基于生态水深-流速法的河段生态需水量计算方法

在界定了生态流速和生态水深概念的基础上，提出了一种同时考虑河道本身参数(湿 周、糙率、水力坡度)和维持某一生态功能所需河流流量的水力学方法，避免了湿周法不能反映复式断面真实水位流量关系的缺点，并用于验证黄河上游小川河段生态需水量，同时用Tennant法作了对比。结果表明：用生态水深-流速法得到的小川河段生态流量优于Tennant法所计算的生态需水量，由于该方法考虑了生态流速和生态水深，故所得的结果符合实际情况。     

计算河段最小生态需水的生态水力学法

水文学法与水力学法对河道生态需水量采用的方法都比较宏观，没有仔细考虑水生生物水力生境需求。本文提出了计算河道最小生态基流量的生态水力学法，该法是通过目标水生生物适宜的水力生境确定河段最小生态需水量，文章对河道水力模拟，水生物生境描述等理论进行了研究，同时结合目标水生生物对水力生境的需求，重点研究水深、流速、湿周、水面宽、过水断面的面积、水面面积、水温等水力生境参数；急流、缓流、浅滩及深潭等水力形态的指标表现形式。本文提出的生态水力学法具有直观、定量的特点，为河道确定生态基流量提供了一套较具体、可行的方法。     

广西南宁市邕江河段生态流量研究

以广西南宁市邕江河段为例,采用湿周法、生态流速-临界水深法和综合法计算生态流量,并对计算结果进行合理性分析;通过Tennant法核实得综合法计算结果最优,由此确定广西南宁市邕江河段生态状况。结果表明,广西南宁市邕江河段生态流量为20.54~77.56 m³/s,比扣除供水和内河补水后剩余的流量小,满足邕江的生态流量;研究河段的生态流量占枯水期多年平均流量10%以上,表明该河段生态系统处于健康状态。研究结果可为流域的水资源开发、利用和修复提供理论依据,同时也为同类河段生态流量的推求提供参考。     

长江中下游河道生态流量研究

探讨了河道生态流量基本理论方法,针对长江中下游河道实际情况,选取宜昌站和汉口站作为控制性断面,采用改进河道湿周法计算长江中下游各河段最小生态流量,进一步根据鱼类产卵繁殖所需流速,估算了长江中下游各河段的适宜生态流量,并利用Tennant法对计算结果进行了分析评价。计算结果为,宜昌、汉口站断面的最小生态流量为2315m3/s3、124m3/s,分别占多年平均天然流量的16.7%、13.8%;宜昌、汉口站断面的适宜生态流量为8154.7m3/s1、6663m3/s,分别占多年平均天然流量的65.7%、73.6%。该研究结果为长江中下游的河流生态环境保护及水资源科学配置提供了参考。     

资料短缺平原河流的生态需水量计算——以通顺河武汉段为例

各类计算生态需水量的方法多需要长序列实测的水文或生境资料,无法直接适用于资料短缺的河流。在实测资料短缺的平原河流通顺河武汉段上布置10个典型断面,利用人为设定的多级试算流量来替代长序列实测流量,利用MIKE11软件模拟推求河道典型断面水力参数(河宽、水深、流速和湿周等)随流量的变化关系;在此基础上,依据平原河流滩槽明显的特点,选用水力学法中基于水力参数与流量间相关关系的湿周法和生态水力学法分别计算研究河段的生态需水量。计算结果表明,通顺河武汉段的河道基本形态得以维持和生物基本栖息地得以保障时的生态需水量应为26 m³/s。所提出的计算方案能较好地推求资料短缺地区平原河流的生态需水量,也可为类似河流的生态需水计算提供一定的参考。     

基于梯形模糊数的不确定性河道生态需水模型及其应用

针对目前各类河道内生态需水模型缺少不确定性方面的研究，本文将模糊数引入到河道内生态需水估算方法中，建立了模糊生态流速和模糊生态水力半径的概念。以抛物线型过水断面河道为例，在扩展原理的基础上，建立了流量与模糊生态流速、模糊生态水力半径的具体函数关系，提出了基于梯形模糊数的不确定性河道内生态需水模型，设计了算法流程，以杜柯河壤塘站为例进行了实例研究，计算并给出了不确定性河道内生态需水量的表达结果，还利用Tennant法对所建模型的实用性进行了验证，最后对计算结果的表达形式做了分析和解释。     

