Flood Retention Basins Research Articles

Toward Flash Flood Modeling Using Gradient Resolving Representative Hillslopes

AbstractIt is increasingly acknowledged that the acceleration of the global water cycle, largely driven by anthropogenic climate change, has a disproportionate impact on sub‐daily and small‐scale hydrological extreme events such as flash floods. These events occur thereby at local scales within minutes to hours, typically in response to high‐intensity rainfall events associated with convective storms. In the present work, we show that by employing physically based representative hillslope models that resolve the main gradients controlling overland flow hydrology and hydraulics, we can get reliable simulations of flash flood response in small data‐scarce catchments. To this end, we use climate reanalysis products and transfer soil parameters previously obtained for hydrological predictions in an experimental catchment in the same landscape. The inverted mass balance of flood reservoirs downstream is employed for model evaluation in these nearly ungauged basins. We show that our approach using representative hillslopes and climate data sets can provide reasonable uncalibrated estimates of the overland runoff response (flood magnitude, storm volume, and event runoff coefficients) in three of the four catchments considered. Given that flash floods typically occur at scales of a few km2 and in ungauged places, our results have implications for operational flash flood forecasting and open new avenues for using gradient resolving physically based models for the design of small and medium flood retention basins around the world.

New methodology for identifying sustainable freshwater resources for the production of green hydrogen

ABSTRACT Managing sustainable and digital transformations in the water industry is a challenge. The identification of freshwater resources for green hydrogen production is necessary for the energy transition away from fossil fuels such as oil and gas. This can be achieved through the sustainable flood retention basin (SFRB) concept for identifying optimal locations for the retention of surface water. This unbiased concept helps in conflict resolution between stakeholders with water rights. Moreover, it serves as a simple tool to produce a digital water supply atlas based on dimensionless parameters with the short names’ population density, location advantage, precipitation, groundwater level, water rights, SFRB, excess running water and proximity to networks. While the first five parameters can be determined during a desk study, the last three parameters require site visits for verification purposes. Germany was used as a representative case study country to demonstrate the proposed methodology to obtain a water atlas based on mapped weighted values. The Kaiserstuhl in Germany served as a worked calculation example indicating well above average potential for water storage using existing retention basins. The water atlas can be used to supplement a (green) hydrogen atlas, supporting decision-makers in building hydrogen infrastructure.

Upgrading of the flood retention basin Odenkirchen in Germany

The flood retention basin Odenkirchen on the river Niers in Germany was constructed around 60 years ago as consequence of a major, harmful flood event. The complete design and structures do not comply with up-to-date national regulations, the DIN 19700 [3], so that the owner, the Niers Association, decided to upgrade the basin. The upgrading works include different measures such as the adjustment of the reservoir operation management in consideration of the updated flood hydrographs and discharges as well as adjustments in respect to sewage disposal compensation. Latter purpose is an urgent consequence of the continuous urban development which led to a steady increase of the sewage discharges for which the required retention volumes cannot be realized locally. As part of the dam rehabilitation the reconstruction of the outlet works – a controlled weir with three bays and sluice gates – and construction of an overflow spillway as part of an embankment dam shall be realized. The complete project is dominated by the environmental restrictions comprising both environmental protection areas as well as requirements of fish passability and groundwater. The project area is located within a region with mining subsidence, groundwater management and high sediment loads.

Experimental and numerical analyses on the capacity and the control management of a large flood retention basin situated at the Inn River in Tyrol

The consideration of recent extreme events in flood statistics implies an increase of design flood peaks and discharge loads. With the focus on the 75 km long Tyrolean Inn River reach downstream the regional capital city Innsbruck, the harmonization of the 100-year flood peak and comprehensive 2d-hydrodynamic modelling simulations indicate the need for an extension of the existing flood protection measures. Lateral protection and object protection measures represent the only feasible option due to the confined areal conditions. However, an increase of the channel capacities would worsen the situation for downstream areas demonstrably. In order to counter this impact, it is planned to build several large controlled flood retention basins situated along the Inn River at the valley floor between Innsbruck and the border to Germany. The retention basin “Voldöpp” as one of these flood polders features a maximum capacity of 1.7 million m³ and a maximum design water depth of 3.6 m. According to current planning the inlet structure consists of four uniform weir fields with two gates each. Aims of the presented experimental and numerical analyses are the investigation of the flow characteristics in close range of the inlet structure, the weir capacity and a possible weir control management. Hydraulic model tests are accomplished at the scale 1:35 according Froude similarity and numerical modelling is done with the software FLOW-3D. Preliminary modelling results confirmed the functionality of the inlet structure and pointed out the need of further tests concerning the potential impacts of intense sediment transport and woody debris.

