Flood Retarding Research Articles

Interaction of planning and hydraulic investigation of flood retarding basin Weilers/Bracht

Interaction of planning and hydraulic investigation of flood retarding basin Weilers/Bracht

Hydrodynamics and water quality of the Hongze Lake in response to human activities.

The hydrodynamics and water quality of a lake in response to human activities is an important yet poorly understood issue. In this study, the responses of flow field, water level, and water quality of the Hongze Lake to changes in land use, project operation, and pollution accident were investigated using the 2D hydrodynamic model, water quality model, and hydrological model. The results show that project operations have more significant effects on the hydrodynamics and water quality of the Hongze Lake than changes in land use. In addition, the construction and operation of various water conservancy projects could increase pollutant diffusion and water exchange, thus contributing to improve the water quality of the Hongze Lake, but there is a need to solve the problem of rising water level in the Lihe depression lake area. The increase of urban and farmland area can significantly affect the flow of the Hongze Lake that could increase the flood risk. The simulations of the loosely coupled model imply that the coupling among the hydrodynamic model, water quality model, and SWAT model for the lake basin is feasible. Furthermore, a model based on the space grid was proposed in the study and combined with the verified loosely coupled model to assess the flood risk in the Hongze Lake, which could improve water resources and flood retarding basin operations.

Influence of the Flood on the Flow Characteristics in Different Flood and Tide Combination Scenarios: A Case Study in Puyang River a Tributary of Qiantang River

Huang, J. and Zhang, H., 2019. Influence of the flood on the flow characteristics in different flood and tide combination scenarios: A case study in Puyang River a tributary of Qiantang River. In: Guido-Aldana, P.A. and Mulahasan, S. (eds.), Advances in Water Resources and Exploration. Journal of Coastal Research, Special Issue No. 93, pp. 178–184. Coconut Creek (Florida), ISSN 0749-0208.Based on the background of Puyang Jiang River, a 2D hydrodynamic model was built to explore the distribution characteristics of tidal range in the downstream section of Puyang River under different flood tide combinations between Puyang River and Qiantang River. The influence of different frequency floods and flood discharges of Puyang River on the flood level of Puyang River was analysed. The results show that the tidal range at each point of the exit section decreases with the increase of floods in Puyang River. Under the same flood conditions of Puyang River, the tidal range at each point of the river increases with the increase of the Qiantang River rushing tide; under the same characteristic tidal conditions, the tidal gradient along the water flow direction of the Sanjiangkou-Xizhuang section increases with the increase of floods in the Puyang River. When Puyang Jiang River suffered flooding from once ten years to twenty years and then to fifty years, the mean value of water level reduction of east and west river is from 0.66 cm to 0.72 cm and then to 0.63 cm, namely, the sensitivity of the discharge of Gaohu flood retarding basin to the water level of east and west river of Puyang Jiang River is first strengthened and then weakened. The research results provide a guidance for flood regulation of Puyang River and optimization of operation in Gaohu flood detention area.

Optimal Operation Research of Flood Retarding in Plain River Network Region

The operation of flood retarding areas does not attract much attention, although they are important components of flood control systems. Poor operation of such areas restricts not only the socio-economic development of the flood retarding area, but also limits scientific flood control options. As the second-largest flood retarding area in China, with more than 2000 km2 and 300 polders, the Hongze Lake vicinity was taken as a case study of graded flood retarding. A one and two-dimensional coupled hydrodynamic model was established to simulate flood routing in the Hongze Lake area. Fifteen different schemes involving different flood magnitudes and flood retarding operations were simulated. The results show that (1) having a flood retarding area is essential; and (2) the “graded flood retarding” scheme is superior to “no grading flood retarding” scheme; and (3) a “two-grade flood retarding” scheme is recommended.

