Investigation of extreme hydrological events are necessary for planning and designing hydrological structures. In this study, we examine and project two hydrological extremes of drought and wet conditions over the north and eastern regions of the country. A statistical procedure of the Reconnaissance Drought Index at the annual time scale was used to combine the monthly rainfall and temperature data for the assessment of extreme drought and wet events. These hydrological extreme events were combined with Index-Drought Procedure using L-moments to obtain study results. Homogenous regions were satisfied for both the extremes based on statistical measures. Two statistical tools were used to select suitable probability distributions in the form of Generalized Pareto and Pearson Type-III distributions to discuss drought risk and wet conditions in the regions. Secondly, regional projections of drought risk and wet conditions were performed based on regional quantiles at different interarrival periods which show greater chances of the wet condition in region one while drought risk in region two. Lastly, at-site projections were carried out for all the included sites for both extremes at various interarrival periods using the suitable probability distributions. Both at-site and regional projections show greater similarity at lower while uncertainty at higher interarrival periods. As droughts and wets cover, a large area, therefore, regional results are more functional and better for regional planning and development programs. These statistical projections will help planners of water resources management and hydrological extremes in the study area.

对于计划和设计水文结构，必须对极端水文事件进行调查。在这项研究中，我们检查并预测了该国北部和东部地区干旱和潮湿条件的两个水文极端事件。使用年度时间尺度上的侦察干旱指数的统计程序来组合每月的降雨和温度数据，以评估极端干旱和潮湿事件。将这些水文极端事件与使用L矩的干旱指数程序结合起来，以获得研究结果。根据统计指标，均质地区对两个极端都满意。使用两种统计工具以广义Pareto和Pearson III型分布的形式选择合适的概率分布，以讨论该地区的干旱风险和潮湿条件。其次，基于不同到达间隔时期的区域分位数对干旱风险和湿润条件进行区域预测，这表明区域一出现湿润条件的机会更大，而区域二出现干旱风险。最后，使用合适的概率分布，在不同的到达间隔期间，对所有包含的站点进行了两种极端情况的现场预测。现场预测和区域预测在较低的到达时间都显示出更大的相似性，而在较高的到达间隔期则显示出不确定性。因此，由于干旱和湿气覆盖的面积很大，区域结果对于区域规划和发展计划更具实用性和更好性。这些统计预测将有助于研究区域水资源管理和极端水文学的规划者。