Internationally, the occurrence and frequency of floods, along with the uncertainty involved in the estimation thereof, contribute to the practitioners' dilemma to make a single, justifiable decision when various design flood estimation methods are used. This article presents the further development of a Design Flood Estimation Tool (DFET) using Microsoft Visual Basic for Applications to assess the performance of event‐based design flood estimation methods in 48 gauged catchments in South Africa. The improved DFET proved to be an easy‐to‐use software tool for the rapid estimation and assessment of at‐site design floods in both gauged and ungauged catchments. In using a ranking‐based selection procedure, the Soil Conservation Service, Alternative Rational and Catchment Parameter methods provided the best estimates of the at‐site probabilistic flood peaks, while the Standard Design Flood method proved to be the least appropriate. Since the accuracy and uncertainty associated with each design flood method's key input parameters are unknown when applied in ungauged catchments, the incorporation of an ensemble event approach as part of the DFET calculation routines, is recommended. This will ensure that the key input parameters from an expected range of values are used to achieve probability neutrality between input rainfall and estimated runoff.

中文翻译：

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使用改进的基于事件的设计洪水估算工具评估现场设计洪水估算方法

在国际上，洪水的发生和频率以及其估算中涉及的不确定性，导致在使用各种设计洪水估算方法时，从业者难以做出单一，合理的决定。本文介绍了使用Microsoft Visual Basic for Applications来评估南非48个受调查流域中基于事件的设计洪水估算方法的性能的设计洪水估算工具（DFET）的进一步开发。事实证明，改进后的DFET是一种易于使用的软件工具，可用于快速估算和评估有轨流域和无流域流域的现场设计洪水。在使用基于排名的选择程序时，土壤保育局 可选的有理和集水参数方法可提供对现场概率洪峰的最佳估计，而标准设计洪水方法被证明是最不适合的方法。由于在无泄漏集水区中使用时，与每种设计洪水方法的关键输入参数相关的准确性和不确定性是未知的，因此建议将集成事件方法作为DFET计算例程的一部分并入。这将确保使用预期值范围内的关键输入参数来实现输入降雨与估算径流量之间的概率中立。当将其输入关键参数时，将其应用于非集水区时是未知的，因此建议将集成事件方法作为DFET计算例程的一部分。这将确保使用预期值范围内的关键输入参数来实现输入降雨与估算径流量之间的概率中立。当将其输入关键参数时，将其应用于非集水区时是未知的，因此建议将集成事件方法作为DFET计算例程的一部分。这将确保使用预期值范围内的关键输入参数来实现输入降雨与估算径流量之间的概率中立。