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Urban Flood Modelling : Recommendations for Ciudad Del Plata

Awakimjan, I. (2015) Urban Flood Modelling : Recommendations for Ciudad Del Plata.

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Abstract:Due to climate change and urbanisation urban floods have been increasing in frequency and size. An urban flood is when a rainfall event exceeds the capacity of the drainage in an urban area, consequently flooding it. Urban floods are known to lead to erosion of soil, pollution of the area and significant economic damage. With the increase in flooding frequency, urban flood models have been gaining interest as thy are a tool to understand floods and mitigate them. This thesis presents a list of recommendations for urban flood modelling in the Delta del Tigre district of Ciudad del Plata. This city in Uruguay is used as a pilot for a national water plan regarding drainage, flood protection, potable water and sewerage. The city was chosen because of its complex hydrologic situation involving impermeable soil and dykes. The soil forces water to run of instead of infiltrating and the dyke in the Delta del Tigre obstructs and at times stops the water from leaving the district. This leads to frequent flooding that, in addition to being very inconvenient, constitutes a danger for the residents in the city. As part of a diplomatic treaty between Uruguay and the Netherlands the aid of Dutch experts was requested, taking advantage of the long standing record of expertise in flood protection and water management the Netherlands possesses. The Dutch Risk Reduction team, a team of experts that advices governments on how to resolve urgent water issues, was asked to give advise for resolving the urban flood issues while at the same time assisting in creating the directive for the national water plan. Working in this context, this thesis concerns itself with a subset of the advise, namely recommendations for the modelling of urban flooding as a consequence of heavy rainfall. It in particular focuses on understanding the flood processes that take place in this complex urban environment. To give these recommendations a conceptual model was created and used. A conceptual model is essentially a blueprint for the construction of the model, containing all the necessary assumptions and methods of simulating the hydrologic processes. The challenges encountered during the creation of the conceptual model were used to identify the gaps in knowledge and to develop the recommendations. It was found that there is a lack of data, both in quality and availability. A section of the district lacks elevation data and the available measurements are distant from each other. The roughness coefficient, an important parameter for the flow of water, cannot yet be determined due to insufficient data on the surface shape and greenery. To cope with this a cell-based model has been recommended due to its usability and flexibility. It is usable in situations where the accuracy of data is low, while its flexibility allows for expansion in the future. A number of minor recommendations have been given in regards to the model, including the usage of simplified equations and the negligibility of smaller processes
Item Type:Essay (Bachelor)
Faculty:ET: Engineering Technology
Subject:56 civil engineering
Programme:Civil Engineering BSc (56952)
Link to this item:http://purl.utwente.nl/essays/68990
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