Transportation network model with time delay for flood lamination strategy

Flooding due to rivers overflowing have affected this year many countries in the world. The engendered problems, due to their intensity, are relative to goods and persons safety, and often cause a sharp increase of the insurance costs, which is no more tolerable in the actual economic context. To prevent these problems, it is necessary to limit water heights downstream the streams. In the literature, numerous described works were done on flows modelling and management. The work presented in this paper, is interested in the quantitative management by means of floods diversion areas placed along the river and for which location and sizing are known. A management method computing the height of gates opening at each time step is proposed. The strategy is based on a transportation network model of the flood diversion area system including the time transfer delays. It allows the computation of the water volumes to be stored in time. Simulation results for different flood episode are discussed

Flood lamination strategy based on a three-flood-diversion-area system management

The flood lamination has for principal objective to maintain a downstream flow at a fixed lamination level. For this goal, it is necessary to proceed to the dimensioning of the river system capacity and to make sure of its management by taking into account socio-economic and environmental constraints. The use of flood diversion areas on a river has for main interest to protect inhabited downstream areas. In this paper, a flood lamination strategy aiming at deforming the wave of flood at the entrance of the zone to be protected is presented. A transportation network modeling and a flow optimization method are proposed. The flow optimization method, is based on the modeling of a Min-Cost-Max-flow problem with a linear programming formulation. The optimization algorithm used in this method is the interior-point algorithm which allows a relaxation of the solution of the problem and avoids some non feasibility cases due to the use of constraints based on real data. For a forecast horizon corresponding to the flood episode, the management method of the flood volumes is evaluated on a 2D simulator of a river equipped with a three-flood-diversion- area system. Performances show the effectiveness of the method and its ability to manage flood lamination with efficient water storage

A flood lamination strategy based on transportation network with time delay

Over the last few years, the frequency and intensity of floods has become more marked due to the influence of climate change. The engendered problems are related to the safety of goods and persons. These considerations require predictive management that will limit water height downstream. In the literature, numerous works have described flow modeling and management. The work presented in this paper is interested in quantitative management by means of flood expansion areas placed along the river and for which we have size and location. The performance of the management system depends on the time and height of gate opening, which will influence wave mitigation. The proposed management method is based on use of a transportation network with time delay from which the volume of water to be stored is calculated

Contribution to a flood situation management: a supervisory control scheme to reduce disaster impact

Inundations due to river overflows are becoming more frequent; management of flood is thus an important task belonging to the set of preventive measures allowing the protection of people and goods downstream. The flood situation management method proposed in this paper was designed to reduce the flood impact at its early arising stage. The river is supposed to be equipped with reservoirs in which water excess are stored and then released only when the flood episode ends. The supervisory control scheme allows calculating the water volumes through the use of a network flow. The management objectives such as the maximum discharge level allowed in the river, the order of priority for the reservoir storage or release; the measured levels and discharge in the river and in the reservoirs; and the assessed parameters such as time delays, are combined to configure the network flow. Then, the optimal flow in the network is computed and supplies the reservoirs’ gate opening setpoints. Finally, the method was applied to a simulated case for which the time delay during the flood varied and remained efficient for flood attenuation compared to the case when the gates were always open, thanks to the network configuration

Study of Global Change Impacts on the Inland Navigation Management: Application on the Nord-Pas de Calais Network