Analytical solution of dam-break flood wave propagation in a dry sloped channel with an irregular-shaped cross-section

Cross-sectional channel shape is a primary factor influencing dam-break floods. However, it is difficult to analytically understand the impact of the cross-sectional shape on flood wave propagation because most of the existing analytical solutions are only applicable to channels with specific cross-sections (e.g., rectangular, parabolic and triangular cross-sections). Here, a polyline cross-section representing a realistic scenario and derivation method were suggested for analyzing dam-break floods down a dry sloping channel. With the proposed model, the flow depth, average velocity and discharge profiles after an instantaneous dam break can be presented as three dimensionless curves. The effect of bed slope on the dam-break wave was evaluated. Both the flood acceleration on a downward-sloping channel and the flood retardation on an upward-sloping channel are illustrated clearly with the analytical solution in an example application. The effect of the bed slope on wave propagation becomes more prominent over time. The flow depth, average velocity and discharge at the dam site remain constant for a horizontal bed and vary with time for a sloping bed. Three-dimensional numerical simulations of the examples were performed using a large eddy simulation (LES) model along with the Volume of Fluid (VOF) approach for surface tracking. A comparison between the analytical and numerical solutions shows that the analytical model can provide the main features of dam-break floods and therefore can be used for the rapid prediction of dam-break flows. The model limitations are also presented.

Modifying and Validating the SWAT Model to Determine Landuse Effects on Watershed Water Quality: Using a Dual Level of Model Performance Based on Subbasin Size

The North Bosque River (NBR) was included in the Clean Water Act § 303(d) impaired list. The Texas Institute for Applied Environmental Research used the Soil Water Assessment Tool (SWAT) to develop a phosphorus (P) Total Maximum Daily Load. SWAT was modified to dynamically change manure application rates based on simulated annual soil P, change areas receiving manure, alter manure quantities each year, apply liquid and solid manure pools separately, move manure between subbasins, improve landscape P processes, model contributions of dairy lagoon discharges and improve in-stream water quality kinetics. Data was refined to increase spatial resolution of subbasins and include Public Law (PL)-566 flood retardation reservoirs. A dual level of model performance was established: one level for large drainage areas and a reduced performance level for all other sites. Main stem sites were to have streamflow, sediment, total nutrients achieve the “good” rating from Moriasi et al. (2007). For secondary sites and constituent parts of total nutrients besides PO4 the “satisfactory” rating was acceptable model performance. This dual level of model performance was developed in recognition of uncertainties in model input and measured data that resulted in better model performance for larger drainage areas as compared to smaller drainage areas, and for total nutrients as opposed to their constituent parts. The refined SWAT model was successfully validated for both historical long-term (30-year) base, surface and total streamflow data and monthly streamflow and nutrient loads , as well as average daily load and concentration using water quality and streamflow data.

Real-time flood forecasting of Huai River with flood diversion and retarding areas

A combination of the rainfall-runoff module of the Xin'anjiang model, the Muskingum routing method, the water stage simulating hydrologic method, the diffusion wave nonlinear water stage method, and the real-time error correction method is applied to the real-time flood forecasting and regulation of the Huai River with flood diversion and retarding areas. The Xin'anjiang model is used to forecast the flood discharge hydrograph of the upstream and tributary. The flood routing of the main channel and flood diversion areas is based on the Muskingum method. The water stage of the downstream boundary condition is calculated with the water stage simulating hydrologic method and the water stages of each cross section are calculated from downstream to upstream with the diffusion wave nonlinear water stage method. The input flood discharge hydrograph from the main channel to the flood diversion area is estimated with the fixed split ratio of the main channel discharge. The flood flow inside the flood retarding area is calculated as a reservoir with the water balance method. The faded-memory forgetting factor least square of error series is used as the real-time error correction method for forecasting discharge and water stage. As an example, the combined models were applied to flood forecasting and regulation of the upper reaches of the Huai River above Lutaizi during the 2007 flood season. The forecast achieves a high accuracy and the results show that the combined models provide a scientific way of flood forecasting and regulation for a complex watershed with flood diversion and retarding areas.

A Comparative Study on Flood Management in China and Japan

Attempts at flood management during the 20th century resulted in more flood disasters. To gain a better understanding of what went wrong, it is necessary to examine historical evidence, seek ancient wisdom and compare practices of flood management in different countries. This study examines flood management concepts and practices in China and Japan during different periods of time in history and the differences in the two countries’ current management of flood retarding basins. It reveals that during the Western Han Dynasty (206 BC–24 AD), China proposed to redirect a river course to gain sufficient flood retarding capacity, and this same concept was realized, either coincidentally or intentionally, during the Edo period of Japan (1603–1868). In modern times, however, the management of flood retarding basins differs fundamentally between China and Japan. In addition, this study investigates the differences in emergency evacuation practices between China and Japan. This is the first study to highlight the link between a Chinese concept and a Japanese practice that are separated by more than 1000 years.