观音岩水电站生态流量研究

该文以观音岩水电站为例,根据河道断面曲线和水位~流量关系计算出各水力参数计算,然后用湿周法,Tennant法和R2-CROSS法对观音岩水电最小生态流量进行了分析计算。研究表明对于大型河流用Tennant法和R2-CROSS法计算的最小生态流量较接近且相对合理。     

赣江下游河道适宜生态需水量计算

受气候变化及人类活动的影响,赣江下游河道生产生活与生态用水的矛盾日益增加。本研究采用Tennant法和生态流量阈值法分别计算外洲断面生态需水量,并采用基于四大家鱼为生态保护目标的湿周法进行筛选比对,确定赣江下游适宜和较适宜的生态需水过程。结果表明：Tennant法和生态流量阈值法计算得到的年均适宜生态需水量分别为845.44m³/s、1 041.30m³/s,占外洲断面多年平均径流的40%左右;年均较适宜生态需水量为626.60m³/s、561.16m³/s,占外洲断面多年平均径流的27%左右,为赣江下游适宜生态需水量的预留提供依据。     

基于博弈论可变集模型的节水型社会建设评价

节水型社会建设评价的研究是制定相关节水政策与措施的基础。在节水型社会建设评价的过程中,既存在清晰信息,也存在模糊信息。根据这一特点,结合陈守煜教授的可变集理论,运用博弈论组合主观与客观权重,提出了一种基于博弈论可变集的节水型社会建设评价模型。利用该模型对洛阳市节水型社会建设情况进行评价,并与模糊综合评价法、模糊物元法、TOPSIS法和VIKOR法的结果相对比。结果表明:洛阳市节水型社会建设呈现一种发展向上的趋势,节水情况越来越好,可变集模型与其他评价方法相比具有更高的准确性与合理性。     

汾河中游河道生态流量分析

针对汾河中游河道生态环境受到破坏、生态流量不足的问题,选择兰村和赵城断面为研究对象,采用水文学及水力学等6种计算方法对比分析汾河中游河道的生态流量,并进行了保障性与计算结果合理性分析。结果表明：两个断面的生态流量有相同的变化规律,1、2及12月份生态流量很小,3月份生态流量较大,总体上汛期生态流量大于非汛期;在1996年之前,两个断面生态流量的年际保障率总体较高,1997-2008年保障率下降,2008年之后呈波动增大趋势;年内保障率波动变化,但兰村断面3月份保障率较高,赵城断面3月份保障率很低,应重点考虑3月份汾河中游河段的灌区用水及水库蓄水对下游河道生态系统的影响。对比6种方法的计算结果,逐月频率法不适用于汾河流域, 1、2、12月份生态流量推荐采用Tennant法计算结果,一般用水期的计算推荐Q_p法,汛期推荐年内展布法,3月份兰村断面推荐湿周法、赵城断面推荐Tennant法,推荐方法计算的逐月生态流量过程能够反映年内不同水期的丰枯变化,可为汾河中游生态修复工作提供参考。     

基于湿周法的河道最小生态需水量多目标评价模型

以湿周与流量关系为基础,建立了基于多目标评价方法的河道最小生态需水量估算模型,以湿周最大和河道流量最小作为栖息地保护和水资源开发利用的目标,采用理想点法求解,以增江下游麒麟咀站为例计算河道最小生态需水量,并将该模型的计算结果与斜率法和曲率法的计算结果进行了比较分析。结果表明:增江下游河道最小生态需水量阈值范围为20.8～26.3 m3/s,相应的平均流速范围为0.42～0.44 m/s;模型计算结果比传统的湿周法适用性更强,且能较好体现生态用水和经济用水的均衡发展。     

A multiple criteria decision‐making approach to estimate minimum environmental flows based on wetted perimeter

