Improved PSO algorithm based on chaos theory and its application to design flood hydrograph

The deficiencies of basic particle swarm optimization （bPSO） are its ubiquitous prematurity and its inability to seek the global optimal solution when optimizing complex high-dimensional functions. To overcome such deficiencies, the chaos-PSO （COSPSO） algorithm was established by introducing the chaos optimization mechanism and a global particle stagnation-disturbance strategy into bPSO. In the improved algorithm, chaotic movement was adopted for the particles＇ initial movement trajectories to replace the former stochastic movement, and the chaos factor was used to guide the particles＇ path. When the global particles were stagnant, the disturbance strategy was used to keep the particles in motion. Five benchmark optimizations were introduced to test COSPSO, and they proved that COSPSO can remarkably improve efficiency in optimizing complex functions. Finally, a case study of COSPSO in calculating design flood hydrographs demonstrated the applicability of the improved algorithm.

Impacts of water surface area of watershed on design flood

In order to analyze the impact of the water surface area of a watershed on the design flood, the watershed was classified into a land watershed and a water surface watershed for flood flow calculation at the same time interval. Then, the design flood of the whole watershed was obtained by adding the two flood flows together. Using this method, we calculated design floods with different water surface areas of three reservoirs and analyzed the impact of water surface area on the flood volume and peak flow. The results indicate that larger water surface areas lead to greater impacts on the flood volume and peak flow. For the same watershed area, the impact of water surface area on the flood volume and peak flow is positively proportional to the flood frequency, i.e., the higher the frequency, the greater the impact becomes.

Regional Design Storm and Flood Modelling—Risk Implications in Ungauged Catchments

Most planned developments in a catchment for control of excess water using a culvert, bridge or dam spillway are located at a site in a stream where there are no discharge measurements. Even though, for gauged catchments a number of established flood frequency models and rainfall-runoff models do exist, for ungauged catchments mostly regional flood frequency and event-based rainfall-runoff models are used, which depend on regional parameters. In this paper, a regional approach for design floods is presented and risk implication for design of drainage structures assessed. A case study in light of the above has been considered at four ungauged sites in the Limpopo Drainage Basin in north-eastern Botswana.

Design flood of ungauged basins based on DEM

In this paper,the northern mountainous area of Fuzhou City which is an ungauged basin has been taken for example to discuss the method of design flood calculation by means of combining the DEM(digital elevation model) and the Xin'anjiang Model(three components).The problem of estimating the parameters of the runoff model has been solved by using the parameters of the reference station.In the conflux calculation,the isochrones are obtained by DEM which helps to avoid the cumbersome work of drawing them on the map.With the establishment of the digital elevation model throughout the country,it is practically significant to use it in the hydrological estimation.

Research on Flood Control Design Based on Joint Distribution of Flood Levels and Flood Peak Discharges

The return level of the joint distribution of flood levels and flood peak discharges was analyzed by Archimedean Gumbel-Hougaard copula and Kendall distribution functions.Using the annual maximum level(H)and discharge(Q)of flood peak at Boluo Hydrologic Station in the Dongjiang River in last 56 years,the"OR"return period,"AND"return period and Kendall return period of their joint distribution and the most likely design flood value were calculated.The main conclusions of this study can be summarized as follows:the Kendall return period can more accurately reflect the risk rate of the combination of flood elements,relative to"OR"return period and"AND"return period.The design value of univariate flood element based on the current specification can meet the design standard.While the design value calculated according to"OR"return period was on the high side,and the design value calculated by the"AND"return period was on low side.Based on the principle of maximum probability,the calculated design value of Kendall return period under the different combinations of flood peak discharge and water level can provide new options for flood control project safety and risk management.