Upper washita river experimental watersheds: reservoir, groundwater, and stream flow data.

Surface and groundwater quantity and quality data are essential in many hydrologic applications and to the development of hydrologic and water quality simulation models. We describe the hydrologic data available in the Little Washita River Experimental Watershed (LWREW) of the Southern Great Plains Research Watershed (SGPRW) and Fort Cobb Reservoir Experimental Watershed (FCREW), both located in southwest Oklahoma. Specifically, we describe the flood retarding structures and corresponding stage, discharge, seepage, and consumptive use data (), stream gauges, and groundwater wells and their corresponding stream flow (; LWREW ARS 522-526 stream gauges) and groundwater level data (SGPRW groundwater levels data; LWREW groundwater data; ; ), respectively. Data collection is a collaborative effort between federal and state agencies. Stage, discharge, seepage, and consumptive use data for the Fort Cobb Reservoir are available from the Bureau of Reclamation and cover a period of 1959 to present. There are 15 stream gauges in the LWREW and six in the FCREW with varying data records. There were 479 observation wells with data in the SGPRW and 80 in the LWREW, with the latest records collected in 1992. In addition, groundwater level data are available from five real-time monitoring wells and 34 historical wells within the FCREW. These data sets have been used for several research applications. Plans for detailed groundwater data collection are underway to calibrate and validate the linked Soil and Water Assessment Tool (SWAT)-MODFLOW model. Also, plans are underway to conduct reservoir bathymetric surveys to determine the current reservoir capacity as affected by land use/land cover and overland and stream channel soil erosion.

Study of Urban Flood Control Planning in Taiyuan

Considering topography, climate, river system, and existing problems in Taiyuan, the urban flood control planning in Taiyuan boils down to the following points: determine the flood control standard according to the size of city; study the flood alleviating measures in the upstream area; provide adequate water and soil conservation measures in the mountainous areas reduce flash floods; divert flood from mountainous areas to the downstream area instead of to the urban; improve the river channels in the urban area; provide flood detention and retarding area in the downstream area; study non-engineering flood control measures.

Development and application of an atmospheric-hydrologic-hydraulic flood forecasting model driven by TIGGE ensemble forecasts

A coupled atmospheric-hydrologic-hydraulic ensemble flood forecasting model, driven by The Observing System Research and Predictability Experiment (THORPEX) Interactive Grand Global Ensemble (TIGGE) data, has been developed for flood forecasting over the Huaihe River. The incorporation of numerical weather prediction (NWP) information into flood forecasting systems may increase forecast lead time from a few hours to a few days. A single NWP model forecast from a single forecast center, however, is insufficient as it involves considerable non-predictable uncertainties and leads to a high number of false alarms. The availability of global ensemble NWP systems through TIGGE offers a new opportunity for flood forecast. The Xinanjiang model used for hydrological rainfall-runoff modeling and the one-dimensional unsteady flow model applied to channel flood routing are coupled with ensemble weather predictions based on the TIGGE data from the Canadian Meteorological Centre (CMC), the European Centre for Medium-Range Weather Forecasts (ECMWF), the UK Met Office (UKMO), and the US National Centers for Environmental Prediction (NCEP). The developed ensemble flood forecasting model is applied to flood forecasting of the 2007 flood season as a test case. The test case is chosen over the upper reaches of the Huaihe River above Lutaizi station with flood diversion and retarding areas. The input flood discharge hydrograph from the main channel to the flood diversion area is estimated with the fixed split ratio of the main channel discharge. The flood flow inside the flood retarding area is calculated as a reservoir with the water balance method. The Muskingum method is used for flood routing in the flood diversion area. A probabilistic discharge and flood inundation forecast is provided as the end product to study the potential benefits of using the TIGGE ensemble forecasts. The results demonstrate satisfactory flood forecasting with clear signals of probability of floods up to a few days in advance, and show that TIGGE ensemble forecast data are a promising tool for forecasting of flood inundation, comparable with that driven by raingauge observations.

