Urban waterlogging risk susceptibility within changing pattern of rainfall intensity in Delhi, India

Waterlogging and floods are among the most recurring and devastating natural hazards likely to occur more frequently in cities due to climate changes and rapid urban growth. High-intensity precipitation and subsequent waterlogging arouses negative physical and socio-economic challenges in urban areas. Mainstreaming disaster risk assessment is fundamental to reduce the related loss. In the lieu of changing characteristic of meteorological, hydrological and socio-economic condition of Delhi city, this study entails much needed analysis of daily rainfall intensity, frequency and duration, waterlogging area estimation, hazard and vulnerability mapping and spatial risk susceptibility mapping in frequently affected area of North Delhi as a study region. Microspatial scale assessment at urban municipal wards using analytical hierarchy process for weight criteria assignment was done by selecting 19 parameters. The final risk susceptibility map revealed that the north and north-western part of North Delhi are at very high risk which is evident with frequent waterlogging incidences too. An area of 282.56 square kilometres accounting 52.75 per cent is estimated to be at high- and very high-risk category. The high-risk areas demand employing pumping stations at locations precisely such as Jahangirpuri, Begampur, Burari, Bawana along with Rohini Sector 20, 21, 23 and 24 as immediate mitigation measure. The result also suggests that the moderate (39.8%)- and low-risk zones (7.57%) have comparatively lesser significant portion of the total area, but the problem intensifies due to encroachment of drains, dense informal settlement neighbourhood and increase in urban built-up increasing the impervious surfaces. The study also demonstrated that the city system demands regular maintenance of its sewage pipes, cleaning of inlets and taking care of waste disposal as it clogs the drain and increases risk of waterlogging. This study models the microlevel comprehensive investigation for disaster risk reduction to be used further for cities worldwide.

Graphical abstract