Rainfall-runoff relationship in arid regions is unique and challenging to study. Studies for bridging the hydro-meteorological knowledge gap for planning, designing and managing water resources is therefore vitally important. The objective of this study is to develop a method for estimating unit hydrograph at reasonably finer time resolutions (10-min and 1-h) which can be easily adaptable by practitioners at sub-catchment levels, especially when the focus area is ungauged. Observed wadi-flow at 5-min interval and tipping bucket rainfall measurements at 1-min interval were obtained to cover 10 major watersheds in Oman. The deconvolution method was applied to derive the unit hydrographs (UHs) from wadi-flow and excess rainfall. Key catchment characteristics such as the watershed area, length of the main wadi and the length to the centroid of the catchment area were derived from digital elevation model (DEM) data. The whole study area was then divided into 515 sub-catchments with various shapes and sizes. A strong relationship was found between the wadi length and the length to the centroid of the catchment area (R2>0.89). This relationship was then adopted to simplify the classical Snyder method to determine UHs. Moreover, several parameters of the Snyder method were calibrated to the arid environment by matching the peak-flow, lag-time and three time-widths (75%, 50% and 30% of the peak-flow) of 10-min and 1-h UHs with physical characteristics of the watersheds. All developed relationships were validated with independent rainfall and wadi-flow events. Results indicate that the calibrated parameters in these arid watersheds are quite distinct from those suggested for other regions of the world. A marked difference was found between the 10-min UHs estimated by the S-hydrograph method and the deconvolution method. Therefore, it is concluded that a method depends on natural hydro-meteorological conditions would be more practical in arid region. The proposed methodology can be used for water resources management in arid regions having similar climate and geographical settings.

中文翻译：

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干旱区流域地貌特征估计合成单位水文线的空间回归方法

干旱地区的降雨-径流关系是独一无二的，研究起来具有挑战性。因此，在水资源规划、设计和管理方面弥合水文气象知识差距的研究至关重要。本研究的目的是开发一种以合理更精细的时间分辨率（10 分钟和 1 小时）估算单位水文过程线的方法，该方法可以很容易地被子流域水平的从业者采用，特别是当重点区域未测量时。以 5 分钟为间隔观测到的干河流量和以 1 分钟为间隔的翻斗式降雨量测量数据涵盖了阿曼的 10 个主要流域。解卷积方法用于从干河流和过量降雨中导出单位水文过程线 (UH)。主要流域特征，例如流域面积、主要河道的长度和到集水区质心的长度来自数字高程模型 (DEM) 数据。然后将整个研究区域划分为 515 个不同形状和大小的子流域。发现河谷长度与到集水区质心的长度之间存在很强的关系 (R2>0.89)。然后采用这种关系来简化确定 UH 的经典 Snyder 方法。此外，通过匹配峰值流量、滞后时间和 10 分钟和 1 分钟的三个时间宽度（峰值流量的 75%、50% 和 30%），将 Snyder 方法的几个参数校准到干旱环境。 -h 具有流域物理特征的 UH。所有发展的关系都通过独立的降雨和干河流量事件进行了验证。结果表明，这些干旱流域的校准参数与世界其他地区建议的参数截然不同。通过 S-hydrograph 方法和解卷积方法估计的 10 分钟 UH 之间存在显着差异。因此，可以得出结论，一种依赖于自然水文气象条件的方法在干旱地区更为实用。建议的方法可用于具有相似气候和地理环境的干旱地区的水资源管理。