Web-Based Visualization for Hydrodynamic Model of Flood Retarding Basin: A Case of Doingping Lake

Hydrodynamics based numerical model is an effective way to simulate the movement of flood and its result can be visualized by many post-processing softwares. However, most of these tools are available only as local applications. This both limits the accessibility of the software to a specific machine and collaborative research. In this paper, we introduce a four-layer architecture for web-based visualization of numerical model. The application uses VTK(Visualization Toolkit) to render the numerical result and then the VRML standard is used to provide dynamic features over the web. By developing web-based visualization tools, it is possible for users to access the situation of flood wherever the internet is available, and can largely promotes the public services such as flood risk management.

Research on the Numerical Simulation of Zoning Flood Retarding and Sand Silting of Flood Plain in the Lower Yellow River

The 2-D water and sediment mathematical model which reflects flood retarding and sand silting of flood plain in the Lower Yellow River has been set up in this paper. Through carrying on 2-D water and sediment numerical simulation of the “96.8” typical flood, the authors studied influence of zoning flood retarding and sand silting on flood travel, flow structure of floodplain-channel and transver exchange of water and sediment. The simulating results in different conditions show that, adopting the zoning flood retarding and sand silting in the Lower Yellow River effectively worked on retarding flood and sharpening peaks in the flood retarding basin, guaranteed and expanded transver exchange of water and sediment in the floodplain and channel and maintained the river channel’s vigor. This can relieve “secondary suspended river” states in the Low Yellow River to a certain extent.

Hydraulic model for flood forecast of river basin with flood diversion and flood retarding ar-eas of Huaihe River

针对淮河流域河系特点, 建立淮河具有行蓄洪区河系洪水预报模型.干流河道洪水演进采用一维水动力学模型, 钐岗分流量利用分流曲线法推求, 利用虚拟线性水库法解决大洪水时支流洪水受干流顶托作用, 临淮岗闸作为水力学模型的内边界条件进行处理, 利用分流比法概化行洪过程, 行洪区内只有蓄满时, 才会有出流, 行洪区内的洪水利用Muskin-gum法进行洪水演进;由于蓄洪区进洪与出流均有闸门控制, 因而作为水库处理, 蓄洪区内不考虑洪水演进, 只进行水量平衡以判断进洪或者出流.以淮河干流王家坝至鲁台子河系为例, 建立淮河具有行蓄洪区河系水力学模型, 并与淮河具有行蓄洪区河系水文学模型在淮河2003-2008年洪水进行对比验证检验.结果表明, 所建立的淮河具有行蓄洪区河系洪水预报水力学模型在淮河洪检验取得较好的预报效果, 也证明了所建模型的合理性。;Hydraulic model of Huaihe River with flood diversion and flood retarding areas was developed for flood forecast.The in-put flood discharge hydrograph from the main channel to the flood diversion area is estimated with the fixed split ratio of the main channel discharge.The Muskingum discharge routing method is applied in the flood diversion area,and outflow can generate only after it reaches full storage.The flood flow inside the flood retarding area is calculated as a reservoir and inflow and outflow are cal-culated based on the water balance equation.Taking complex river basin between Wangjiaba and Lutaizi stations with flood diver-sion and flood retarding areas of Huaihe River as an example,with taking the Linhuaigang Project as inside boundary in flood rou-ting,Hydraulic model of Huaihe River based on one-dimension hydraulic model was developed.In order to testify the performance and rationality of the developed model,the representative flood events from 2003 to 2008 were forecasted with the developed hy-draulic model.Results show that the developed model performs well and is reasonable.

STUDY ON THE FLOOD CONTROL ABILITY OF A DRY DAM USED AS A FLOOD RETARDING BASIN IN A RIVER

We suggest to construct small scale dry dams in a river instead of a large scale dam in order to prevent a flood disaster and preserve a natural environment. In recent years, a flood control dam without a slide gate in spillway, known as a ’dry dam’, has been reviewed, planned and built in some sites. In this study, the effects of some slide gates in a bottom spillway which can be opened and closed automatically depending on hydraulic pressure called ’pressure gate’ for a dry dam are examined. In addition, width of a crest spillway gate is discussed to reduce rapid increase of flow discharge in the situation of overflowing. It is demonstrated that a dry dam has an additional ability to reduce damage from a flood surge. Small scale dry dams must be regarded as a flood retarding basin fitting to a natural environment. Therefore, construction of small scale dry dams is one of the powerful options to adapt a natural environment and global warming.

