基于降雨预报信息的梯级水电站不确定优化调度研究Ⅱ：耦合短、中期预报信息

基于聚合分解思想将梯级水库群聚合为“虚拟单库”,降低了随机动态规划（SDP）模型的计算量,从而使SDP模型可以考虑更多预报信息。为了更近一步充分利用预报信息和降低预报信息不确定性对调度的影响,将降雨预报和径流预报的不确定性考虑为随预见期延长而不断增加的过程。首先将浑江流域的10d预报径流划分为前5d和后5d,并将前5d预报径流视为较准确的部分,而后5d预报径流视为不确定性较大部分;然后建立短、中期径流预报信息相套接的分段聚合分解贝叶斯随机动态规划（Two-Step-BSDP,TS-BSDP）,为浑江梯级水库群制定前5d、后5d和10d的预报调度图;最后以5d为调度时段分别决策未来5d发电和10d发电计划。模拟调度结果表明,该模型中决策长度为5d的滚动决策具有更好的效果,该决策方式充分地利用了预报信息并有效地提高了发电效益。     

径流贝叶斯概率预报在水库发电优化调度中的应用

为了充分考虑降雨、径流预报的不确定性和降低水库发电调度模型的复杂性,采用贝叶斯概率水文预报系统(BFS)耦合降雨预报的不确定性和径流预报模型本身的不确定性来定量描述径流预报的不确定性,发布径流确定性预报、概率预报和概率预报期望值;结合随机动态规划(SDP)模型和贝叶斯随机动态规划(BSDP)模型来制定发电调度图;以浑江桓仁水库流域为背景,采用美国国家天气局的全球预报系统(GFS)发布的10d降雨预报信息作为预报模型输入,模拟桓仁水库的发电调度过程。模拟结果表明基于径流贝叶斯概率预报的水库发电调度能有效提高水库的发电效益和保证率。     

基于降雨预报信息的梯级水电站不确定优化调度研究I：聚合分解降维

基于降雨预报信息的水库群预报优化调度有利于提高水库群水电站发电效益。本文首先采用聚合分解思想将梯级水库群来水量和库容聚合等效为单库,从而简化水库群径流过程的描述和降低高维计算空间,使随机动态规划模型（SDP）在梯级水库群的应用中可以考虑更多的信息来提高模型效率;然后在径流预报中考虑美国全球预报系统（GFS）发布的未来10d降雨预报信息,来提高中期径流预报精度;最后在考虑径流预报不确定性的基础上建立了聚合分解贝叶斯随机动态规划模型（AD-BSDP）。同时与传统调度图、聚合来水量的随机动态规划模型（AF-SDP）和聚合来水量、库容的聚合分解随机动态规划模型（AD-SDP）进行对比分析,其结果表明,考虑预报信息不确定性的AD-BSDP模型比其他模型具有更高的效率和稳定性。     

基于数值预报模式的柘溪水库流域径流预报系统

水库的优化调度运行需要依赖预报准确率高、预见期长的径流预报结果。现有的柘溪水库流域径流预报系统由于未考虑水库流域未来时段的降水过程,径流预报的预见期和准确率无法满足汛期优化调度的要求。为此,在分析柘溪水库流域的水文和气候特征基础上,提出了数值预报模式和水文模型的耦合预报框架,设计了基于数值预报模式的柘溪水库流域径流预报系统架构,阐述了系统的主要功能与逻辑结构。通过系统的应用,可为提高汛期洪水的利用率、减少弃水、提高发电和防洪效益提供重要决策支撑。     

聚合分解随机动态规划模型在梯级水库群发电调度中的应用研究

本文首先采用聚合分解思想将梯级水库群来水量和库容聚合等效为单库，从而简化水库群径流过程的描述和降低高维计算空间，使随机动态规划模型（SDP）在梯级水库群的应用中可以考虑更多的信息来提高模型效率；然后在径流预报中考虑美国全球预报系统（GFS）发布的未来10天降雨预报信息，来提高中期径流预报精度；最后在考虑径流预报不确定性的基础上建立了聚合分解贝叶斯随机动态规划模型（AD-BSDP）。同时与传统调度图、聚合来水量的随机动态规划模型（AF-SDP）和聚合来水量、库容的聚合分解随机动态规划模型（AD-SDP）进行了对比分析来验证模型的有效性，分析结果表明考虑预报信息不确定性的AD-BSDP模型比其他模型具有更高的效率和稳定性。     

