Two new characteristic parameters for runoff computation

A method capable of estimating the hydrograph from a prescribed storm for a practical mild slope upstream catchment is proposed. This method makes use of two new characteristic parameters, andS, in conjunction with the kinematic wave equation to compute lateral inflows of the main stream of the catchment. The depth profile of overland flow at any instant within the catchment and hydrograph at any location can be easily found. Lag times for individual lateral inflows are then considered and are linearly combined to obtain the hydrograph at the outlet of the catchment or depth profile of the main stream at any instant. The validity of the excess rainfall-surface runoff linear relationship in this study has also been verified with Tatsunokuchiyama catchment, and it shows good results for this computed runoff.     

基于生态径流指标的水文情势变化评估新方法

基于流量历时曲线计算生态径流指标的方法存在诸多不足,也未形成相应的河流水文情势变化评估方法。采用流量过程线重新定义了月、季和年三种时间尺度的生态径流,构建了包含12个月生态盈余和12个月生态赤字的生态径流指标体系,提出了衡量这些指标在建库前后变化度的计算公式,基于月生态赤字发展了月生态风险评估方法,形成了一种河流生态水文情势变化评估方法。将其用于长江宜昌站,评估三峡工程在建库前后的生态水文情势变化。结果表明：重新定义的月、季、年生态径流之间消除了不一致性,香农多样性指数与年生态赤字的年际变化具有更高的相似度,变化度计算公式完全适用于衡量建库前后的变化程度,生态风险图使生态径流指标的实用性大为增强。     

基于原型监测的特高拱坝软弱带置换效果评价

特高拱坝蓄水后所受的总推力巨大,坝肩是关键受力部位,合理评估置换体加固效果将直接影响到工程的安全性和经济性。以原型监测为基础,采用实测值分析与理论推导相结合的方法,对小湾特高拱坝坝肩回填效果进行分析和评价。结果表明：接触带压应力过程线经历了增大和稳定2个阶段;接缝开合度过程线经历了温升压密、温降张开和稳定3个阶段,开合度与温度分段线性相关;围岩呈稳定态势,变形主要集中在前3个月,离洞口6m范围受开挖影响较大,16m为围岩松动圈范围。钢筋温度应力的理论值与实测值偏差较小。综合分析认为：回填体与围岩结合良好,有很好的传力性能;回填体及围岩应力、变形正常;回填效果好。     

ADCP在感潮水文站的使用

感潮水文站河流自然流态在潮水涨、落的影响下,顺逆变化,给流量测验带来很大影响。传统流速仪测量方法,测次多,误差大,为此采用声学多普勒流速剖面仪（ADCP）进行流速和流量的测量。比较了传统流速仪与ADCP测流的优缺点,介绍了ADCP的测量原理、安装、使用,详细分析了ADCP流速、流量比测和率定,并进行评定,以探索定点式ADCP测法在感潮水文站进行潮流量测验的可行性。黄屋屯水文站使用结果说明ADCP比较适用于感潮水文站的流量测验。     

流域汇流单位线时段转换应用分析

当流域汛期雨情报讯时段在特殊情况下出现变化时,流域汇流单位线必须事先进行时段转换后才能用于实际洪水预报。以实测水文原始数据为依据,根据示例流域在水文预报工作中的特殊需要,采用s曲线法对流域汇流单位线进行了实例转换和应用分析。分析成果符合相关行业规范精度标准,提出了分析成果的具体使用条件和应用范围,成果能够作为备选方法用于实际工作之中。     

浅谈经验单位线法在岩溶区洪水计算中的应用

由于缺乏实测水文资料,桂北、桂西片区域岩溶地区水利工程设计洪水计算一直都是个难题。介绍了采用经验单位线法计算岩溶地区设计洪水的方法及流程。     

基于综合单位线法的河道设计洪水参数推算

以深圳市观澜河支流白花河为研究对象,开展基于综合单位线法的设计洪水推算及参数选取研究.通过比较综合单位线法和推理公式法推算的各断面洪峰流量计算结果,说明综合单位线法的洪水计算成果偏于防洪安全.实例研究表明综合单位线法适合于类似地区的洪水计算.     

城市地面产流的试验研究

采用室内模拟降雨试验，对各种城市地面，如土地面，草地，混凝土地面及其多种组合的产流特性作了系统试验，分析了降雨强度与历时，土壤湿度与密实度，地面覆盖，不透水面积比例与位置等因素对径流系数和产流过程的影响，为城市水文规律的研究和模拟计算了提供了可靠依据。     

Optimal design of unit hydrographs using probability distribution and genetic algorithms

A nonlinear optimization model is developed to transmute a unit hydrograph into a probability distribution function (PDF). The objective function is to minimize the sum of the square of the deviation between predicted and actual direct runoff hydrograph of a watershed. The predicted runoff hydrograph is estimated by using a PDF. In a unit hydrograph, the depth of rainfall excess must be unity and the ordinates must be positive. Incorporation of a PDF ensures that the depth of rainfall excess for the unit hydrograph is unity, and the ordinates are also positive. Unit hydrograph ordinates are in terms of intensity of rainfall excess on a discharge per unit catchment area basis, the unit area thus representing the unit rainfall excess. The proposed method does not have any constraint. The nonlinear optimization formulation is solved using binary-coded genetic algorithms. The number of variables to be estimated by optimization is the same as the number of probability distribution parameters; gamma and log-normal probability distributions are used. The existing nonlinear programming model for obtaining optimal unit hydrograph has also been solved using genetic algorithms, where the constrained nonlinear optimization problem is converted to an unconstrained problem using penalty parameter approach. The results obtained are compared with those obtained by the earlier LP model and are fairly similar.     

单元嵌套网格产汇流理论

凭借"大数据"可以精细刻画降雨空间分布和下垫面空间变异性的优势,提出了"大数据"背景下考虑降雨空间分布和下垫面空间变异性对流域产汇流影响的计算方法,即单元嵌套网格剖分流域的方法。通过引入"网格水滴"的概念揭示了流域瞬时单位线的物理本质,对由RodriguezIturbe和Valdes所提出R-V地貌瞬时单位线理论进行补充,分析了等流时线法和单位线法的局限性,提出的单元嵌套网格产汇理论既克服了等流时线法和单位线法的缺点,也吸取了它们的优点,为在"大数据"支撑下统一等流时线和单位线法提供了可行性。