Spatial diversion and coordination of flood water for an urban flood control project in Suzhou, China

Suzhou City,located in the Yangtze River Delta in China,is prone to flooding due to a complex combination of natural factors,including its monsoon climate,low elevation,and tidally influenced position,as well as intensive human activities.The Large Encirclement Flood Control Project(LEFCP)was launched to cope with serious floods in the urban area.This project changed the spatiotemporal pattern of flood processes and caused spatial diversion of floods from the urban area to the outskirts of the city.Therefore,this study developed a distributed flood simulation model in order to understand this transition of flood processes.The results revealed that the LEFCP effectively protected the urban areas from floods,but the present scheduling schemes resulted in the spatial diversion of floods to the outskirts of the city.With rainstorm frequencies of 10.0%to 0.5%,the water level differences between two representative water level stations(Miduqiao(MDQ)and Fengqiao(FQ))located inside and outside the LEFCP area,ranged from 0.75 m to 0.24 m and from 1.80 m to 1.58 m,respectively.In addition,the flood safety margin at MDQ and the duration with the water level exceeding the warning water level at FQ ranged from 0.95 m to 0.43 m and from 4 h to 22 h,respectively.Rational scheduling schemes for the hydraulic facilities of the LEFCP in extreme precipitation cases were developed ac-cording to food simulations under seven scheduling scenarios.This helps to regulate the spatial flood diversion caused by the LEFCP during extreme precipitation.

Exploration of Sponge System Design in Wetland Parks Based on Rainwater and Flood Control: A Case Study of Southern Anhui Province

Based on the background that wetland resources in China are under threat and urgently need to be protected,a series of rainwater and flood problems caused by urban construction is analyzed comprehensively,and the design and planning methods of wetland parks in response to rainwater and flood disasters caused by floods and heavy rainfall are explored.Southern Anhui with complex and variable terrain and frequent rainfall and flood disasters is selected as the research area,with Xuanzhou District of Xuancheng City as the main research object.The relationship between municipal drainage of urban park and water conservancy drainage is investigated from different sample selection,design samples,and design flow rates.Based on literature review and model building methods,an urban storm flood model suitable for typical wetland parks in southern Anhui is constructed after processing the survey data using Arc GIS,SWMM(storm water management model).On this basis,a methodology and principles for designing a sponge system of wetland park based on rainwater and flood control are proposed,including technical measures such as rainwater collection,retention,and purification.This paper provides certain research results in design schemes,effect evaluations,ecological and social benefits,and useful suggestions and solutions for urban stormwater management and resilience development.

Decision Support System for Flood Control with Applications to Jiangxi Province

Affected by the climatic fluctuation and human activities, significant changes of the flood control situation are taking place in China. In the new century, the flood control systems have to face a series of challenges. In this paper, we design fa decision support system (DSS) for flood control based on its requirements. The DSS has been applied to decision-making for flood control in Jiangxi province, and play an important role in the flood control in the recent two years. Finally, we plot the further improvement on the DSS so that it will make more contribution in the flood control.

Methodological Proposition of an Integrated System for Urban Floods Control

In the State of Santa Catarina, Brazil, especially in the Itajai valley, there are records of accidents and disasters mainly associated to landslides and floods, which have caused significant damages and losses, including human lives. In order to make the coexistence with such natural disasters possible, most particularly with floods, a integration is required among the technical, political, environmental, and human knowledge. Measures that encompass integrated actions for the entire river basin, with the help from an updated technical cadastre and tools, such as the GIS, allow the development of planning tools that might effectively help the people to live with the water, or else to cope with floods in a more appropriate manner. This paper attempts to propose a methodology for urban flood control, based on the integration among the several public entities involved in the flood control, along with the CTM （Multipurpose Technical Cadastre） and GIS tool. In order to solve or minimize the problems, the model proposed here aims at promoting a balance between the agents involved, and enables to rank the degrees of importance assigned to the different needs, thus allowing to eliminate or to improve those areas and processes that are duplicated or superimposed.