Comparison of flood management options for the Yang River Basin, Thailand

ABSTRACTThe Yang River Basin, Thailand, has always been subjected to flooding, but due to recent developments in land use there is an increase in the vulnerability in several parts of the river basin. To mitigate impacts of flooding, both structural and non‐structural measures can be taken. This paper discusses three scenario simulations focusing on flood retardation, retention, and damage mitigation measures. A main tributary was simulated by a process‐based hydrological model (SWAT) and coupled to the 1D/2D SOBEK river routing model. The first scenario focused on retarding basins, the so‐called natural flood storage, to reduce downstream flood flows by storing excess floodwater in low‐lying areas and releasing it after the peak has passed. The second scenario concerned a green river (bypass channel) to provide storage and drainage through a large, shallow retardation basin, and an outlet for water discharge from upstream. The third scenario concerned the effect of dikes to protect areas from inundation. The results show that the green river is the most appropriate solution since it can potentially reduce a 1% to a 10% per year flood event, with a reduction of peak discharges of 14% in comparison to 9.2% reduced by natural flood storage. Copyright © 2010 John Wiley & Sons, Ltd.

Environmental effects of agricultural conservation: A framework for research in two watersheds in Oklahoma's Upper Washita River Basin

Agriculture in the Upper Washita River Basin represents mixed crop-livestock systems of the Southern Plains. Research in the Little Washita River Experimental Watershed and the Fort Cobb Reservoir Experimental Watershed addresses interactive effects of variable climate, land use, and management on environmental quality. The Little Washita River watershed provides opportunities to explore impacts of flood retarding impoundments within a watershed. The Fort Cobb Reservoir watershed provides opportunities to study effects of agricultural conservation on a large eutrophic reservoir. Analysis of 1940 to 2005 data from the Fort Cobb Reservoir watershed showed that precipitation increased 33%, corresponding runoff increased 101%, and sediment yield increased 183% when comparing multi-year wet periods to multi-year dry periods. Depth to groundwater exhibited seasonal and interannual variation. A rapid geomorphic assessment indicated that unstable stream channels dominate the stream networks. Phosphorus concentration in streams was correlated to multiple attributes of the contributing areas, including contributing area, slope, stream density, and channel stability. Anticipated outcomes are improved understanding of environmental effects of conservation, new approaches to mitigation of water quality problems, and tools to support strategic placement of conservation practices on the landscape to achieve environmental goals.

NUMERICAL SIMULATIONS OF URBAN FLOODING DUE TO DIKE BREACHING

The flooding process of the Misumi district due to dike breaking of the Misumi River, occurred in July 1983, is simulated by a two-dimensional numerical model for urban flooding. The model employs the finite volume method on unstructured grid using flux-difference splitting (FDS) technique. Such characteristics of the flood plain as submerged/emerged topography, density and arrangement of buildings and houses, streets, flood retarding plantation as well as the characteristics of the river are considered in the simulations. It is shown that the model is capable of reproducing the complex inundation process in an urban area and hydrodynamic forces on buildings and houses with reasonable accuracy.

COMPREHENSIVE VERIFICATION OF NUMERICAL MODEL FOR URBAN FLOODING

A two-dimensional numerical model for uraban flooding is developed. The model is based on a numerical model with Finite volume method on Unstrucuted grid using Flux-difference splitting technique for 2D Flood flows (FUF-2DF model). The treatments of complicated flood plain geometries with sumberged/ emerged topgraphy, stuructures, road networks, flood retarding plantation etc. are incorporated into the model. In experiment, flow depths, velocities and hydrodynamic forces acting on structers in flood plain with complicated geometries were observed. The model is verified comprehensively against the experimental data, and it shows that the model can reproduce the complex behavior of the flow and hydrodynamic forces with reasonable accuracy.

A Geographical Study on Conversion of Irrigation Ponds into Flood Retarding Ponds at Tomoe River Basin in Shizuoka Prefecture

A Geographical Study on Conversion of Irrigation Ponds into Flood Retarding Ponds at Tomoe River Basin in Shizuoka Prefecture