AbstractIn a global change context, governments in Europe want to promote alternative transports as inland navigation or railway instead of road transport. As example, in north of France, a shift of 20% from road transport to these alternative transport solutions is expected by 2050. Reaching this goal requires not only the delivery of new infrastructures and equipment, but also the design of efficient management strategies. By focusing on waterborne transport, it is thus necessary to improve the management of the inland navigation networks particularly the water resource. Indeed, the waterborne transport accommodation is strongly linked to the available water resource. This will be a challenging point in a global change context.The paper deals with the global change impacts on inland navigation networks. It aims at proposing new contributions as compared to past and current results of European projects on climate change and inland navigation. It appeared that the multi-scale modeling approach for inland navigation networks that was proposed during the last TRA Conference in Paris in 2014 is useful to determine the resilience of these networks and their ability to guarantee the navigation conditions during drought and flood periods. The proposed tools are developed to consider two space and time scales. The first approach is used to determine the water quantity that is necessary to accommodate the navigation during half a day, and the second allows the efficient control of the gates to keep the water level of each navigation reach close to its setpoint by rejecting disturbances and compensating the waves due to the lock operations. One example based on the real inland navigation network of the north of France is used to highlight the contributions of the multi-scale modeling approach

The Impact of Green Infrastructure (GI) on the Urban Water Cicle: a multi-scalar approach