ON THE HYDRAULIC FAILURE PROBABILITY OF FLOOD CONTROL DAMS

In flood control dams it is not only the failure to prevent flood larger than their design carrying capacity, but also the uncertainties of hydraulic factors that cause disasters. In general, the hydraulic risk is not considered in most of the hydrological analysis in floodproofing plan and design. In this paper, a method of evaluating the hydraulic risk is developed by employing risk theory, and the concept can easily be extended to other types of risk analysis. As a result, it is possible not to consider the hydraulic resks when the design hydrologic risk of flood control dam is lger. Otherwise, the hydraulic risks must be noticed. The research is very helpful for the development of the flood control theory used at present.

Application of Computer Simulation in the Reservoir Flood Control

[Objective] To discuss the application of simulation technique in preliminary solution of reservoir flood control of.[Method] Based on the study of river system simulation theory,the InfoWorks RS system was adopted to build a digital analog model for flood routing in certain river system and the flood discharge was analyzed with the check criterion.[Result] The flood information system based on InfoWorks RS simulated the inundation of downstream during flood discharge and drew mutation pictures to indicate how hydraulic parameters of maximum runoff at each control section,runoff of each control section and flow velocity varied with time,how hydraulic elements mutated with time as well as the most likely inundated area analysis of lower reservoir.[Conclusion] To provide references for reducing serious loss caused by flood and making out preliminary solution to flood control.

Hydrological adjustment and flooding control of wetlands in the Liaohe Delta

The function of estuary wetland on hydrological adjustment and flooding control is studied in this paper. It is estimated that the evapotranspiration in the reed field during growth season(June to October) is 722.9 mm, which is 37.5% higher than large water body(E 601∶525.9 mm). The water replacement rate in the reed field can reach 95% only when the rains continuously for 11 days and the precipitation reached 912 mm. For the water balance in the paddy field, the total water requirement ranges between 1920 and 1860 mm, among which, 31% is from precipitation, and the left is provided by reservoirs. The water usage efficiency is 0.35 at present productivity. Based on the landscape characteristics and functionalities on flooding control, 5 functional zones are designed for the Liaohe Delta: key protected area; underground storage area; flooding discharge area; flood diversion area in emergency; and flood control drainage area.

Potential control of climatic changes on flood events in the Yangtze Delta during1100-2002

Wide collection on the historic records of the climatic changes and flood events is performed in the Yangtze Delta. Man-Kendall (MK) method is applied to explore the changing trends of the time series of the flood discharge and the maximum high summer temperature. The research results indicate that the flood magnitudes increased during the transition from the medieval warm interval into the early Little Ice Age. Fluctuating climate changes of the Little Ice Age characterized by arid climate events followed by the humid and cold climate conditions give rise to the frequent flood hazards. Low-lying terrain made the study region prone to the flood hazards, storm tide and typhoon. MK analysis reveals that the jumping point of the time series of the flood discharge changes occurred in the mid-1960s, that of the maximum summer temperature changes in the mid-1990s, and the exact jump point in 1993. The flood discharge changes are on negative trend before the 1990s, they are on positive tendency after the 1990s; the maximum high summer temperature changes are on negative trend before the 1990s and on positive tendency after the 1990s. These results indicate that the trend of flood discharge matches that of the maximum high summer temperature in the Yangtze Delta. The occurrence probability of the maximum high summer temperature will be increasing under the climatic warming scenario and which will in turn increase the occurrence probability of the flood events. More active solar action epochs and the higher sea surface temperature index (SST index) of the south Pacific Ocean area lying between 4 o N-4 o S and 150 o W-90 o W correspond to increased annual precipitation, flood discharge and occurrence frequency of floods in the Yangtze Delta. This is partly because the intensified solar activities and the higher SST index give rise to accelerated hydrological circulation from ocean surface to the continent, resulting in increased precipitation on the continent.

Using modified Soil Conservation Service curve number method to simulate the role of forest in flood control in the upper reach of the Tingjiang River in China

