Development of rainfall-infiltration measurement system and recharge strategies for urban flooding areas: a case study of Delhi, India

Cities need strategies to cope with urban floods which arise due to encroachment of low lying areas and lack of storm water drains. The current study was carried out to evaluate the properties of urban soil, a key variable in the urban ecosystem which contributes to building more resilient cities. The study reveals that the soil profile of Delhi has low infiltration rates which are a cause for concern as they form a very important part of rainfall attenuation in storm events, the pervious cover is unable to contribute to ground water recharge, due to reduced subsurface. It was also found that accurate infiltration modeling requires site specific data based on local site conditions to assess the soil infiltration rate status in other similar areas. Therefore, a mathematical model has been developed based on different physical parameters of soil to calculate soil infiltration prediction rate. Various maps such as soil texture map, urban drainage pattern map, flooded junctions map and land use land cover map are studied to evaluate the need for sustainable drainage practices to mitigate urban flooding. Urban parks which are major sinks for rainfall, along with rejuvenation of water bodies need innovative management including active citizen partnership, urban local bodies and district park authorities to reduce urban flooding. Urban design guidelines, including urban open space planning standards need to be reviewed so as redesign utilization of open urban spaces.