Building urban resilience has attracted significant attention in recent years. In response to climate change, innovative technologies are emerging to help manage and attenuate flood risk. One frequently used approach to help build resilience capacity is Green Infrastructure (GI), which is considered an important strategy of urban planning aimed at enhancing sustainable development. Studies revealed that the various types of GI practices offer multiple benefits in addition to stormwater benefits, in widely varying geographic and climatic regions. This dissertation assesses the state-of-art on GI to discuss its effectiveness as a solution to tackling urban flood risk, as well as characterises a Spanish city (Vitoria-Gasteiz), as a city-scale case study. Vitoria-Gasteiz’s GI managed to improve and correct historical issues with urban flooding water quality, preserving its environmental and landscapes. Data from a monitored bioretention cell lysimeter, located at the National Green Infrastructure Facility (NGIF), Newcastle University, was analysed. The objective was to determine whether the bioretention cells offer an effective solution to urban flood management, by presenting its behavior in response to real rainfall events. Three rainfall events were chosen for analysis: the first one with a total rainfall of 26,2 mm, in which the lysimeter stored 80,7%; the second with 48,6 mm (of which 39,8 mm was only in 24,5 h), delaying the start of runoff by 12 hours and generating a lag time of 11 hours, storing 20%; and the third with 8 mm, where the lysimeter received 16 L and outflowed 100 mL. The bioretention cell characteristics were modelled in the software Storm Water Management Model (SWMM), to assess its hydrologic potential to manage runoff during flood events, from hypothetical wider catchment drainage areas. The best simulated SWMM scenario ratios were the 12,5:1 that showed, respectfully, a runoff peak and volume reduction of 30% and 32%, while the 25:1 showed a reduction of 3,45% and 16,5%.Num contexto de mudanças ambientais globais e de rápida urbanização, a construção de resiliência urbana tem atraído uma atenção crescente tanto de profissionais como de investigadores em planeamento urbano. Uma cidade precisa de avaliar e construir capacidade de resiliência para absorver, mitigar, adaptar e proteger a sua população, propriedades e infraestruturas a muitos tipos de perturbações, incluindo águas superficiais, mantendo ao mesmo tempo a sua organização e funções sociais, ecológicas e económicas. Estão a surgir tecnologias inovadoras para ajudar a gerir o risco de inundações, mas estas nem sempre são fáceis de implementar. Uma tecnologia frequentemente proposta para ajudar a construir capacidade de resistência é a utilização de técnicas de drenagem urbana sustentável, ou Infraestrutura Verde (GI, de Green Infrastructure, em inglês), como parte de um plano de gestão de águas pluviais. A utilização destas tecnologias é considerada uma importante estratégia de planeamento urbano, destinada a reforçar o desenvolvimento sustentável. De facto, os espaços verdes urbanos e a GI podem proporcionar múltiplos cobenefícios, para além dos benefícios das águas pluviais, e podem aumentar a resiliência urbana. Pensando nisso, esta dissertação avalia o estado da arte existente sobre GI, de forma a discutir as suas eficácias como soluções para o risco de inundações urbanas, bem como caracteriza uma cidade espanhola (Vitoria-Gasteiz) como um estudo de caso à escala de cidade, e, finalmente, analisa dados de um lisímetro de célula de bioretenção, localizado no National Green Infrastructure Facility (NGIF), na Universidade de Newcastle (Reino Unido), para determinar se a sua célula de bioretenção poderia ser uma solução eficaz para eventos de gestão de inundações urbanas, apresentando o seu comportamento em eventos de chuva reais. Além disso, ao modelar as características da célula de bioretenção no software EPA's Storm Water Management Model (SWMM), esta dissertação simula o potencial hidrológico da célula de bioretenção para gerir o escoamento de áreas hipotéticas impermeáveis à superfície. Através da revisão bibliográfica, verificou-se que muitos estudos revelaram que os vários tipos de práticas de GI oferecem múltiplos benefícios aos ecossistemas urbanos e ao escoamento urbano, em regiões geográficas e climáticas muito variadas. As instalações de bioretenção, por exemplo, podem reduzir 50% a 97% do volume total do escoamento, promovendo a infiltração para recarregar as águas subterrâneas com um efeito de purificação eficaz, intercetando poluentes e, também, promovendo a evaporação. Os cintos verdes de baixa elevação podem recolher o escoamento pluvial, retardar as cheias urbanas, e complementar as águas subterrâneas. Os pavimentos permeáveis podem ser utilizados para substituir as superfícies tradicionais das estradas de alcatrão. No entanto, as GI não possuem sempre o mesmo desempenho, dependem do clima e do regime pluviométrico de onde é implementada, e os seus benefícios a longo prazo e manutenção são ainda muito limitados. A combinação de infraestruturas convencionais cinzentas e verdes é importante para conseguir uma gestão de águas pluviais que funcione bem por períodos mais longos. Uma implementação bem-sucedida de GI, por exemplo, é a premiada cidade espanhola Vitoria-Gasteiz, onde o projeto e execução do “Cinturão Verde” desencadeou a Câmara Municipal a continuar a implementar outras GI. A cidade conseguiu melhorar e corrigir questões históricas da qualidade das águas urbanas e cheias, preservando o seu ambiente e paisagens e também melhorando a biodiversidade. Apesar da necessidade de trabalho árduo, é possível implementar Infraestruturas Verdes, procurando melhorar a vida dos seus cidadãos e das gerações futuras, uma vez que os inquéritos públicos indicam que 99% da população da cidade concorda que o “Cinturão Verde” e a suas GI melhoraram a sua qualidade de vida, uma vez que aumentou o número de espaços verdes, parques e jardins urbanos. Em relação aos dados analisados do NGIF, estes compreenderam um período de 9 meses de dados, nos quais a célula de bioretenção recebeu um total de 1.211,2 L como entrada e reteve eficazmente 52,7% do mesmo. Foram escolhidos três eventos pluviométricos no período dos dados: Setembro de 2020, com uma precipitação total de 26,2 mm em 2 dias, em que a saída no lisímetro foi atrasada em 17 horas, conseguindo armazenar 80,7%; Outubro de 2020, com uma precipitação de 48,6 mm em 3 dias (sendo que 39,8 mm foram apenas em 24,5 horas), atrasando o início escoamento em 12 horas e gerando um tempo de retardo do pico de escoamento em 11 horas, gerindo 20% do total de fluxo; e Abril de 2021, com uma precipitação total de 8 mm em 14 horas (sem chuvas anteriores por 43 dias), onde o lisímetro recebeu 16 L de entrada e teve como saída apenas 100 mL, resultando numa eficiência de 99%. De maneira geral, concluiu-se que células de bioretenção podem armazenar totalmente o volume de pequenos eventos de precipitação. Ou seja, a intensidade da chuva é a principal propriedade pluviométrica que influencia na eficiência da célula de bioretenção, com uma relação inversa (quanto maior a intensidade, menor a eficiência). Além disso, foram simulados diferentes cenários no software SWMM para a célula de bioretenção existente no NGIF, de acordo com as suas propriedades de laboratório, para gerir o escoamento proveniente de diferentes superfícies impermeáveis, a fim de descobrir uma razão ótima de área impermeável-célula de bioretenção. A melhor relação foi a de 5:1, que não gerou pico de escoamento e transbordamento de superfície, e geriu eficazmente 62% do fluxo total de escoamento. O cenário 12,5:1 mostrou uma redução de 30% do pico de escoamento e uma redução de 32% do volume de escoamento e o cenário 25:1 apresentou uma redução de 3,45% do pico de escoamento e uma redução de 16,5% do volume de escoamento. Os resultados, tanto reais como simulados, demonstraram que as células de bioretenção são infraestruturas verdes que, quando combinadas com sistemas de drenagem convencionais, podem ajudar as zonas urbanas a gerir os seus eventos de inundações e aumentar a sua resiliência, visto que os resultados demonstraram que essa GI pode atrasar o início do escoamento e os seus picos, além de diminuir os volumes totais. O lisímetro analisado é um de terra, portanto não possui nenhuma vegetação específica, por isso esta alternativa singular pode ser utilizada em todo o mundo, mostrando a sua implementação favorável e inclusiva