Raising New Orleans: Historical Analogs and Future Environmental Risks

Raising New Orleans: Historical Analogs and Future Environmental Risks

Predicting Multiple Functions of Sustainable Flood Retention Basins under Uncertainty via Multi-Instance Multi-Label Learning

The ambiguity of diverse functions of sustainable flood retention basins (SFRBs) may lead to conflict and risk in water resources planning and management. How can someone provide an intuitive yet efficient strategy to uncover and distinguish the multiple potential functions of SFRBs under uncertainty? In this study, by exploiting both input and output uncertainties of SFRBs, the authors developed a new data-driven framework to automatically predict the multiple functions of SFRBs by using multi-instance multi-label (MIML) learning. A total of 372 sustainable flood retention basins, characterized by 40 variables associated with confidence levels, were surveyed in Scotland, UK. A Gaussian model with Monte Carlo sampling was used to capture the variability of variables (i.e., input uncertainty), and the MIML-support vector machine (SVM) algorithm was subsequently applied to predict the potential functions of SFRBs that have not yet been assessed, allowing for one basin belonging to different types (i.e., output uncertainty). Experiments demonstrated that the proposed approach enables effective automatic prediction of the potential functions of SFRBs (e.g., accuracy >93%). The findings suggest that the functional uncertainty of SFRBs under investigation can be better assessed in a more comprehensive and cost-effective way, and the proposed data-driven approach provides a promising method of doing so for water resources management.

홍수저류지 설계를 위한 강우강도-지속시간-홍수량(IDQ) 곡선 해석

기후변화 및 도시화 등의 요인으로 인하여 증가하는 불확실성에 대처하기 위하여 건설되는 홍수저류지 형태의 치수시설물이 기존의 치수시설물과 연계되어 치수능력을 극대화 할 수 있는 설계기준과 절차의 제시를 위하여 본 연구가 수행되었다. 본류의 홍수위 증가량에 대비할 수 있는 저류지용량결정, 저류지용량이 주어져 있을 경우의 본류의 홍수위 저감효과산정 등에 적용할 수 있는 다양한 시나리오 하에서의 분석을 위한 절차를 제시하였다. 기존 설계홍수량 산정절차에 근거한 IDQ (Intensity-Duration-Quantity) 분석을 이용하여 임의지속시간에서의 설계홍수수문곡선 산정기법을 제시하였고 그 활용사례를 제시하였다. IDQ 분석을 통해 산정한 강우량을 기반으로 등가첨두 수문곡선을 산정할 수 있으며, 기존 수문곡선과 동일한 지속시간 하에서 하천의 수위가 높아질 수 있는 저빈도 수문곡선과, 기존 수문곡선과 동일한 첨두홍수량을 지니지만 강우지속기간의 증가로 인해 유출체적이 증가하는 수문곡선, 기존 수문곡선에 비해 하천의 수위 및 수문곡선의 부피 모두 증가하는 수문곡선 등 다양한 형태의 수문곡선에 대한 시나리오해석을 가능하게 한다. This research was carried out for suggesting design criteria and procedure for maximizing flood control capacity by building flood control facilities like flood retention basin built in connection with existing facilities in order to cope with increased uncertainty due to factors such as urbanization and climate change. We suggested the procedure for the analysis under the various scenarios applicable for the cases of determining retention basin capacity as provision for the flood water level increase in main river channel or estimating flood water level reduction effect when retention basin capacity is given. Procedure for estimating design flood hydrograph at any duration using Intensity-Duration-Quantity (IDQ) originated from the existing IDF, and its application example were provided. Based on rainfall estimated by the IDQ analysis, it is possible to calculate an equivalent peak hydrographs under various scenarios, e.g. lower frequency hydrograph under same rainfall duration with water level higher than existing hydrograph, hydrograph with same peak and higher volume due to increased rainfall duration, hydrograph with higher peak and volume than existing hydrograph, etc.

