2019 CSCE Annual Conference - Laval (Greater Montreal)

2019 CSCE Annual Conference - Laval (Greater Montreal) Conference


Title
Developing a hydrological- hydraulic index (HHI) for the strategic allocation of Low Impact Development: a City of Toronto case study

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Author(s)
Mrs. Sahereh Kaykhosravi, York University (Presenter)
Dr. Usman Khan, York University
Dr. A. Mojgan Jadidi M., York University
Abstract

Developing a hydrological- hydraulic index (HHI) for the strategic allocation of Low Impact Development: a City of Toronto case study

S. Kaykhosravi 1, U. T. Khan 2, M. A. Jadidi3

1 Ph.D. candidate, Department of Civil Engineering, Lassonde School of Engineering, York University, Toronto, ON, Canada, saherehk@yorku.ca

2 Assistant Professor, Department of Civil Engineering, Lassonde School of Engineering, York University, Toronto, ON, Canada, usman.khan@lassonde.yorku.ca

3 Assistant Lecturer, Geomatics Engineering, Department of Earth & Space Science & Engineering, Lassonde School of Engineering, York University, Toronto, ON, Canada, mjadidi@yorku.ca

Low Impact Development (LID) is a sustainable and smart urban planning technique and is a popular method of stormwater management and flood mitigation. LID controls the source of the flood by decreasing the runoff volume, attenuating the peak flow runoff and delaying the time of concentration. To attain this, a series of measure such as: reducing the gradient of the land, increasing perviousness, providing storage volume, and increasing the surface roughness, are carried out at upstream sites to protect the downstream areas from flood hazard. However, among all factors, the degree of this protection significantly depends on the location of the LIDs. Identifying the sites that contribute the most in terms of flood generation is a spatiotemporal problem involving numerous spatial data. This identification helps water resources managers to allocate their limited resources to the sites that contribute the most to runoff generation and to effectively retrofit the downstream areas. Therefore, there is a need for a framework to help determine sites where there is a higher demand for LIDs. The focus of the current research has been limited to finding feasible sites for LIDs in the detailed design and not in the strategic planning stage of the LID projects. In this research, we propose a spatiotemporal decision-making model for strategic allocation of resources for LIDs using commonly available spatial and temporal data. This decision-making model uses an analytical hierarchy process framework that combines two developed indices to determine the LID priority map within the City of Toronto: (1) the hydrological index representing the potential of the site for runoff generation, (2) the hydraulic index indicating the time of concentration of the catchments. Preliminary results show that the two indices prioritize several hotspots in the study region that have a high potential for flood risk and require LID. Historical flood data is used to verify the model results.