Reservoir management using a network flow optimization model considering quadratic convex cost functions on arcs

The allocation of water resources between different users is a hard task for water managers because they must deal with conflicting objectives. The main objective is to obtain the most accurate distribution of the resource and the associated circulating flows through the system. This induces the need for a river basin optimization model that provides optimized results. This article presents a network flow optimization model to solve the water allocation problem in water resource systems. Managing a water system consists in providing water in the right proportion, at the right place and at the right time. Time expanded network allows to take into consideration the temporal dimension in the decision making. Since linear cost functions on arcs present many limitations and are not realistic, quadratic convex cost functions on arcs are considered here. The optimization algorithm developed herein extend the cycle canceling algorithm developed for linear cost functions. The methodology is applied to manage the three reservoirs of La Haute-Vilaine’s watershed located in the north west of France to protect a three vulnerable areas from flooding. The results obtained with the algorithm are compared to a reference scenario which consists in considering reservoirs transparent. The results show that the algorithm succeeds in managing the reservoir releases efficiently and keeps the flow rates below the vigilance flow in the vulnerable areas

Remediation of accidental river pollution: strategies based on the use of reservoirs

The origins of water pollution are numerous, they cause alterations due to their high load of dissolved substances, micropollutants and toxic substances. Many studies have focused on the implementation of remediation measures for these types of pollution. In this work, the case of rivers subject to accidental pollution and the use of reservoirs for its remediation is studied. Two strategies are implemented: the storage of pollutants in the reservoirs and the dilution of pollutants by injecting in the river clear water from reservoirs. Both methods are applied to a river with one reservoir, and their impacts are studied for different flow levels

Constraint satisfaction problem based on flow graph to study the resilience of inland navigation networks in a climate change context

The T-Ten European program aims at optimizing the transport logistics in Europe by promoting alternative transport modes. Navigation transport offers a competitive and environmentally friendly alternative. Hence, it is foresaw an increase of the navigation transport demand that it will be necessary to accommodate. This will be very challenging particularly in a global change context where less available water resource is expected. A constraint satisfaction problem based on flow graph is proposed in this paper to study the resilience of inland navigation networks against increase of the navigation demand and extreme events. Drought and flood scenarios are simulated considering an network composed of five interconnected navigation reaches. The results show that the designed tools are adapted to the resilience study of inland navigation networks

A Study of the Feasibility of Autonomous Surface Vehicles

As climate change is continuing to negatively impact our environment, it is important for society to take a closer look at our oceans. Oceans are a significant part of our environment and contain telltale information about the systems that allow society to function. However, there are many difficulties and limitations in current ocean observation systems. In this report, we examine the use of autonomous surface vehicles to collect data and perform tasks in a variety of environmental areas