The History and Current Issues of Flood Retention Basin

The History and Current Issues of Flood Retention Basin

Predicting dam failure risk for sustainable flood retention basins: A generic case study for the wider Greater Manchester area

This study aims to provide a rapid screening tool for assessment of sustainable flood retention basins (SFRBs) to predict corresponding dam failure risks. A rapid expert-based assessment method for dam failure of SFRB supported by an artificial neural network (ANN) model has been presented. Flood storage was assessed for 110 SFRB and the corresponding Dam Failure Risk was evaluated for all dams across the wider Greater Manchester study area. The results show that Dam Failure Risk can be estimated by using the variables Dam Height, Dam Length, Maximum Flood Water Volume, Flood Water Surface Area, Mean Annual Rainfall (based on Met Office data), Altitude, Catchment Size, Urban Catchment Proportion, Forest Catchment Proportion and Managed Maximum Flood Water Volume. A cross-validation R2 value of 0.70 for the ANN model signifies that the tool is likely to predict variables well for new data sets. Traditionally, dams are considered safe because they have been built according to high technical standards. However, many dams that were constructed decades ago do not meet the current state-of-the-art dam design guidelines. Spatial distribution maps show that dam failure risks of SFRB located near cities are higher than those situated in rural locations. The proposed tool could be used as an early warning system in times of heavy rainfall.

Multi-label classification models for sustainable flood retention basins

It is becoming good practice to prepare risk assessments of river basins and coastal areas on a global scale. The novel sustainable flood retention basin (SFRB) concept provides a rapid classification technique for impoundments, which have a pre-defined or potential role in flood defense. However, most SFRB do often perform multiple functions simultaneously and thus are associated with multiple SFRB types. Nevertheless, previous SFRB classification systems assign each SFRB to a specific type relying on its main function. To handle the problem, this study aims to comprehensively assess the multiple functions of SFRB with the help of multi-label classification. The popular multi-label classifiers multi-label support vector machine (MLSVM), multi-label K-nearest neighbor (MLKNN) and back-propagation for multi-label learning (BP-MLL) were applied to predict the types of SFRB based on two data sets (one from Scotland and one from Baden). Findings indicate that multi-label classification schemes provide deeper insights into all potential functions of SFRB and help planners and engineers to make better use of them.

Application of spatial statistics as a screening tool for sustainable flood retention basin management

AbstractIn the context of climate change and the EU flood directive, this paper analyses and explores sustainable flood retention basins (SFRB) as adaptive structures contributing to water resources management and flood risk control. A dataset of 371 potential SFRB (including many operating reservoirs) characterized by 40 variables have been surveyed across central Scotland. However, the spatial properties of these SFRB, such as water storage (which relates to flooding depth) in different regions, are ambiguous. This paper uses geostatistics on the Scottish dataset. Spatial analysis showed that ordinary kriging, which is a spatial interpolation method, could be successfully applied to estimate numerical values for all key flood control variables everywhere in the study area. Moreover, the probability that certain threshold values relevant to flood control managers were exceeded can also be calculated by using disjunctive kriging. The findings provide an effective screening tool in assessing flood control using SFRB.

Feature selection methods for characterizing and classifying adaptive Sustainable Flood Retention Basins

The European Union’s Flood Directive 2007/60/EC requires member states to produce flood risk maps for all river basins and coastal areas at risk of flooding by 2013. As a result, flood risk assessments have become an urgent challenge requiring a range of rapid and effective tools and approaches. The Sustainable Flood Retention Basin (SFRB) concept has evolved to provide a rapid assessment technique for impoundments, which have a pre-defined or potential role in flood defense and diffuse pollution control. A previous version of the SFRB survey method developed by the co-author Scholz in 2006 recommends gathering of over 40 variables to characterize an SFRB. Collecting all these variables is relatively time-consuming and more importantly, these variables are often correlated with each other. Therefore, the objective is to explore the correlation among these variables and find the most important variables to represent an SFRB. Three feature selection techniques (Information Gain, Mutual Information and Relief) were applied on the SFRB data set to identify the importance of the variables in terms of classification accuracy. Four benchmark classifiers (Support Vector Machine, K-Nearest Neighbours, C4.5 Decision Tree and Naïve Bayes) were subsequently used to verify the effectiveness of the classification with the selected variables and automatically identify the optimal number of variables. Experimental results indicate that our proposed approach provides a simple, rapid and effective framework for variable selection and SFRB classification. Only nine important variables are sufficient to accurately classify SFRB. Finally, six typical cases were studied to verify the performance of the identified nine variables on different SFRB types. The findings provide a rapid scientific tool for SFRB assessment in practice. Moreover, the generic value of this tool allows also for its wide application in other areas.