考虑预报不确定性的水风光互补系统两阶段决策研究

【目的】水风光资源长期预报精度有限,如何应对风光出力和径流的不确定性是充分发挥多能源协同优势的关键,为此,提出考虑预报不确定性的水风光互补系统两阶段决策方法。【方法】将互补系统长期调度多阶段决策划分为包含面临时段和余留期的两阶段决策,通过余留期能量曲面表征余留期不同库容条件与未来风光出力及径流所能产生的发电效益;讨论不同预报水平下水风光资源预报信息的利用方式,提出余留期能量曲面确定方法,并分析预见期利用长度对互补系统效益的影响,确定最佳预见期利用长度;以基于调度图模拟的互补系统调度结果作为对照,评估不同预报水平下两阶段模型的适用性。【结果】选择雅砻江下游水风光互补系统进行实例研究,结果显示：(1)两阶段模型中基于径流序列映射模型的预报信息利用方式能较好地表征余留期效益;(2)随着两阶段决策模型预见期利用长度的增加,预见期的边际效应显著降低,互补系统最佳预见期利用长度为3个月;(3)与调度图相比,两阶段模型推迟水库蓄水和消落时机并加深消落程度,使得发电效益和出力可靠性在预报水平较高时整体高于调度图。【结论】结果表明：两阶段决策模型能够灵活结合多个预见期的预报信息,实现有限预报信息下的互补...     

闹德海水库洪水预见期分析

文章通过分析闹德海以上流域较大水年的次降雨,用降雨径流预报和河段预报2种方法来分析闹德海水库洪水预见期,从而为水库合理调度提供科学依据。     

水电厂气象水文综合预报调度模型的建立与应用

水电厂气象水文综合预报调度模型整合了降雨预报方案、中长期水文预报方案:洪水预报方案、水库优化调度方案等现有模型系统.降雨数值预报接入水库预报调度系统后,延长了来水预报预见期,结合文中研究的优化调度模型,使水电厂能够提前调整发电计划、调度方案,增加了水电厂的发电效益和水库的防洪减灾社会效益.     

浑江流域梯级电站GFS预报结果应用分析

水库优化调度的关键在于径流预测的预见期。目前天气预报中预见期最长的是美国"全球预报模式(Global Forcasting System"),预见期可以达到15天。文中以浑江流域梯级电站为例,分析探讨了GFS预报准确率与实际应用。从实际应用情况看,在梯级电站水库调度工作中应用GFS预报信息,机组可以提前加大出力,减少后期弃水,效益比较明显。     

基于Transformer的智能洪水预报模型及其应用研究

万安水库是赣江流域以发电为主的大型控制型水库,其洪水预报准确性将影响赣江流域的防洪以及发电调度决策。基于Transformer网络建立入库洪水预报模型,对万安流域不同区域分区设计三种预报方案,经实际洪水预测结果表明,输入降雨和径流数据越完整,Transformer模型可以较好模拟入库洪水过程,达到较好的水文预报准确度,是大型流域洪水实时预报的有效工具。     

Call for Papers

正As the eldest and most distributed professional journal of water industry,Water Wastewater Engineering(W WE)gained very wide acceptance from the colleagues working in this field in this country since start publication in 1964.Now it is administrated by the Ministry of Construction of the People’s Republic of China and sponsored by the China Civil Engineering Society etc.     