Minimum environmental flows in rivers provide a certain level of protection for the aquatic environment. The relationship between wetted perimeter and discharge can be used to define the minimum environmental flows by the slope method (SM), or curvature method (CM), especially for cases with poor understanding of the aquatic ecosystem. SM and CM derived inconsistent values of minimum environmental flows. It was not clear which method better defined minimum environmental flow. Moreover, the computation and optimization procedures are both time consuming and error‐prone, especially for complicated wetted perimeter–discharge relationships. In this study, flow regulation for rivers was regarded as a multiple criteria decision‐making problem, with the objectives of minimum river discharge and maximum wetted perimeter. Ideal point methods (IPMs) with the scaling coefficient r = 1 (IPM1) and r = 2 (IPM2) were used to solve this model to determine optimal environmental flows. IPM was simple in computation, especially when the wetted perimeter–discharge relationship was given as scattered data pairs. Meanwhile, it was applicable to a wider range of wetted perimeter–discharge relationship than SM and CM. Environmental flows estimated by IMP1 are the same as that by SM. The analytical results for environmental flows using SM, CM, IPM1 and IPM2 were compared for wetted perimeter–discharge relationship expressed as power or logarithmic function. It showed that CM is not a good method to define environmental flows. SM with unity slope and IMP1 were recommended. CM, SM and IPM were examined for the determination of environmental flows in a river in North Xinjiang, China. Environmental flows for different transects of the studying river reach were estimated to be 21% of the mean annual flow by SM or IPM1, which provided the satisfactory wetted perimeter, water depth and average velocity for aquatic organisms. Copyright © 2007 John Wiley & Sons, Ltd.     

抛物线形渠道的水力特性

通过积分和数值积分研究了n次抛物线形渠道湿周的计算,根据明渠均匀流理论研究了n次抛物线形渠道的正常水深;根据明渠临界水深和水跃共轭水深的理论,研究了n次抛物线形渠道的临界水深、弗劳德数以及水跃共轭水深的计算方法。给出了n次抛物线形渠道湿周、正常水深、临界水深、弗劳德数和水跃共轭水深的通用计算式,给出了水跃共轭水深的迭代式,证明了迭代式的收敛性,通过实例验证了计算式的正确性。本研究提出的n次抛物线形渠道的正常水深、临界水深、弗劳德数和水跃共轭水深的计算方法具有通用性,计算简单、精度高,可以应用于实际工程。     

吉林省伊通河生态需水量计算及分析

为研究吉林省伊通河生态需水量年内分配情况,采用流量历时曲线法分别对位于伊通河中下游的农安站及上游的伊通站的历史流量资料进行分析,得到伊通河农安站和伊通站的河道内最小生态需水量分别为4 693.66万 m³和303.52万 m³, 分别占年径流量的15.46%和4.80%;同时采用Tennant法和最小月流量平均法对伊通河最小生态需水量进行估算验证。Tennant法估算得到的最小生态需水量与流量历史曲线法较接近 。结果表明:在天然情况下,伊通河生态需水量的年内分配过程符合于实际水量分配过程,即多水时需水量多,少水时需水量少。农安段生态需水量可以有限地保护水生生物栖息地;而伊通段水生生物栖息地已经退化或贫瘠,需要采取措施对其进行保护治理。     

用改进湿周法计算河道内最小生态流量

在探讨总结国内外计算河道内最小生态流量(minimum instream ecological flow)方法的基础上,针对汉江流域的实际情况,选用改进湿周法对汉江上游石泉、安康和白河3个水文断面的最小生态流量进行定量估算。与Tennant法相比较,表明采用曲率湿周法计算的汉江上游河道内最小生态流量是比较合理的。计算结果为：石泉、安康、白河3个断面的最小生态流量依次为40,70,100 m3/s,分别占各断面多年平均天然流量的11.23%,11.08%,12.55%。     

河道束窄段对上游洪水过程特性的影响

为了研究束窄河段对洪水演进过程特征的影响,采用二维全水动力模型GAST模拟了束窄段河道洪水过程,通过理想河道和灞河上游实际河道分析了河道束窄程度与洪水特性间的定量关系。结果表明：束窄断面形状对洪水过程特征中水深、流速影响的大小依次为V形>U形>梯形>矩形。断面形状相同时,束窄程度越大对水深和流速影响越大。河道束窄段上游水位壅高,下游水位相对降低但流速更大。扩宽河道束窄段可以降低上游水位及上下游流速差。在“8·19”洪水下,灞河束窄河段束窄程度降低时(原河道束窄程度为64.4%,河道疏浚后束窄程度分别为55.6%、46.7%、37.8%),上游最大水深分别减小0.669、0.985和1.066 m,上下游流速差分别减小0.702、1.592、2.550 m/s。洪量越大则河道水位越高、流速越大,束窄程度变化对水位和流速变化的影响也越大。将“8·19”洪水进行缩放入流情况下,原始河道最大水深分别为2.177、2.778、3.618 m,束窄程度为37.8%时最大水深减小至1.866、2.367、3.175 m。通过分析不同束窄程度的束窄段河道洪水过程特性,可为束窄段河道防...     

