瞬时溃坝最大流量计算新通式推导及验证

为了计算瞬时溃坝最大流量,基于堰流与波流量相等原理,建立了瞬时溃坝最大流量与堰流关系,理论推导得到同一公式可以计算大坝全溃、横向局部溃坝、垂向局部溃坝及横垂向局部溃坝的瞬时最大流量的新通式,给出了该通式的基本和上限、下限及一般等通式。研究发现:瞬时溃坝流量与溃口堰坎类型有关,可以把瞬时溃坝最大流量、逐渐溃坝洪水或漫坝洪水的计算公式和相应系数统一到不同堰坎类型的堰流量计算中;而这些新通式相应系数的取值是被实验确认和经典著作肯定的,保证了系数取值的可靠和准确。这些新通式容易理解、形式简单、计算简便,参数取值可靠,把溃坝洪水计算的复杂问题转变为处理经典水力学的简单堰流计算。同时通过对比分析,充分论证了一般通式的合理性,并用国内外溃坝实例验证了计算方法和成果较科学、可靠、合理。     

娘子神泉流量评价

利用河流基流量与区域降水关系,结合泉流量偶测数据,评价不同保证率年份泉流量;以山西静乐县娘子神泉为例,讨论上述方法的应用过程与步骤,并探讨基流量偶测数据的代表性及其在泉水流量评价中的意义.     

时段平均输沙率计算方法探讨

以流量和含沙量在时段内呈线性变化，而输沙率应是二次函数为出发点，用积分的方法推导出时段平均输沙率的计算公式，认为采用这套公式计算日平均输沙率和日平均小于某粒径沙重百分数是合理和实用的。可以提高成果的准确性。     

流量过程线分割方法的分析探讨

对流量过程线分割方法进行了深入的研究，讨论了对基流问题的认识，给出了较合理的基流定义；分析探讨了几种常见的流量过程线分割方法以及存在的问题，并对这些分割方法从物理成因和水文产汇流规律等方面进行了比较研究。     

Sediment dynamics in the lowermost Mississippi River

There is much to be gained from investigating sediment dynamics in the lower Mississippi system, the largest river in terms of discharge and sediment load in North America. Such work can improve conceptual knowledge concerning downstream changes at the lower end of large river systems and can be applied to manage sediment diversions for wetland restoration in south Louisiana. Suspended sediment dynamics in the lowermost Mississippi River system in Louisiana are characterized using three approaches: (1) temporal changes in discharge-suspended sediment relationships showing interannual variations and the effects of floods over short timescales; (2) empirical relationships between discharge and suspended sediment variables at various locations; and (3) downstream changes in discharge-suspended sediment relationships. Interpretation of this data set is enhanced with other secondary data regarding processes, morphology, and bed materials.

Upstream, near Old River, LA, empirical relationships show nonlinearity, particularly in fine sediments, with decreased concentrations at highest discharges. During high discharge years, suspended sediment concentration peaks precede discharge crests by 40–85 days. The lead generally decreases with decreasing discharge maxima so that in low discharge years sediment peaks and discharge crests closely coincide in time. Downstream, near Belle Chasse, LA, fine bottom materials are resuspended and the timing of sediment peaks and discharge crests is coincident, regardless of flow magnitude. Conceptually, results suggest caution when generalizing about the relative timing of the sediment wave and flood wave and their downstream progression. These phenomena are influenced by local bed material and hydraulic conditions, and depend on the causative factors of sediment peaks. From an applied perspective, diversions should be managed differently depending upon where they are constructed along the river and upon the magnitude of the annual maximum flow. During high discharge years, when concerns for navigation and water supply are minimal, flow should be diverted on the rising limb upstream, near Old River, and during the discharge crest downstream near New Orleans.     

淮河入江水道归江控制河段行洪能力分析

淮河入江水道是淮河流域的主要行洪通道,承泄上中游70%以上的洪水入江。以淮河入江水道归江控制主要口门万福闸、太平闸、金湾闸近60年期间的实测资料,通过水位、流量、流速等要素分析淮河入江水道归江控制河段行洪能力的变化,以丰水年年最大流量和相应最高水位的关系曲线推求设计水位下的流量,并与设计流量进行比较。结果表明:(1)淮河入江水道归江控制河段行洪能力多年来无显著变化;(2)万福闸的实际行洪能力达到设计标准以上,太平闸、金湾闸基本达到设计要求。     

郁江南宁站水沙变化的回归分析

根据郁江南宁站1954～2001年的流量和输沙率资料，对流量和输沙率之间进行了回归分析，得出了多年平均月均流量～输沙率的相关性、各年月均流量～输沙率的相关性、各月月均流量～输沙率年际变化的相关性和年均流量～输沙率的相关性，分析了南宁站的水沙变化趋势，得出了两者变化趋势的规律。     

