Abstract
Population growth and land use modification in urban areas require the use of accurate tools for rainfall-runoff modeling, especially where the topography is complex. The recent improvement in the quality and resolution of remotely sensed precipitation satisfies a major need for such tools. A physically-based, fully distributed hydrologic model and a conceptual semi-distributed model, forced by satellite rainfall estimates, were used to simulate flooding events in a very arid, rapidly urbanizing watershed in Saudi Arabia. Observed peak discharge for two flood events was used to compare hydrographs simulated by the two models, one for calibration and one for validation. To further explore the effect of watershed heterogeneity, the hydrographs produced by three implementations of the conceptual were compared against each other and against the output of the physically-based model. The results showed the ability of the distributed models to capture the effect of the complex topography and variability of land use and soils of the watershed. In general, the GSSHA model required less calibration and performed better than HEC-HMS. This study confirms that the semi-distributed HEC-HMS model cannot be used without calibration, while the GSSHA model can be the best option in the case of a lack of data. Although the two models showed good agreement at the calibration point, there were significant differences in the runoff, discharge, and infiltration values at interior points of the watershed.
Highlights
Published: 16 April 2021Hydrologic models are used to solve a range of specific problems in the management and development of water and land resources, including flood simulation and prediction, aquifer recharge management, runoff estimation, and drainage network design (e.g., [1,2,3]).The uncertainties inherent in these models can be reduced with the availability of accurate input and watershed data [4]
The storm event of 13 February 2010 with total rainfall accumulation of 55 mm reThe storm event of 13 February 2010 with total rainfall accumulation of 55 mm resulting in a peak discharge of 431 m3 /s and a flow depth of 1.6m measured at a point sulting in a peak discharge of Uranah
Notused a fully disbrate both the is not a fully distributed tributed model, each IMERG rainfall grid value was input to the HEC-HMS as point model, each at rainfall grid value input to the as whole point observation observation the grid center, and this was process was applied over the watershed
Summary
The uncertainties inherent in these models can be reduced with the availability of accurate input and watershed data [4]. Hydrologic models include lumped models, semi-distributed models, or fully distributed models [5]. These models can be classified based on the model formulation as empirical or physically-based models with conceptual formulations typically used in lumped models and physical equations in the other two types [6]. The application of lumped models is limited to gauged watersheds not undergoing significant change in their conditions, and they have to be calibrated using significant observational data [7]
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