河流最小生态基础流量计算方法研究

为了能够计算几何断面复杂、泥沙淤积、河宽大、水深浅的河道生态基础流量,本文以渭河关中地区的生态基础流量计算为例,通过综合水力学中的湿周法和R2CROSS法建立了一套简单、适合管理的最小生态基础流量方法——综合法。该方法计算出的5个站的生态基础流量占多年平均流量的比值都在10.8%～14.9%之间,满足生态基流的合理要求。通过与Tennant方法比较,结果表明:综合法计算确定的生态基础流量更为合理、是一种在管理上更值得推广应用的方法。     

Application of analytical solutions in trapezoidal compound channel flow

The accuracy of predictions using an analytical model for a lateral depth varying open channel flow can be affected by the friction factor and the dimensionless eddy viscosity. In this paper, different approaches to determine these two parameters are discussed by comparing analytical results with experimental data obtained from a symmetrical trapezoidal compound open channel. To reflect different hydraulic characteristics along the wetted perimeter, the trapezoidal cross‐section was divided into several sub‐sections, and the friction factor in each sub‐section was calculated with Manning's formula by adopting local hydraulic parameters. The wetted perimeters of main channel and side slope included the interface between panels to reflect the effects of the lateral momentum exchange. This approach is shown to be effective once the roughness coefficients and hydraulic radius in different sub‐regions have been determined. The results show that the friction factor is the major parameter affecting the accuracy of the analytical solution. The effect of dimensionless eddy viscosity on the precision of predictions is much smaller, which means that for practical applications, the dimensionless eddy viscosity can be determined empirically. Inclusion of a term for secondary flows in the model can improve the prediction, especially in the transition from main channel to the floodplain. A reasonable prediction of the lateral distribution of depth mean Reynolds' stress in this region is obtained. Copyright © 2010 John Wiley & Sons, Ltd.     

基于水力水文学法的大渡河上游生态流量确定

利用湿周法、Tennant法、Tessman法、逐月最小径流法分别计算大渡河上游的最小生态流量,并通过鱼类繁殖产卵所需的流量验证4种方法的合理性。结果表明,Tennant法、Tessman法、逐月最小径流法能保证足木足断面鱼类繁殖产卵所需的最低流量,大金断面4种方法均能满足。推荐3—8月采用Tennant法,9月至次年2月选择湿周法,计算得到的最小生态流量过程能够满足鱼类及栖息地保护的要求,又对人类取用水影响最小。     

Fatty Acid Profiles Distinguish Channel Catfish from Three Reaches of the Lower Kaskaskia River and its Floodplain Lakes

Despite the increasing use of fatty acids (FAs) as biomarkers in aquatic food web analysis, little information is available regarding differences in FA profiles of fish among habitat types in river–floodplain ecosystems. The objectives of this study were to (i) test whether the FA profiles of channel catfish (Ictalurus punctatus) differed among three reaches of the lower Kaskaskia River and its floodplain lakes, and (ii) to compare FA profiles among muscle, liver, and adipose fin tissues collected from these fish. Profiles differed significantly among sites, especially between upper and lower river sites, and between river channel and oxbow lake sites, suggesting differences in FA availability for channel catfish occupying different habitats and river reaches in the Kaskaskia River system. Specifically, the essential FAs 18:2n‐6 and 18:3n‐3 increased in catfish tissues from upstream to downstream reaches, which could reflect increased floodplain connectivity and decreasing impoundment effects downstream. Ratios of n‐3 to n‐6 FAs were higher in fish from oxbow lakes, perhaps suggesting increased use of autochthonous production in the floodplain relative to the main river channel. Muscle and adipose fin FA profiles exhibited similar location‐related trends, whereas liver FA profiles were markedly different from the other tissue types. These results suggest that adipose fin tissue samples may be a viable, less‐invasive alternative to muscle tissue for analysis of FA profiles in channel catfish. Our study supports the use of tissue FA profiles in identifying habitat utilization by channel catfish, and perhaps habitat‐specific energy contributions to riverine consumers. Furthermore, our work highlights floodplain habitat as a potential source of essential n‐3 FA and the associated importance of maintaining river–floodplain connectivity to support aquatic food webs. Copyright © 2014 John Wiley & Sons, Ltd.