Fluvial Geochemistry through a Short-Duration, Tropical-Cyclone Induced Discharge event in the Burdekin River and Hann Creek, North Queensland, Australia

The chemical composition of river water integrates a number of factors such as weathering, land use, climate, vegetation cover and human activity that individually affect its chemistry. Short term variations may also be significant. The Burdekin River, NE Australia, is an example of a class of tropical streams which experiences two to four orders of magnitude variation in discharge in response to seasonal but erratic monsoonal and cyclonic rainfall. In these systems individual discharge events last for days to weeks. Given the inherent difficulty sampling these events published data on water chemistry (and thus calculated fluxes and global budgets) may tend to be biased to low flow conditions. One such discharge event in February 1996 has been investigated for its impact on the chemistry of the water. Major cations (Na, Mg, K, Ca) all decreased in concentration as the water level rose, as did the minor elements Sr, Ba and U. Some other trace elements, notably Rb, Cr, Pb and REE were enriched in the peak flow waters. The flux of all measured elements increased substantially during the seven days of the discharge event. Such short term but significant events will have a major impact on the annual fluxes of elements delivered to the oceans from the land and global discharge budgets may need to take them into account when refining databases in the future.     

基于生态水力学法的金沙电站最小下泄流量计算

最小下泄流量的确定是环境影响评价工作的重点,以金沙水电站为例,采用生态水力学法,在综合评判河段水深、流速、水面宽、湿周率、过水断面面积等水力参数以及水力形态要素的基础上,确定金沙水电站最小下泄流量,以满足下游河道鱼类生产繁衍的必要条件。     

青岛市环胶州湾各河流输沙特征分析

通过对青岛市环胶州湾各河流上的水文站历年含沙量、输沙量资料分析计算,推求出各河流的入海输沙量,并对输沙特征进行分析评价,最后得出以下以下结论:(1)从空间分布来看,胶州湾河流输沙主要来自胶州湾西北部和东北部。(2)河流属中沙河流。河道上游多年平均含沙量和输沙模数均大于河道中下游。(3)输沙量年际变化较大,最大年输沙量是最小年输沙量的518.7倍,且年降水量较大时,年入海水量也较大,年输沙量也较大。(4)河流悬移质颗粒特征为河流从源头到河口,泥沙粒径是不断减小。     

黄河内蒙古河段平滩流量与有效输沙流量关系

从水沙组合的角度出发,建立了基于水沙二维向量组合的频率统计方法,并在此基础上提出了有效输沙流量的计算方法。根据黄河内蒙古河段巴彦高勒站1954-2006年日水沙资料及汛后平滩流量资料,采用上述有效输沙流量计算方法计算得到了各年有效输沙流量及相应含沙量组合,进而分析了平滩流量与有效输沙流量及有效来沙系数之间的关系。结果表明,巴彦高勒站平滩流量调整分别受到包括当年在内的前期12年来水来沙条件的影响。     

基于HopField网络的排放口最优规划算法研究

针对排放口最优规划算法中存在非线性目标函数、约束条件过于复杂及“维数灾”等难点的困扰，提出了基于HopField网络的排放口最优规划算法，实例分析表明该算法具有较好的应用效果。     

王河煤矿矿井涌水量数值模拟及预测

针对岩溶充水矿井涌水量数值模拟中边界条件概化和非均质性刻画难题,采用分别建立区域模型和局部模型的方法解决边界概化问题,运用信息复合技术刻画岩溶介质的非均质性.以具有完整水文地质边界的荥巩矿区为计算区建立区域模型,以区域模型计算出的流量作为边界条件建立王河煤矿矿井涌水量模拟模型(局部模型).在充分分析钻孔、构造、突水、物探等资料的基础上,运用信息复合技术对煤矿充水含水层进行垂向和平面参数分区.在此基础上,利用GMS建立了精细的王河煤矿涌水量模拟模型.利用该模型预测了不同开采工作面的矿井正常涌水量和最大涌水量.结果表明,开采111070、113090、113110、113120工作面时,正常涌水量分别为490、350、560、590 m3/h,最大涌水量分别为690、490、790、830 m3/h.预测结果可为矿山设计部门确定开采方案、布置排水设备和制定防治水措施提供科学依据.      

