AbstractsGeography &GIS

Design opportunities for flash flood reduction by improving the quality of the living environment: A Hoboken City case study of environmental driven urban water management:

by A.C. Cruijsen

Institution: Delft University of Technology
Year: 2015
Keywords: urban water managment; blue-green measures; urban planning; SWMM; flash floods
Record ID: 1261175
Full text PDF: http://resolver.tudelft.nl/uuid:f433a5ce-8249-4976-a43f-a741b4ce2bf9


The overarching aim of this research project was to establish a sustainable urban water management design for Hoboken City to decrease vulnerability to extreme precipitation and improve urban quality. By carrying out a functional analysis of the area and the technical analysis of the water system, recommendations were made for soft and natural spatial solutions (i.e. blue-green measures). The base of the design is the existing urban environment, which is characterised by low area elevations, dense urban development, and high impermeability. The gravity based sewer system drains storm water into the Hudson River through combined sewer overflow valves. During high tide, the overflow valves close, preventing the storm water to overflow, whereby the surplus water remaining in the sewer pipes overflows in low-lying areas. Natural processes were used to recreate a naturally oriented water cycle. The main goals of the urban design were to reduce storm water floods, reduce the number of combined sewer overflows into the Hudson River, and improving the urban living environment. Urban quality was indicated by air quality, public green- and recreational space, and the reduction of urban heat island effects. The research question as a guide for the thesis reads: ‘What system of blue- green adaptation measures is most beneficial for Hoboken in terms of flood reduction and improving the urban quality?’ Various research methods are used to answer this question. To gain knowledge regarding urban water management and nature based flood adaptation measures, a literature review is conduced. tudies towards flooding and flood reduction in Hoboken were used as input for the water assignment. To design sets of blue-green measures, a functional analysis of the area is done using the six-layer approach for urban areas. With the approach, design opportunities and constraints for different layers are identified. The design strategies of appropriate blue-green measures for Hoboken are tested in a hydrology-hydraulic water management model. Results Hoboken suffers both flash flooding overwhelming the sewer system and storm surge. Low elevations and high groundwater levels influence infiltration capacity and efficiency of the drainage system. Combined sewer outlets with valves to the Hudson River carry excess water directly into the river during storms. When heavy rainfall coincides with high tide, excess water backs up in the sewer, causing flood nuisance in particular the low-lying areas. In terms of the required storage and drainage capacity, the water assignment for Hoboken is calculated. This technical assignment provides a rough measure of the required delay and storage capacity in urban areas for given rain events that exceed the existing storage and pumping capacity. With a basic hydrological model, the storage is determined on the basis of 100 years of precipitation data. The water assignment isn’t normative. It does not take detailed area characteristics, elevation profile and sewer layout into account and therefore cannot determine…