ABSTRACT

The coefficient (k) of the $(-dQ/dt)-Q$ (discharge at time t) power-law relationship is typically computed after fixing the value of the exponent (α). However, recession analysis poses the challenge of finding a suitable α for a basin. Although many recent studies have suggested considering the median of the α distribution as the representative value, a purely logical reasoning for this has not been yet provided. In this study, we argue that there is no perfect approach to estimate α and that it should depend on the final objective. Recession flow prediction is considered the objective in this study. We employ a model to predict recession discharge for 408 USGS (United States Geological Survey), basins for a wide range of α values. Considering Nash-Sutcliffe efficiency as the indicator of model performance, we observed that the optimum value of α is substantially lower than the α median for most of the basins. Overall, our study establishes that there is no single value of $\alpha$ preferable for all practical purposes.

摘要

的系数 ( k )$(-d问/d吨)-问$（在时间 t 的放电）幂律关系通常在固定指数 (α) 的值之后计算。然而，衰退分析提出了为盆地寻找合适 α 的挑战。尽管最近的许多研究建议将 α 分布的中值视为代表值，但尚未提供对此的纯粹逻辑推理。在这项研究中，我们认为没有完美的方法来估计 α，它应该取决于最终目标。衰退流量预测被认为是本研究的目标。我们采用一个模型来预测 408 USGS（美国地质调查局）盆地的衰退排放量，这些盆地具有广泛的 α 值。将 Nash-Sutcliffe 效率作为模型性能的指标，我们观察到，对于大多数盆地，α 的最佳值远低于 α 中值。总的来说，我们的研究表明，没有单一的价值$\alpha$更适合所有实际目的。