM input. With the help of ArcGIS software, this study successfully derived the digital drainage network and elevation zones of the basin from digital elevation data. The simulation results showed that the SRM based on MODIS data was more accurate than NAM. This demonstrates that the application of remote sensing data to hydrological snowmelt models is a feasible and effective approach to runoff simulation and prediction in arid unguaged basins where snowmelt is a major runoff factor.

Hydrologic Response of the Climatic Change Based on SWAT Model in Beijiang River Basin

[ Objective] The research aimed to establish SWAT distributed hydrologic model and analyze influence of the climatic change on runoff in Beijiang River basin. [ Method] Beijiang River basin as research object, SWAT model was used to simulate runoff in basin. Monthly water flow in Shijiao station from 1961 to 1980 was used to determine model parameter, while monthly water flow from 1981 to 1990 was used to verify. Setting 15 kinds of climate change scenarios, SWAT model was used to simulate influence of the future climatic change on runoff in Beijiang River basin. [Result] Simulated accuracy of the SWAT model was high, and it could be used to simulate runoff in Beijiang River basin. Under the situation of in- variable rainfall, temperature rise made that evaporation capacity increased, and runoff depth decreased. When temperature unchanged, rainfall increase made that evaporation capacity and runoff depth increased somewhat. [ Conclusion] The research could provide reference basis for water re- source management in Beijiang River basin.