地下厂房施工过程的三维非线性数值模拟分析

根据冗各电站地下厂房开挖支护的施工顺序,以隐式杆单元模拟锚杆,以壳单元模拟混凝土喷层,采用三维非线性有限元技术,对洞室群的开挖支护动态过程进行了模拟计算。通过三维非线性有限元计算分析得到:洞室群动态开挖过程中围岩应力变形的分布规律,围岩塑性区的发展规律,锚杆受力变化情况。计算结果表明:整个开挖过程中,洞周围岩位移变化规律正常,量值较小,塑性区主要分布在洞室周边,围岩稳定性较好;但在洞室交叉口处围岩的变形较大,出现较大范围的塑性区,在此基础上提出了支护措施优化方案,并对优化方案的效果进行了评价。     

Serial discontinuities in a Rocky mountain river. I. Distribution and abundance of plecoptera

Samples were taken year-round at eleven sites along the altitudinal profile (2900-1400 m a.s.l.) of the Gunnison River, a 329 km tributary of the Colorado River, to document the distribution of the Plecoptera and to evaluate responses to hypolimnial-release dams in the headwaters and middle reaches. Twenty-two species were present, with the greatest species richness occurring in an unregulated segment upstream of the middle reach dams; average nymphal biomass over the study period (175 organisms, 395 mg dry mass m^?2) was also greatest in this segment. Only four species (58 organisms, 48 mg m^?2) were present in the tailwaters of the headwater dam and values were greatly reduced (nine species; 35 organisms, 180 mg m^?2) below the middle reach dams. The stonefly community recovered ca. 80 km downstream from the last dam (15 species; 244 organisms, 250 mg m^?2), apparently in response to natural resetting of environmental conditions corresponding to those above the middle reach dams. At the most downstream site (11) only four species (four organisms, 16 mg m^?2) were present. The observed distributional pattern is a classic serial discontinuity in response to hypolimnial stream regulation in a temperate latitude river.     

Impacts of Microcystis on algal biodiversity and use of new technology to remove Microcystis and dissolved nutrients

Cyanobacteria often dominate eutrophic lakes, outcompeting green algae that are required by fish and zooplankton. This study was undertaken to ascertain the impact of the cyanobacterium, Microcystis, on algal biodiversity. Under laboratory conditions, we found that the presence of Microcystis decreased phyla richness by 58%, phyla evenness by 47%, genera richness by 66% and genera evenness by 51%. Analysis by mixed anova s demonstrated a significant interaction between treatment and time and confirmed a significant reduction in richness and evenness of phyla and genera. We also conducted a phosphate restriction assay on the algae in Mason Lake (Irvine, CA, USA) and found that the threshold needed for algal growth there was 0.02 mg L^?1 PO₄. A pilot study was then conducted to test the effectiveness of the Blue Pro? water treatment facility in removal of this colonial organism from Mason Lake, in addition to removal of dissolved nutrients required for its growth. We measured a 97% reduction in Microcystis cells, a 72% reduction in chlorophyll‐a, and a 96% reduction in phosphate after just one 10 min cycle through the unit. Our study demonstrated that removal of Microcystis colonies may allow green algae to increase in numbers. This may improve algal biodiversity, which will benefit zooplankton and fishes.     

Evaluation of freshwater mussel relocation as a conservation and management strategy

The relocation of unionacean mussels is commonly used as a conservation and management tool in large rivers and streams. Relocation has been used to recolonize areas where mussel populations have been eliminated by prior pollution events, to remove mussels from construction zones and to re-establish populations of endangered species. More recently, relocation has been used to protect native freshwater mussels from colonization by the exotic zebra mussel Dreissena polymorpha. We conducted a literature review of mussel relocations and evaluated their relative success as a conservation and management strategy. We found that 43% of all relocations were conducted because of construction projects that were forced to comply with the Endangered Species Act 1973 and that only 16% were monitored for five or more consecutive years. Most (43%) relocation projects were conducted from July to September, presumably a period when reproductive stress is relatively low for most species and the metabolic rate is sufficient for reburrowing in the substrate. The mortality of relocated mussels was unreported in 27% of projects; reported mortality varied widely among projects and species and was difficult to assess. The mean mortality of relocated mussels was 49% based on an average recovery rate of 43%. There is little guidance on the methods for relocation or for monitoring the subsequent long-term status of relocated mussels. Based on this evaluation, research is needed to develop criteria for selecting a suitable relocation site and to establish appropriate methods and guidelines for conducting relocation projects.     