用镭-226示踪胶州湾的海底地下水排泄

海底地下水排泄（SGD）是全球水循环的一个组成部分,其输送的溶解物质不仅参与海洋的生物地球化学循环,而且影响近岸海域的生态环境。为了评估胶州湾海底地下水排泄状况,通过建立胶州湾内海水中²²⁶Ra的质量平衡模型来计算海底地下水排泄通量。胶州湾海水中²²⁶Ra的源主要有河流的输入、沉积物扩散输入和地下水的输入,海水系统在稳定状态下,这几种源应该与湾内海水和湾外海水的混合损失达到平衡。除了将地下水输入作为未知项外,对其他源和汇逐个进行量化,计算得知：2011年9-10月胶州湾的海底地下水排泄通量为7.85×10⁶ m³·d^-1;2012年4-5月胶州湾的海底地下水排泄通量为4.72×10⁶ m³·d^-1。在此基础上,对地下水输入胶州湾的营养盐进行了评价。     

流量输沙率关系不确定度的分析

从误差传播及经验关系分析两条途径出发,分别获得流量输沙率关系不确定度。通过Ｆ检验,证明了所获成果的可靠性。本文分析对于流量输沙率关系不确定度控制指标的确定,以及流量输沙率关系的应用具有实际意义。     

长江源区1956-2000年径流量变化分析

利用Mann-Kendall趋势检验法对长江源区直门达水文站的资料进行分析,揭示长江源区年径流量在1956-2000年间呈微弱的减少趋势。结合流域气象资料分析,该时段流域内升温明显,最大可能蒸发量呈增加趋势,降水也呈微弱减少趋势。径流变化与降水变化基本一致,降雨-径流关系没有发生明显变化,表明1980-2000年降水量减少是该时段径流量减少的直接原因,温度升高有利于融冰融雪和降水形式的变化,但由于融冰融雪占径流补给的比率相对较小,该时段温度升高导致融冰融雪的增加不足以抵消降水量的减少对径流的影响。径流量季节变化分析,揭示长江源区春季径流呈增加的趋势,这可能与融雪过程提前以及融雪量增加有关。     

Empirical Relationships for Debris Flows

The assessment of the debris flow hazard potential has to rely on semi-quantitative methods. Due to the complexity of the debris-flow process, numerical simulation models of debris flows are still limited with regard to practical applications. Thus, an overview is given of empirical relationships that can be used to estimate the most important parameters of debris-flow behavior. In a possible procedure, an assessment of a maximum debris-flow volume may be followed by estimates of the peak discharge, the mean flow velocity, the total travel distance, and the runout distance on the fan. The applicability of several empirical equations is compared with available field and laboratory data, and scaling considerations are used to discuss the variability of the parameters over a large range of values. Some recommendations are made with regard to the application of the presented relationships by practicing engineers, apart from advocating field reconnaissance and searching for historic events wherever possible.     

甘肃省泥石流暴雨洪峰流量计算方法探讨

作为泥石流流量计算过程中一个关键的步骤,暴雨洪峰流量计算方法选取的准确与否直接关系到防治工程的经济合理性、技术可行性、安全可靠性等。根据勘查规范,同时结合不同的工程实例,对暴雨洪峰流量计算方法的选取,以及不同方法所得的计算结果进行了分析,对泥石流防治工程勘查设计有借鉴意义。     

多沙河流造床流量研究

在综述和分析前人有关造床流量研究成果的基础上,根据多沙河流的特点,提出了一种适用于多沙河流造床流量计算的水沙综合频率法.通过黄河、永定河水沙资料的分析,结果比较合理.     

Texas Coastal Hypoxia Linked to Brazos River Discharge as Revealed by Oxygen Isotopes

Hypoxic conditions in the coastal waters off Texas (USA) were observed since the late 1970s, but little is known about the causes of stratification that contribute to hypoxia formation. Typically, this hypoxia is attributed to downcoast (southwestward) advection of waters from the Mississippi–Atchafalaya River system. Here, we present evidence for a hypoxic event on the inner shelf of Texas coincident with the presence of freshwater linked to high flow of the Brazos River in Texas. These conclusions are based on hydrographic observations and isotopic measurements of waters on the inner shelf near the Brazos River mouth. These data characterize the development, breakdown, and dispersal of a hypoxic event lasting from June through September 2007 off the Texas coast. Oxygen isotope compositions of shelf water indicate that (1) discharge from the Brazos River was the principal source of freshwater and water column stratification during the 2007 event, and (2) during low Brazos River discharge in 2008, freshwater on the Texas shelf was derived mainly from the Mississippi–Atchafalaya River System. Based on these findings, we conclude that the Mississippi–Atchafalaya River System is not the sole cause of hypoxia in the northern Gulf of Mexico; however, more data are needed to determine the relative influence of the Texas versus Mississippi rivers during normal and low flow conditions of Texas rivers.