INTEGRATED DESIGN FOR FLOOD RISK AND SPATIAL QUALITY-EXAMPLES FROM THE DUTCH DELTA PROGRAMME

INTRODUCTION The Netherlands faces a significant flood risk task. In order to remain a safe place to live the Netherlands has to upgrade its extensive flood risk protection system. This results in an elevation and reinforcement task for many of the Netherlands water barriers. When those barriers are positioned in an open landscape, the technical rein-forcement is often easy to embed specially. However, many barriers have been built over the years making the reinforcement into a challenging spatial assignment. This article shows different case study examples of a research by design study (performed in the broader context of the Dutch Delta programme) that explores integral design solutions for flood risk and spatial (re)development. The Houston Galveston Bay case study demonstrates the international applicability of the research by design method.

Steam Flooding after Steam Soak in Heavy Oil Reservoirs through Extended-reach Horizontal Wells

This paper presents a new development scheme of simultaneous injection and production in a single horizontal well drilled for developing small block reservoirs or offshore reservoirs. It is possible to set special packers within the long completion horizontal interval to establish an injection zone and a production zone. This method can also be used in steam flooding after steam soak through a horizontal well. Simulation results showed that it was desirable to start steam flooding after six steam soaking cycles and at this time the oil/steam ratio was 0.25 and oil recovery efficiency was 23.48%. Steam flooding performance was affected by separation interval and steam injection rate. Reservoir numerical simulation indicated that maximum oil recovery would be achieved at a separation section of 40-50 m at steam injection rate of 100-180 t/d; and the larger the steam injection rate, the greater the water cut and pressure difference between injection zone and production zone. A steam injection rate of 120 t/d was suitable for steam flooding under practical injection-production conditions. All the results could be useful for the guidance of steam flooding projects.

Application of Flood Routing Model for Flood Mitigation in Orashi River, South-East Nigeria

The study focused on the application of Flood Routing Models for Flood Mitigation in Orashi River, South-East Nigeria. Flood data were collected for the study area and subjected to statistical analysis. Three flood Routingmodels were comparatively applied including Muskingum model, Level Pool model and Modified Pul’s model. Assumed routing period of 2.3 hours which helped to check excessive flood at the downstream section of the river was used. Also a dimensionless weighting factor of 0.15 was also adopted. Muskingum model and Level Pool model which represent linear relationship between measured outflow and predicted outflow for specified inflow and time change of one hour gave high and positive values of coefficients of correlations of 0.9769 and 0.9732 respectively. The Modified Pul’s model which also represents a linear relationship between measured outflow and predicted outflow for specified inflow and a time change for one hour showed the highest coefficient of correlation of 0.9984 and lowest standard error of 0.1749. Though, flood models of the Muskingum method and Level Pool method exhibited good correlation, their prediction differed significantly with the corresponding models of original data sets because of high standard error and thus not adequate for field application in similar rivers. A design application was carried out using the Modified Pul’s model. The values obtained for routed storage capacity was 348 m3 while the designed capacity was 354 m3. It is recommended that dredging of the river is carried out to achieve the designed capacity. This would eliminate the risk of flooding. The results of the study will serve useful purposes in predicting flood events and design of flood control works in similar basins.

Using Design Thinking and Facebook to Accompany Women in Solving Water Problems in Morocco

Environmental issues are complex and malicious problems involving many characteristics, variables, increasing their level of uncertainty. How should victims of these problems be accompanied when trying to solve such complex environmental disasters？ A broad understanding of these problems and a feeling of self-efficacy must be present in problem solvers in order for them to persevere up to the formulation of effective solutions. Two new trends in problem solving inspired the development of an approach to accompany citizens dealing with environmental problems： design thinking and the use of ICT in problem solving. Design thinking, a creative solving approach created by IDEO, is a collaborative way to work during which intuition, abductive thinking, quick prototyping and the consumers＇ needs are put first. As for ICT, they can now be used to store, share, develop and criticize information and solutions （Facebook, Padlet... ）. Design thinking and Facebook were drawn on to accompany 10 poorly educated Moroccan women in solving a problem arising from flooding of the Ourika river. The women were taught to use electronic tablets and Facebook. During workshops and through Facebook, women were invited to share their experiences with floods and to find solutions to the poor quality of their drinking water, after floods. Design thinking allowed participants to explore many dimensions of the chosen problem and to prototype a certain number of solutions to purify their water. Facebook was profitable to better define the problem and as a communication and brainstorming tool （before and during the water filtration prototype trials）. Design thinking and Facebook turned out to be effective tools to pose the water problem more widely, to find solutions adapted to the participants＇ living conditions and to improve their self-efficacy in problem solving as well as their collaboration.