Guidance on variables characterising water bodies including sustainable flood retention basins

Climate change is likely to increase the frequency of flood events, thus increasing the associated hazard. This may threaten some existing flood defences, which were designed and built prior to climate change being identified as a major issue; therefore, they may require modification to ensure their sustainability. The European Union recognises that member states may face significant challenges in implementing the Flood Directive and has responded with programs such as the Strategic Alliance for Water Management Actions, which aims to provide tools and guidance to aid the member states in implementation. Flooding is a complex spatial planning issue and therefore requires a range of tools and approaches to solve the problem. Solutions are likely to require sustainable (urban) drainage system (SUDS) solutions applied on a small scale combined with sustainable flood retention basins (SFRB) used on a large scale. This paper aims to provide guidance on 40 variables used to rapidly assess water bodies including SFRB in terms of their flood and diffuse pollution control purposes and potentials. The variables described should be the basis for the characterisation of SFRB, which are adaptive structural measures well integrated within the landscape promoting best management practice as part of a sustainable flood risk management strategy. The variables engineered, outlet arrangement, aquatic animal passage, land animal passage, basin and channel connectivity, seasonal influence, relative total pollution and flotsam cover are novel. The list includes sum parameter such as relative total pollution, which address as part of a simplified methodology several complex environmental processes.

Classification of different sustainable flood retention basin types

Using a revised version of a previously published expert classification system, a database of potential Sustainable Flood Retention Basins has been developed for Scotland. The research shows that the majority of small and former (often old) drinking water reservoirs are kept full and their spillways are continuously in operation. Utilising some of the available capacity to contribute to flood control could significantly reduce the costs of complying with the European Union Flood Directive. Furthermore, the application of a previously developed classification model for Baden in Germany for the Scottish data set showed a lower diversity for basins in Scotland due to less developed infrastructure. The classification system appears to be robust and has the potential, with minor modifications, to be applied across Europe. The principle value of this approach is a clear and unambiguous categorisation, based on standard variables, which can help to promote communication and understanding between stakeholders.

Classification of Flood Retention Basins: The Kaiserstuhl Case Study

The aim of this paper is to describe a conceptual classification model for Sustainable Flood Retention Basins (SFRB) used to control runoff in temperate climates. The author has defined a SFRB as an aesthetically pleasing (from the general publics' point of view) retention basin, predominantly used for flood protection and adhering to sustainable drainage and best management practices. The classification model concept was developed on the basis of an example database of 147 SFRB in Baden-Wurttemberg (Germany). The data were of high quality because the researchers had detailed local knowledge of the case study area. The model quality was improved on the basis of a more detailed case study of The Kaiserstuhl, a region (no clearly defined boundaries) with a very high density of flood retention basins (one SFRB per 2 km2; 51 sites in total). The model is based on an agglomerative cluster analysis and is intended to be used by landscape planners, environmental engineers, and environmental scientists to adequately classify the following different types of SFRB with the purpose of improving communication among stakeholders: Hydraulic Flood Retention Basin, Traditional Flood Retention Basin, Sustainable Flood Retention Wetland, Aesthetic Flood Retention Wetland, Integrated Flood Retention Wetland, and Natural Flood Retention Wetland. Despite the limited regional variation in flood retention basin characteristics within The Kaiserstuhl, the classification model example had an accuracy of 60 percent. A scoring template for the classification of future SFRB was devised on the basis of researcher experience, and this was optimized with a genetic algorithm.

Conceptual classification model for Sustainable Flood Retention Basins

The aim of this paper is to recommend a rapid conceptual classification model for Sustainable Flood Retention Basins (SFRB) used to control runoff in a temperate climate. An SFRB is an aesthetically pleasing retention basin predominantly used for flood protection adhering to sustainable drainage and best management practices. The classification model was developed on the basis of a database of 141 SFRB using the River Rhine catchment in Baden (part of Baden-Württemberg, Germany) as a case study. It is based on an agglomerative cluster analysis and is intended to be used by engineers and scientists to adequately classify the following different types of SFRB: Hydraulic Flood Retention Basin, Traditional Flood Retention Basin, Sustainable Flood Retention Wetland, Aesthetic Flood Retention Wetland, Integrated Flood Retention Wetland and Natural Flood Retention Wetland. The selection of classification variables was supported by a principal component analysis. The identification of SFRB in the data set was based on a Ward cluster analysis of 34 weighted classification variables. Scoring tables were defined to enable the assignment of the six SFRB definitions to retention basins in the data set. The efficiency of these tables was based on a scoring system which gave the conceptual model for the example case study sites an overall efficiency of approximately 60% (as opposed to 17% by chance). This conceptual classification model should be utilized to improve communication by providing definitions for SFRB types. The classification definitions are likely to be applicable for other regions with both temperate oceanic and temperate continental climates.

