Assessment of the different sources of uncertainty in a SWAT model of the River Senne (Belgium)

Although rainfall input uncertainties are widely identified as being a key factor in hydrological models, the rainfall uncertainty is typically not included in the parameter identification and model output uncertainty analysis of complex distributed models such as SWAT and in maritime climate zones. This paper presents a methodology to assess the uncertainty of semi-distributed hydrological models by including, in addition to a list of model parameters, additional unknown factors in the calibration algorithm to account for the rainfall uncertainty (using multiplication factors for each separately identified rainfall event) and for the heteroscedastic nature of the errors of the stream flow. We used the Differential Evolution Adaptive Metropolis algorithm (DREAM_(zs)) to infer the parameter posterior distributions and the output uncertainties of a SWAT model of the River Senne (Belgium). Explicitly considering heteroscedasticity and rainfall uncertainty leads to more realistic parameter values, better representation of water balance components and prediction uncertainty intervals.     

基于MIKE-ECOlab模型的英那河水库水质时空变化预测研究

城镇供水水源地水库的水质变化预测研究,对保证供水安全具有重要意义。文章以辽宁省英那河水库为例,利用MIKE-ECOlab模型模拟预测了丰水年、平水年和枯水年等不同工况下COD和氨氮两种主要污染物的时空变化规律。研究结论对英那河水库污染物运移规律研究、提高水环境保护水平具有重要的借鉴价值。     

Relationship between adjustment of low water level and utilization of water depth in Shashi Reach in middle Yangtze River

Hydrological, sediment, and bathymetric data of the Shashi Reach in the middle Yangtze River for the period of 1975–2018 were collected, and the characteristics of low water level changes and their impacts on utilization of water depth for navigation were investigated. The results showed that, during the study period, the Shashi Reach riverbed was significantly scoured and incised, with cross-sectional profiles showing overall narrowing and deepening. This indicated a strong potential to improve the water depth of the channel. The analysis of the temporal variation of in-channel topographical features showed that the Taipingkou diara underwent siltation and erosion, with its head gradually scoured and relocated downstream after 2008, and the Sanbatan diara continued to shrink and migrate leftwards. Low water levels with the same flow rate over the study period decreased. For instance, from 2003 to 2020, the water level at the Shashi hydrological station decreased to 1.37 m with a flow rate of 6 000 m³/s. Furthermore, the designed minimum navigable water level of the Shashi Reach was approximately 2.11 m lower than the recommended level. In terms of utilization of the channel water depth, continuous scouring of the river channel is expected to result in a reduction in discharge at the Taipingkou mouth, which will improve the water depth conditions of the channel during the dry season in the Shashi Reach. With several channel regulation projects, the 3.5-m depth of the Shashi Reach would basically be unobstructed. This promotes utilization of the shipping route from the Taipingkou south branch to the Sanbatan north branch as the main navigation channel during the dry season. Considering the factors of current water depth and the clear width limitation of the navigation hole at the Jingzhou Yangtze River Bridge, this route can still be favored as the main navigation channel with a 4.5-m depth during the dry season.     

基于ECMWF和WRF的嘉陵江流域面雨量预报精度评估

将降雨数值预报产品运用到水文预报中已经逐渐成为提高洪水作业预报的预见期的重要手段。为充分了解ECMWF(European Centre for Medium Range Weather Forecasts)和WRF(Weather Research and Forecasting model)2种数值天气预报产品对嘉陵江研究区面雨量预报的预报精度和误差分布,且为增强洪水预报精度的稳健性提供科学支持,采用TS评分、空报率、漏报率、正确率等指标,对嘉陵江地区7个气象分区内的2016年汛期面雨量预报结果进行了检验,分析了不同分区内各检验指标与预报时效的关系。结果表明:ECMWF数值预报产品和WRF数值预报产品均可用于该地区晴雨预报,且2种产品的预报精度随降水等级的增大呈增大趋势,随预报时效的增加呈减小趋势。综合而言,ECMWF数值预报产品对嘉陵江研究区的预报效果更好。     

