RESUMEN
In recent years, the occurrence of floods is one of the most important challenges facing in Hamadan city. In the absence/inefficiency of urban drainage systems, rainwater harvesting (RWH) systems as low-impact development (LID) methods can be considered as a measure to reduce the floods. In this study, three scenarios concerning the RWH from the roof surfaces are studied to evaluate the type of the harvested water on reducing flooding. In the first scenario, which indicates the current situation in the studied area, it is indicated that there is no harvest of the roof surfaces in the studied area. The second scenario is about the use of water harvested from the roof surfaces for household purposes. The third scenario also refers to the use of harvested water for irrigation of gardens. The simulation results of these three scenarios using the Soil Conservation Service (SCS) method in the Hydrologic Modeling System (HEC-HMS) model reveal that if the second scenario is implemented, the runoff volume decreases from 28 to 12% for the return period from 2 to 100 years. However, in the third scenario, this reduction in runoff volume will be 48 and 27% for return periods of 2 to 100 years, respectively. Therefore, the results of this study indicate that the use of harvested water can also affect the reduction on runoff volume.
Asunto(s)
Lluvia , Agua , Ciudades , Inundaciones , Hidrología , Movimientos del AguaRESUMEN
Precipitation and vegetation are two key factors affecting floods in the watershed. Quantitative evaluating their contribution to flood is of great scientific significance to vegetation construction and water resources management. Based on the geographic information data and hydrometeorological data from 1983 to 2014, we analyzed the characteristics of rainstorm and flood in Pengchongjian small watershed in red soil region of South China by Mann-Kendall test method, cumulative anomaly method and HEC-HMS model, and quantitatively evaluated the contribution rate of precipitation and vegetation variation to flood. The results showed that the rainstorm volume and total flood volume in Pengchongjian small watershed from 1983 to 2014 showed a non-significant upward/downward trend, respectively. HEC-HMS model had good simulation effect on single rainstorm flood, with the evaluation results being within the error range. The contribution rates of precipitation and vegetation variation of different rainstorm floods were different with respect to the total flood volume or to the peak flow. The average contribution rate of precipitation and vegetation variation to the total flood volume was 66.5% and 33.5%, while to the peak flow was 58.9% and 41.1%, respectively. Our results could provide scientific basis for flood evaluation, vegetation construction and comprehensive control of soil erosion in small watershed.