The study of runoff formation in semiarid regions relies generally on the solution of Richards equations using numerical approaches such as those provided by Hydrus-1D. We demonstrate here that a Simple Analytical Method (SAM) could be easily applied to estimate areas under flooding risk, under different soil and rainfall conditions, without the need to run burdensome numerical models. The impact of antecedent soil moisture condition was expressed quantitatively, conferring to SAM a predictive capability based on a-priori information on soil properties, rainfall characteristics, and initial conditions. The SAM was applied to the Shikma catchment, in the center of Israel, to illustrate its capability to estimate the spatial distribution of time of runoff occurrence and runoff coefficient for a prescribed rainfall event. The results suggest that SAM can be used as part of early warning systems of flood risks. Radars, carried by satellites and drones, can be used to provide refined data on rainfall intensity and soil surface initial conditions. SAM could be then coupled with these remotely sensed data to improve runoff initiation and accumulation estimates, thus reducing the time interval required to reach operational decisions regarding potential floods and inundations, and related water erosion hazards.

中文翻译：

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估算径流产生和累积的简单分析方法


半干旱地区径流形成的研究通常依赖于使用数值方法（例如 Hydrus-1D 提供的方法）求解理查兹方程。我们在此证明，简单分析方法（SAM）可以轻松地应用于估计不同土壤和降雨条件下的洪水风险区域，而无需运行繁琐的数值模型。先前土壤湿度条件的影响被定量表达，赋予 SAM 基于土壤特性、降雨特征和初始条件的先验信息的预测能力。 SAM 应用于以色列中部的 Shikma 流域，以说明其估算指定降雨事件的径流发生时间和径流系数的空间分布的能力。结果表明 SAM 可用作洪水风险预警系统的一部分。卫星和无人机携带的雷达可用于提供有关降雨强度和土壤表面初始条件的精确数据。然后，SAM 可以与这些遥感数据相结合，以改进径流起始和累积估计，从而缩短就潜在洪水和淹没以及相关水侵蚀危害做出操作决策所需的时间间隔。