To improve flood control efficiency and increase urban resilience to flooding,the impacts of forest type change on flood control in the upper reach of the Tingjiang River(URTR) were evaluated by a modified model based on the Soil Conservation Service curve number(SCS-CN) method. Parameters of the model were selected and determined according to the comprehensive analysis of model evaluation indexes. The first simulation of forest reconstruction scenario,namely a coniferous forest covering 59.35km^2 is replaced by a broad-leaved forest showed no significant impact on the flood reduction in the URTR. The second simulation was added with 61.75km^2 bamboo forest replaced by broad-leaved forest,the reduction of flood peak discharge and flood volume could be improved significantly. Specifically,flood peak discharge of 10-year return period event was reduced to 7-year event,and the reduction rate of small flood was 21%-28%. Moreover,the flood volume was reduced by 9%-14% and 18%-35% for moderate floods and small floods,respectively. The resultssuggest that the bamboo forest reconstruction is an effective control solution for small to moderate flood in the URTR,the effect of forest conversion on flood volume is increasingly reduced as the rainfall amount increases to more extreme magnitude. Using a hydrological model with scenarios analysis is an effective simulation approach in investigating the relationship between forest type change and flood control. This method would provide reliable support for flood control and disaster mitigation in mountainous cities.

Oil Production Optimization by Means of a Combined“Plugging,Profile Control,and Flooding”Treatment:Analysis of Results Obtained Using Computer Tomography and Nuclear Magnetic Resonance

Due to long-term water injection,often oilfields enter the so-called medium and high water cut stage,and it is difficult to achieve good oil recovery and water reduction through standard methods(single profile control and flooding measures).Therefore,in this study,a novel method based on“plugging,profile control,and flooding”being implemented at the same time is proposed.To assess the performances of this approach,physical simulations,computer tomography,and nuclear magnetic resonance are used.The results show that the combination of a gel plugging agent,a polymer microsphere flooding agent,and a high-efficiency oil displacement agent leads to better results in terms of oil recovery with respect to the situation in which these approaches are used separately(the oil recovery is increased by 15.37%).Computer tomography scan results show that with the combined approach,a larger sweep volume and higher oil washing efficiency are obtained.The remaining oil in the cluster form can be recovered in the middle and low permeability layer,increasing the proportion of the columnar and blind end states of the oil.The nuclear magnetic resonance test results show that the combined“plugging,profile control,and flooding”treatment can also be used to control more effectively the dominant channels of the high permeability layer and further expand the recovery degree of the remaining oil in the pores of different sizes in the middle and low permeability layers.However,for the low permeability layer(permeability difference of 20),the benefits in terms of oil recovery are limited.

Urban flood control strategy based on new relationship of human and flood

China is one of the countries with the most serious flooding disasters.In China,above 70% of big cities,50% of population and 75% of industrial and agricultural output value are distributed in eastern coastal areas with serious flooding.Therefore,enhancement of theoretical study and experience summarization of urban flood control is of great theoretical and practical significance.As economy is developing rapidly,urban scale is expanding fast,and urban flood control stand is promoted.Urban flood control calls for new concept and methods.This paper makes a systematic summarization of concept evolution and advanced methods concerning urban flood control at home and abroad.The concept of urban flood control has transformed from simple flood control and drainage to coexistence with and use of flood.Flood control measures have transferred form emphasis upon engineering ones to priority to both engineering and non-engineering ones,with special attention to ecological flood control,such as making full use of ecological revetment,ecological realignment of a river,multi-objective management of urban flood detention region,turning flood into resources and utilization of wetlands.

New Challenges and Opportunities for Flood Control in the Huai River: Addressing a Changing River-Lake Relationship

This paper addresses the change of the river-lake relationship in the Huai River and its causes due to environmental change and human activities. A preliminary analysis is made from three aspects: (1) the natural geographical change particularly captured by the Yellow River, (2) water conservancy project construction, and (3) socioeconomic development in the Huai River Basin. Key problems of changes in this river-lake relationship and the Huai River flood control are tackled, involving flood control and disaster alleviation ability of the Basin, engineering and non-engineering measurements applied to flood control and disaster mitigation, and water governance for adaptive management. Research shows that the Huai River is a rather complex one due to its complex geography with a hybrid wet and dry climate zoon, and higher population density. With the alternation of the river-lake relationship and socioeconomic development in the region, new problems keep arising, imposing new requirements on its sustainable water management. Thus, understanding the Huai River is a long and gradually improving process. Its future planning should keep absorbing new achievements of science and technology development, employing new technologies and methods, and gradually deepening our understanding of its fundamental principles. Water governance and adaptive water management will be new challenges and opportunities for the Basin in its river system change and flood control.

