A Framework for Building Information Modelling and Geographical Information Systems Integrated Flood Risk Assessment of Urban Developments within a Watershed

Abstract

Rising to the challenge of climate change, this study focuses on pre-emptively identifying infrastructure vulnerabilities in flood-prone urban regions. Traditional Flood Risk Assessment (FRA) methods often neglect the complex interconnections within infrastructure systems. By synergizing Building Information Modelling (BIM) and Geographical Information Systems (GIS), a dynamic digital representation of built assets and their geospatial context is framed. This 'digital twin' undergoes scrutiny by an interoperable flood simulator, uncovering flood risks. The core objective of this study was to fashion a BIM and GIS framework for FRA within urban watersheds. This was realized by amalgamating BIM models of structures with terrain data of varying precision, resulting in a unified BIM-GIS digital twin. This twin, coupled with a versatile flood simulator, systematically evaluates flood risks. While developing an exhaustive software solution demands significant resources, this research effectively harnessed existing BIM and GIS tools to manifest the proposed framework. The viability of this framework was demonstrated and validated using Sector E-11 in Islamabad, Pakistan. Through simulating a historical flooding incident (July 2021), the framework was validated with a 0.02 RMSE between actual and simulated flood depths. Predictive simulations for the 100-year return period underscored vulnerabilities within the sector and shortcomings in hydraulic infrastructure that led to or exacerbated the urban flooding. Visual flood hazard maps depicting inundation extents were generated. In conclusion, the integration of BIM and GIS presents an efficient modelling approach that fosters stakeholder collaboration, yielding dependable, high-resolution FRA outcomes. These outcomes offer a visually vivid representation of infrastructure shortcomings and flood risks.