Design of a Simulator for Enhanced Oil Recovery Process Using a Nigerian Reservoir as a Case Study

This study involves the applications of different numerical techniques in a more general way to the design of a simulator for an enhanced oil recovery process with surfactant assisted water flooding. The data from a hypothetical oil well and a Nigerian oil well were used for the validation of the simulator. The process is represented by a system of nonlinear partial differential equations: the continuity equation for the transport of the components and Darcy’s equation for the phase flow. The orthogonal collocation, finite difference and coherence theory techniques were used in solving the equations that characterized the multidimensional, multiphase and multicomponent flow problem. Matlab computer programs were used for the numerical solution of the model equ- ations. The predicted simulator, obtained from the resulting numerical exercise confers uncondi- tional stability and more insight into the physical reservoir description. The results of the ortho- gonal collocation solution were compared with those of finite difference and coherence solutions. The results indicate that the concentration of surfactants for orthogonal collocation show more features than the predictions of the coherence solution and the finite difference, offering more opportunities for further understanding of the physical nature of the complex problem. We have found out that the partition of the three components between the two-phases determines other physical property data and hence the oil recovery. The oil recovery for the Nigerian oil reservoir is higher than the recovery predicted for the hypothetical crude. The displacement mechanism for the multicomponent and multiphase system is stable in the Nigerian oil reservoir due to the mod- erate value of the oil/water viscosity instead of the hypothetical reservoir with high value of oil/water ratio.

面向新时期新需求的三峡水库运行方案研究

本文回顾三峡水库设计洪水、特征水位、运行方案变化调整过程,综述三峡水库运行调度关键技术研究进展和分析来水来沙变化情况。分别采用最可能洪水地区组成法和非一致性洪水频率分析两种途径,推求考虑上游水库群调蓄影响的三峡水库运行期设计洪水及特征水位。结果表明:近10年三峡入库泥沙量比初设成果减少了84.4%,宜昌站水文情势IHA-RVA综合指标为74%、发生了重度改变,三峡水库运行期1000年一遇7~15 d洪量减少了约81.5亿~142.8亿m^(3),初设确定汛限水位的主要制约因素(防洪、泥沙)发生了很大的变化。原单站设计洪水及确定的三峡水库175-155-145 m运行方案,已无法满足新时期水资源高效利用和生态环境保护的新需求。建议把三峡水库运行方案调整为175-160-155 m,主汛期水位在155~160 m区间动态控制运行,长江中下游梅雨结束后应考虑提前蓄水,8月底蓄至163 m左右,9月底蓄至165 m,10月底蓄满。该方案在保证大坝和下游防洪安全的前提下,汛期减少弃水并增加枯水期补水量,预计可增发10%左右的发电量;抬高运行水位也有利于库区航运和减少消落带;9月份尽量不蓄水或少蓄水,可减少蓄水期对下游河道及两湖生态环境的不利影响,具有巨大的经济、社会和生态环境等综合利用效益。当预测预报长江流域可能发生流域性大洪水时,尽快将库水位消落至汛限水位145 m,确保大坝和下游防洪安全。