The Effect of Geologic Structures on the Control of Floods in the Middle Yangtze River Valley

This paper discusses the role of geologic structures in the occurrence of floods and how to prevent flood in the middle reaches of the Yangtze River, and gives the author's suggestion that the Luoshan Qiakou be expanded and the land reclaimed from Dongting Lake be returned to the lake in compliance with the law of geology.

FLOOD CONTROL PROGRAMME IN BANGLADESH

Bangladesh locates in lower reach of Ganges-Brahmaputra-Meghma, Bengal delta. Bangladesh is a land of rivers and heavy monsoon rains. Every year during monsoon period (May-September)the country floods of verying magnitude, it causes damages to crops, properties, infrastructures, etc. and ultimately affects the economy development of the country. Banglandesh flood has some features given below: 1. The excessive rainfall over the vast catchment area of the river is the main cause of flood in Bangladesh, but 90% of the flood carried by rivers come from outside the country, i.e. regional countries, India, Nepal,

The flood control and regulation of Three Gorges Project

The important role of Three Gorges Project (TGP) in the flood management of the Yangtze River Basin is summarized.The Optimal Regulation Schemes of the Three Gorge Reservoir is briefly described.The flood regulation effect of TGP is analyzed.Typical issues related to reservoir operation for flood regulation are discussed and suggestions are put forward for the future work.

Improvement Strategies of Flood Control Landscape in Suburban Villages and Towns from the Perspective of Aquaphilia and Livability

In the context of urban and rural integrated development, many suburban villages and towns are still threatened by both urbanization and natural disasters. In order to explore the improvement strategies of flood control landscape integrating water ecology, water safety, water culture and water landscape, the Luozhou Ancient Town by the Wulong River in Fuzhou City was taken as an example, and the concept of pluralistic symbiosis from the perspective of aquaphilia and livability was proposed through field investigation, data monitoring, site analysis and planning, that is, while retaining the positive attributes of “boundary”, its negative limitation of “pluralistic” space is broken, so as to establish a pluralistic and symbiotic environment with aquaphilia and livability. It can not only effectively alleviate the contradictions between urban and rural areas, between water and land, and between old and new cultures, but also activate the vitality of suburban villages and towns, providing a new idea for the improvement of flood control landscape.

Flood risk assessment of check dams in the Wangmaogou watershed on the Loess Plateau of China

Check dams have been widely used in China’s Loess Plateau region due to their effectiveness in erosion and flood control.However,the safety and stability of the check dam decrease with the operation process,which increases the probability of dam failure during flood events and threatens local residents’ life and property.Thus,this study simulated flood process of the check dam failure in the Wangmaogou watershed in Yulin City,Shaanxi Province,China,calculated different types of inundation losses based on the flood inundation area within the watershed,and determined the number of key flood protection check dams by classifying the flood risk levels of the check dams.The results showed that 5 dams in the watershed were subject to overtopping during different rainfall return periods,which was related to their flood discharge capacity.Dam failure flood process showed a rapid growth trend followed by slow decrease,and the time of flood peak advanced with increase in the return period.After harmonization of evaluation scales,the magnitude of flood inundation losses can be ranked as:economic losses(212.409 million yuan) > life losses(10.368 million yuan) > ecological losses(6.433 million yuan).The risk value for both individual dams and the whole dam system decreases as the return period increases.The number of key flood protection check dams in the Wangmaogou watershed was 2,3,3,3,4,and 5 for floods with return periods of 10,20,30,50,100,and 200 years,respectively.The results provided a theoretical basis for the safe operation and risk evaluation of check dams in the Loess Plateau Hills watershed.

THE WARNING OF THE '98 YANGTZE DELUGE & OUR FLOOD CONTROL STRATEGY

Based on a panoramic analysis of the serious Yangtze deluge in 1998 and its hydrological traits, the authors elucidate the formative factors of the deluge and review existing flood-control policies in retrospect. In addition, some countermeas-ures are suggested for coping with similar calamities in the near future.

REMOTE-SENSING TECHNOLOGY IN FLOOD CONTROL IN CHINA

This article expounds the vital role undertaken by telemetry in monitoring and assessment in flood control in China. By analyzing the data from their surveys, the authors give an all-round exposition of problems in the country’s drive for disaster reduction and propose countermeasures in the fight against the possible flood problems in the future.