High-Resolution Waterlogging Mapping along Ghazipur Drain in Delhi: A UAV-Based Bathymetric Analysis Approach

Abstract

Environmental, economic, and public health problems are made worse by urban waterlogging especially post monsoon, in areas that are quickly urbanizing. This study employs UAV-based orthophotography and bathymetric data to examine waterlogging risks along the Ghazipur Drain in Delhi, India. High-resolution Digital Elevation Models (DEMs) with 5 cm ground sampling distance and bathymetric profiles reveal considerable drainage losses and sedimentation that reduce channel capacity by 25%. A map from the study highlights about 1,120 settlements in the low-lying areas, including Kalyan Puri, Jafrabad, Seelampur and Karawal Nagar, at the highest flood risk during monsoon months due to poor drain and high degree of urbanisation. When combined with bathymetry, UAV data is highly beneficial for acquiring the path, elevation, and bottom features of these outflows, revealing issues such as sedimentation, obstacles, and so forth. Orthophotos (pixel resolution = 0.05 meter) deliver detailed urban infrastructure visualizations, including drainage systems, to enable site-specific interventions such as dredging and channel widening. This method emphasizes the social and economic implications of waterlogging, such as property damage, transport disruption, and growing health hazards from waterborne diseases, which profoundly impact low- to middle-income communities.

As described in this work, the influence of UAV-bathymetry in urban drainage research can be considerable. This will translate into actionable insights to improve drainage infrastructure, reduce flood hazards, and increase urban resilience — useful information to planners and policymakers. This result confirms that UAV-bathymetry is a scalable, precise, and low-cost solution of urban waterlogging in the fast-developed cities around the world.