基于大语言模型辅助的防洪调度规则标签设计方法

防洪调度规则的信息抽取对于防洪调度自动化具有重要意义,而标签体系设计在信息抽取任务中至关重要。一般的设计方式经常由于理解偏差和疏漏,导致设计出来的标签体系存在过度概括、不全面和不易区分等问题,这些问题被称为标签体系的非完美性。针对这一问题,本研究重点面向防洪调度文本中的规则抽取,提出了一种创新性的非完美标签优化方法,旨在改进文本信息抽取的标签设计方法。方法利用大语言模型进行辅助,通过标签细化、标签生成和标签更名等措施,来提高标签的准确性和表达能力。此外,本文还提出了一种针对数据集标签较多的实体关系三元组分组抽取方法。通过对实体关系三元组进行分组,并按照分组训练模型与识别结果,有效改善了数据集标签较多情况下模型的信息抽取效果。最终,研究利用Neo4j形成了可视化的防洪调度知识图谱。本文研究成果为后续的防洪调度工作以及相关的知识抽取工作提供了基础资源,对防洪调度领域的知识抽取进行了探索。

基于HEC-RAS的陇南山地山洪灾害风险图优化研究

短历时山洪是威胁陇南山地交通和村镇安全的重要灾害之一。为提高该地区防灾减灾能力,通过不同雨强计算出洪水淹没损失程度,利用洪水风险区划图指导当地群众预防山洪灾害具有重要的科学意义。基于HEC-RAS水文分析方法,结合GIS软件模拟了流域洪水淹没过程,以陇南山地蒲家沟为研究对象,在5、10、50、100 a一遇设计雨量条件下,综合考虑坡度、土地类型、损失率、水位和流速等多种因素,对传统洪水风险区划图进行优化。结果表明,相比传统方法绘制的风险区划图,优序图法优化后的风险区划图更加重视承灾体的受影响程度,且解决了传统风险区划图中小区域风险等级跨度大,风险等级难以定级的缺点。优化后的风险区划图,上中游无人区风险等级降低,下游人类活动区域风险等级更加明确。以马泉村王家咀为例,在50 a一遇的设计雨量下,传统方法绘制的风险区划图其划分结果涵盖5个风险等级,各区域面积差距不显著,难以确定最终的风险等级。而优序图法优化后的风险区划图划分结果更加集中,王家咀高风险区域面积不足中风险的4%,王家咀风险区域可以明确地定位到中风险。文中优序图法优化后的风险区划图在实用性和适应性上更具优势,可以为小流域山洪预警预报和防灾减灾工作提供帮助。

基于DEM的陕西省中小流域设计洪水软件开发

为规范和高效简捷地计算暴雨推求设计洪水,避免烦琐的查表和手工计算,针对陕西省中小流域设计洪水软件的空白,研发了基于DEM(Digital Elevation Model)的暴雨推求设计洪水的软件。该软件利用不同历时的点暴雨均值和变差系数等值线图生成DEM数据源,点选可自动获取工程所在位置的所有参数。采用推导的数值解法对产流过程和汇流过程进行程序开发,实现了陕西省无资料地区中小流域设计洪水计算的可视化高效计算和快捷规范的输出,显著提高了计算精度和工作效率。该软件算法和开发方法可推广应用于全国其他省市中小流域无资料地区设计洪水的计算。

城市蓄滞洪区生态水景公园概念规划及景观节点详细设计:以宋庄蓄洪生态水景公园为例

宋庄蓄滞洪区是北京城市副中心防洪格局通州堰中的重要组成部分,其防洪功能至关重要。为了使蓄滞洪区既满足汛期防洪调蓄的作用,降低洪水对周边地区的影响,保障市民的生命财产安全,又满足市民非汛期生态休闲目的,以宋庄蓄洪生态水景公园为例,结合现状条件和洪水的启示,打破原有水绿界限,提出全新的设计理念,重视前期规划设计,通过融合多种功能、塑造立体空间、打造技术亮点等方法与水系串联、土方平衡、湿地净化、绿化种植等措施相结合,构建绿色、生态、健康的开放式生态水景公园——宋庄沁园,实现宋庄蓄洪区的综合利用。以生态水景的形态与东郊森林公园、温榆河河堤自然串联为一个整体,保障副中心的防洪安全,提高蓄洪调度能力,有效降低洪水风险,提升周边生态环境,满足市民观景、休闲、健身等活动需求,充分展示水生态、水文化、水技术等科普知识,成为副中心“通州堰”生态水景观体系的点睛之笔。