Expert system outline for the classification of sustainable flood retention basins (SFRBs)

The aim of this paper is to recommend a rapid classification system for sustainable flood retention basins (SFRBs) to control runoff in a temperate climate. The system should improve communication among engineers and scientists, and was developed with a general database (approximately 660 basins) and a very detailed database (56 basins), using the River Rhine catchment in the South of Baden (Germany) as a case study. The classification system can be used by civil engineers, environmental scientists and planners to determine the following types of SFRBs: hydraulic flood retention basin, traditional sustainable flood retention basin, sustainable flood retention wetland, aesthetic flood retention wetland, integrated flood retention wetland and natural flood retention wetland. The most important system variables were rainfall, dam height, flood water volume, elevation, dam length, flotsam, floodplain elevation, forest and animal passage. However, 34 variables were applied to determine the different types of SFRBs, which were predominantly used for hydraulic purposes.

Ecological effects of water retention in the River Rhine valley: a review assisting future retention basin classification

This review paper summarizes the ecological effects of the use of floodplains and flood retention basins to control river flow in the River Rhine (Rhein) valley. Early River Rhine regulation strategies including channel straightening are assessed. The subsequent disappearance of alluvial hardwood forests has been highlighted as the major disadvantage. The response of trees to more recent strategies such as ecological flooding is also assessed. Water quality and habitat improvements due to these ecological control techniques are identified as effective. The development of flood retention basin classification methodologies and floodplain management decision support systems particularly for the upper River Rhine Valley is recommended. The purpose is to aid communication among engineers and scientists, and to promote a holistic, integrated and international water resources management strategy, which would be relevant not only for the River Rhine valley but also for similar rivers in a temperate climate.

Classification methodology for Sustainable Flood Retention Basins

This paper recommends a rapid classification methodology for Sustainable Flood Retention Basins to control runoff in a temperate climate. Particular emphasis is given towards vegetated retention basins in Baden (Germany). The most important groups of variables were of engineering, environmental and land use nature. The classification methodology can be used by urban and landscape planners to determine the type of Sustainable Flood Retention Basin based on a total sum of weights obtained for 34 qualitative or quantitative variables. The following six types of Sustainable Flood Retention Basins (SFRB's) were defined: Hydraulic Flood Retention Basin, Traditional Sustainable Flood Retention Basin, Sustainable Flood Retention Wetland, Aesthetic Flood Retention Wetland, Integrated Flood Retention Wetland and Natural Flood Retention Wetland. The methodology was developed with a general database (approximately 460 basins) and a very detailed database (24 basins). Most of the thoroughly researched SFRB of the latter database are Traditional Sustainable Flood Retention Basins. The most important variables for Baden were Elevation, Dam Existance, Flotsam, Forest, Dam Length and Vegetation. These variables were applied to determine the type of Sustainable Flood Retention Basin (predominantly used for hydraulic purposes) with an error of <8% in comparison to the application of all 34 variables.

Constructed Wetlands for Water Pollution Control ‐ Processes, Parameters and Performance

Abstractconstructed wetlands are now recognised as an ecologically sustainable option for water pollution control. Natural wetlands are biologically diverse ecosystem. They provide an array of physical, biological and chemical processes to facilitate the removal, recycling, transformation or immobilisation of sediment and nutrients. Most of these processes are facilitated by the wetland vegetation, associated biofilms and micro‐organisms. Wetland ecosystems are complex and the interactions between abiotic and biotic components are fundamental to an understanding of the treatment processes. Constructed wetlands must therefore be designed to have the attributes of natural wetland ecosystems.The treatment efficiency of a wetland system requires a balance between pollutant loading rate and hydraulic retention time, which is also affected by the water quality and quantity of wastewater effluent or stormwater runoff: The size of a wetland will depend upon the volume of runoff, pollutant characteristics, desired level of treatment and the extent to which the wetland is expected to function as a flood retention basin. Water depth and extent of inundation will determine the types and species of aquatic plants. A combination of emergent, submerged and floating species should be selected.Pretreatment and detention times are crucial parameters to maximise pollutant removal efficiency. Sedimentation ponds are important in stormwater wetlands to remove particulates, but dense vegetated macrophyte zones are essential to enhance the removal of suspended solids and nutrients.Ecologists and engineers need to work together to maximise the treatment efficiency of constructed wetlands. Planners and landscape architects' must become involved to ensure that stormwater wetlands have a multi‐functional role in the urban setting.Constructed wetlands offer the ideal challenge to environmental engineers allowing for the integration of engineering and ecological principles to find the technical solution to fit both nature and society.