Urban Flooding: Insights from Hyderabad

Hyderabad faced extreme flooding and water stagnation across the city following a 24-hour severe rain event.


Last year, in October 2020, 192 mm of rainfall overwhelmed storm drains and spilled onto the streets. Roads and expressways turned into rivers and carried water into homes and businesses causing loss of lives and property damage of up to INR 5000 crore.

The rainfall is the heaviest October rainfall on record since 1903.

It is around 70% of the historic rainfall of 1908 (432 mm in 36 hours) which caused catastrophic floods and led to the new plan for Hyderabad by the Nizam’s administration.  

Today Hyderabad is a world class city enmeshed into global financial and information networks. The city has consistently been ranked as the most livable Indian city for 5 years running in the Mercer list.

Yet Hyderabad, like many other Indian cities, continues to struggle against repeated and increasingly intense flood events.  

WRI India’s on-going research offers insights on the nexus of rapid urbanization, climatic uncertainties and the increasing frequency of natural disasters such as floods and droughts. 

Incidences of urban flooding are brought about by the confluence of growing impermeable cover, loss of natural spaces, location of development in the paths of water flow, solid waste dumping on water bodies and severe rain events. 

City landscapes which are unable to absorb or manage rainfall lead to chronic urban flooding. Recurring flood events diminish the quality of life of urban dwellers, damage property and lower property rates and pose health risks from water borne diseases.

High rainfall is not the only reason for flooding. There are other underlying reasons for such floods in most cities in India including Hyderabad.

1. Paving the way for floods

Rainwater infiltrates into the ground, flows as surface runoff and evapotranspirates into the atmosphere. Urban areas with impervious surfaces such as roads and buildings eliminate infiltration, reduce evapotranspiration, thereby drastically increasing surface runoff.  

As cities grow buildings and roads are constructed on open spaces and natural ecosystems. Areas which absorbed rainwaters are replaced by hard, impermeable surfaces which increases volume and speed of runoff.  

Hyderabad’s built-up cover has increased by 41% within 0-20 km of the city center and by 129% in the 20-50 km region between 2000-2015.  

Residences built in low lying wetland zone between Kumini Lake and Chinna Maisamma lake are vulnerable to flooding. Photo by Google Earth Pro.

2. Building in the path of floods

During rain events urban development including  public infrastructure  (bus depots, roads, metro rail, airports, etc.) located on low-lying areas (floodplains, lake beds) face increased flood risk.

Increasing demand for residential zones, commercial and business establishments has led to extensive building activity near lakes, streams and wetlands. The flood cushion offered by these natural spaces has been lost and buildings in these areas face high flood risk.

Extensive addition of impervious layer near Umda Sagar will impact runoff in the area. Photo by Google Earth Pro

Google Earth Engine timelapse for Hyderabad showing increase in urban extents (1984-2018)

3. Storms of uncertainty

Climate change driven rainfall variability is increasing with rainfall equivalent to monthly/seasonal averages falling within a few days.

Hyderabad faced 192 mm of rainfall over 24 hours which is  76% higher than October’s normal for the entire month.  

Urban resilience, with a focus on effective flood mitigation and flood control, is still missing in the city’s development agenda. Furthermore, the probability of increased frequency and severity of extreme rainfall and flood events due to climate change is not yet an integral part of Hyderabad’s development story or disaster responses.

Vision of a Flood Resilient Hyderabad

Hyderabad continues to be a vibrant, cosmopolitan, global city. But the future is likely to bring more frequent bouts of intense and extreme rainfall.

How can Hyderabad prepare to become more resilient in this erratic future? So that urban dwellers, urban property and infrastructure are protected from the devastating impacts of rain and floods such as faced on 13 October 2020.

Water prudent urban development is gaining prominence with cities adopting  hybrid approaches of integrating or replacing grey infrastructure with new blue-green solutions . This  integrated blue-green-grey approach  makes use of natural systems (either intact or engineered) to provide urban service. For example, parks/squares/rain gardens absorb and slow stormwater runoff, wetland/ lakes retain stormwater.

Many global cities have successfully transformed their hard streets into porous, green landscapes as part of  green streets  programs. Street trees,  permeable pavements  bioswales and retentions planters  and rain gardens at local street scale help build resilience. 

At a neighborhood scale, existing open/vacant spaces such as city parks, playgrounds and post-industrial zones can a bsorb flood waters when converted into water-prudent landscapes  using green interventions.

City-wide strategies to mitigate urban floods through nature-based stormwater management such as Vancouver’s hybrid  rain city strategy  focus on adaptive management. Integrating urban planning with blue-green-grey solutions, traffic, and hydraulic analysis with sound investment strategies help reduce flooding and improve urban livability. 

Residences built in low lying wetland zone between Kumini Lake and Chinna Maisamma lake are vulnerable to flooding. Photo by Google Earth Pro.

Extensive addition of impervious layer near Umda Sagar will impact runoff in the area. Photo by Google Earth Pro