岩溶山区小流域水库工程设计洪水计算——以WL水库工程为例

为科学合理确定岩溶山区小流域水库工程设计洪水,以WL水库为研究对象,考虑坝址以上伏流区、明流区分布,按全面积法、分块叠加法分别计算设计洪水,经综合比较确定坝址推荐设计洪水过程。结果表明,分块叠加法计算的设计洪水成果与坝址下游历史洪水调查成果较接近,能反映伏流区对坝址洪水调节的实际情况,并与区域已有洪水成果协调,为该工程坝址推荐设计洪水成果。本研究成果对开展区域岩溶山区水库设计洪水计算工作有一定的借鉴意义。

基于经验模态分解重构方法的北江飞来峡洪水频率分析

在历史洪水考证(1764—)和实测洪水(1953—2024年)的基础上,应用时序图、滑动均值、M-K方法、Hurst指数等对北江飞来峡站洪水的一致性进行了检验;根据P-Ⅲ频率分析方法,采用历史考证洪水对洪水系列重新排序进行洪水频率分析,基于经验模态(Empirical Mode Decomposition,EMD)分解与合成的频率计算方法对洪水频率进行了分析计算。结果表明:北江极端洪水自1990年代中期表现出趋多趋频趋强的特点,经检验发生了显著变异;采用传统的水文频率计算方法得到的各频率洪水设计值比原设计值增大500~600 m^(3)/s;采用基于EMD分解与合成的频率计算方法得到2020水平年的各频率设计值增大3500 m^(3)/s以上,2030水平年的各频率设计值增大3800 m^(3)/s以上。基于EMD分解重构的洪水频率计算方法能够及时对变化环境做出响应,具有一定的推广应用价值。北江飞来峡站的水文频率计算结果发生了较大的改变,宜尽快重新核定。

万泉河流域设计洪水分析

编制河流治理开发方案,需要合理可靠的设计洪水成果。以万泉河设计洪水计算为例,分析了历史洪水重现期,进行了水文站洪水系列一致性处理,建立了干流水文站之间的洪峰、洪量相关关系,插补延长了洪水系列,确定了水文站设计洪水成果。根据流域具有调蓄作用水库的兴建时间,计算不同分区的区间设计洪水。分析流域洪水遭遇情况,采用典型年法和同频率法分析设计洪水地区组成,采用分区时段洪量控制选取相对不利的典型年实测洪水过程为典型,推求防洪控制断面设计洪水过程线。

梯级水库下游最不利洪水地区组成法

梯级水库运行调度显著改变了下游洪水的时程分配,而现有洪水地区组成法没有考虑对工程设计和防洪调度最不利或最恶劣的情景。本文基于灾害风险理论,根据未控区间洪量及地区组成概率,提出一种最不利洪水地区组成法。雅砻江梯级水库实例分析表明:最不利地区组成法分配给下游未控区间流域的洪量总是大于同频率组成法和最可能组成法;最不利组成法推求的雅砻江出口断面1 000年一遇设计洪峰、3 d和7 d洪量分别为16 700 m^(3)/s、41.6亿和85.1亿m^(3),均大于其他洪水地区组成法估计值。理论推导和统计试验表明最不利地区组成法可合理分配洪量并兼顾下游防洪风险,具有深入研究和应用的价值。

王家会集运站段三川河河道洪水分析计算

根据王家会集运站与三川河的位置关系,基于后大成水文站洪峰流量的计算成果,利用水文比拟法推算王家会集运站站址处设计断面洪水,采用两种方法考虑水库对设计断面洪水的影响,最终分析确定集运站站址处设计洪峰流量。