黄河什四份子弯道冰期水流及冰塞特征研究

覆冰条件下,弯道水流固有的三维特性更为复杂,对河流弯道冰下水流特征及冰塞的研究有助于推进防凌减灾工作。依据2020年1月稳封期的原型观测数据,对黄河什四份子弯道冰下水流及冰塞特征进行了详细分析。结果表明,弯顶节点工程引起的回流是阻冰的重要条件,上游下潜的冰花因水动力不足及河势等因素影响发生堆积,冰塞在弯内形成并沿凹岸主槽逐渐向上游发展,同时,弯顶卡冰封河与下游较大的水流流速,促进了清沟的形成;入弯至弯顶区间,冰下水流流速垂线分布基本服从双对数分布规律;受凹岸冰塞及回流影响,纵向上,水流流速呈减小趋势,在弯顶附近开始恢复;径向上,河道主流被冰塞压迫并逐渐趋于凸岸,致使弯道主流易位,凸岸水流流速大于凹岸,清沟向凸岸偏移;弯道水流湍动能与雷诺应力主要在近底处存在较大的变幅,表明近底水流运动活跃,且二者大小与流速大小在径向与纵向分布上具有较好的一致性,受冰盖影响,水流湍动能沿水深近似呈"S"形分布,雷诺应力分布无明显规律。     

深圳抽水蓄能电厂球阀动水关闭试验研究

为验证深圳抽水蓄能电厂球阀具备动水关闭能力且不会产生有害振动进行了球阀动水关闭试验,获得不同负荷下球阀动水关闭实测各项动应力值及振动位移值。试验数据表明深蓄电厂球阀在不关闭导叶情况下能可靠关闭阻断上游来水,验证了在100%负荷动水关闭球阀最不利工况下,球阀混凝土支墩结构强度满足设计要求,球阀体系的振动位移是安全的,且对设备未产生有害变形及损坏。     

城市河流系统治理策略在鹅颈水生态修复中的应用

在简要介绍城市河流系统治理策略的基础上，详细论述其在鹅颈水生态修复中的应用。鹅颈水治理以流域为空间单位，准确把握河流主要问题，综合考量水资源、水安全、水环境、水生态、水文化，坚持工程和非工程措施并重，分阶段逐步实现洪水风险管理、外源污染控制、河流水质修复、河流生态系统恢复的目标。结果表明，鹅颈水目前已基本消除黑臭，水质逐渐提升至国家地表水Ⅳ类水标准。提出进一步加强河流生态系统恢复、优化管理制度、逐步建立全过程和全指标生态监测评估体系、实施弹性管理等鹅颈水系统治理措施。     

Application of large scale PIV in river surface turbulence measurements and water depth estimation

Large-Scale Particle Image Velocimetry (LSPIV) has emerged as a reliable technology to measure river surface flow velocity distribution and can be applied to estimate river discharge. Fewer studies have explored the capability of surface turbulence measurements using LSPIV. In this paper, LSPIV is applied to evaluate statistics of surface turbulence of a natural river. Turbulence measurements including velocity fluctuation, velocity spectra and the dissipation rate of turbulent kinetic energy (TKE) are validated by comparing with those measured by an Acoustic Doppler Velocimeter (ADV). Traditionally, estimation of stream discharge through LSPIV needs a secondary measurement to determine river bathymetry and water depth. A new method is presented here to demonstrate that for a fully developed and channel-controlled flow, the cross section geometry can be estimated from the combined measurements of surface mean velocity and the dissipation rate, following the Manning-Strickler formula. Therefore, river discharge can be estimated with LSPIV along with a calibrated Manning's roughness, without additional bathymetry survey. The proposed new method is applied to measure discharge in Milwaukee River (Milwaukee, Wisconsin, U.S.A.), which agreed well with data obtained from a nearby streamgage station.