基于模型试验的河床砂砾石层基本特性研究

为了经济可靠地确定深厚覆盖层的基本特性参数,以大渡河双江口水电站坝基河床砂砾石层基本特性研究为工程背景,进行大尺寸模型试验,研究河床砂砾石层的旁压模量和动探击数随密度、级配以及上覆压力的变化规律。根据室内模型试验结果,结合现场旁压试验及钻孔试验成果,推断出坝址区河床砂砾石相关层位的密度,并依此进行砂砾石室内力学试验,获得设计所需力学参数。研究成果可为深厚覆盖层基本特性测试提供新的方法。     

SPATIAL AND TEMPORAL WATER QUALITY VARIABILITY IN AQUATIC HABITATS OF A CULTIVATED FLOODPLAIN

The floodplains of lowland rivers contain diverse aquatic habitats that provide valuable ecosystem services but are perturbed when intensively cultivated. Hydrologic, water chemistry and biological (fish) conditions in five aquatic habitats along the Coldwater River, Mississippi, were measured for more than 4 years: the river, two severed meanders that functioned as backwaters, a managed wetland and an ephemeral channel draining cultivated fields. Off‐channel habitats were connected to downstream regions 0.10% to 32% of the dry season and 24% to 67% of the wet season. The median temperatures for the five monitored sites ranged from 18°C to 23°C, the median total solids concentration for all sites was 135 mg L^?1, the median total phosphorus was 0.29 mg L^?1 and the median total nitrogen was 1.56 mg L^?1. Chemical and physical water quality displayed strong seasonal differences between the wet winter/spring and the dry summer/fall periods so that temporal variation consisted of gradual seasonal trends superimposed on strong diurnal variations. All off‐channel habitats exhibited periods of hypoxia and temperatures >30°C during the dry season. Between‐site gradients of water and habitat quality were strongly coupled to water depth and runoff loading. The rehabilitation of one backwater by increasing water depth and diverting agricultural runoff was associated with improved water quality and fish species richness relative to an adjacent untreated backwater. The diversion of polluted runoff and the use of water control structures to maintain greater water depth were observed to be effective management tools, but the former reduces the water supply to habitats that tend to dry up and the latter reduces connectivity. Published in 2011 by John Wiley & Sons, Ltd.     

簸箕李引黄灌区水沙分布及优化调度的经验

灌区利用水沙观测所取得的资料和试验数据，运用水沙运动力学理论，总结分析和揭示了灌区水沙分布的规律和特点。在此基础上，结合灌区的实际运行情况，围绕减少骨干渠道的淤积进行探讨、研究，进而，优化水沙调度方案。该方案实施后，骨干渠道减旅伴效果明显，取得了成功的经验。     

小湾水库大坝防渗面板及其裂缝的加固处理

小湾水库大坝防渗面板整体抗渗性能差,且存在多条裂缝,通过对面板钢丝网喷涂丙乳砂浆加固处理及其裂缝修补,大坝渗漏量明显减少,且左岸上灌浆廊道内及大坝下游坝面92～93 m高程下廊道入口处原有小股射流全部消失.     

基于BP神经网络-马尔科夫链模型的隧道围岩位移预测

在隧道工程施工中,围岩位移预测起着很重要的作用。将BP神经网络-马尔科夫链模型引入到隧道围岩位移预测中来,通过对训练样本的学习,利用BP神经网络实现了对位移时间序列的滚动预测,同时得到了实测值与预测值的相对误差;在此基础上利用马尔科夫链对相对误差进行修正,有效地提高了预测结果的精度。并将该模型应用于某公路隧道拱顶下沉位移时序预测中,结果表明该模型具有精度高、科学可靠的特点,为隧道围岩变形的预测提供了新的途径。