Monsoon rains cause flooding along the Yamuna river
Monsoonal flooding is an annual event in India, but this July the National Capital Region (NCR) of Delhi has been hit particularly hard, as water levels in the Yamuna river broke records that had stood for 45 years. So far, 22 people are known to have died, whilst thousands more have been evacuated to temporary shelter over a two-week period of heavy rain and flooding (BBC, 2023a, AP News, 2023). Schools across the region were closed for several days, and many roads were inundated by rising waters, leading to travel disruption in the city of Delhi which is home to over 30 million people (Guardian, 2023; World Population Review, 2023).
Event overview
Several regions of India have already seen significant rainfall this monsoon season, with over 100,000 people being affected by flooding in Assam in June and the states of Himachal Pradesh, Punjab and Haryana seeing severe flood events, with at least 88 fatalities reported (FloodList, 2023a; BBC, 2023a). Even before this latest event, northern India was seeing record rainfall, which caused landslides and road closures in some Himalayan states, leading to the suspension of the annual Hindu pilgrimage of the Amarnath Yatra for several days in early July (BBC, 2023b).
Pre-monsoonal flooding such as this is becoming more common in the region, as explored in our event report on flooding in India and Bangladesh in 2022.
Figure 1: Satellite-observed rainfall animation showing 24-hour rainfall accumulations between 05 Jul 2023 and 17 Jul 2023. Rainfall data source: NASA GPM, 2023. Animation produced by JBA Risk Management, 2023.
Heavy rain began to fall in Delhi in early July, with the 24 hours leading up to 9 July seeing 153mm recorded, the highest July daily rainfall in the city in 40 years (Floodlist, 2023). This equates to 15 per cent of the total rainfall expected in an average monsoon season, according to local officials (Independent, 2023).
The rain caused record levels in the Yamuna river, which runs alongside some densely populated areas of the nation’s capital city New Delhi. The Central Water Commission’s warning system reached ‘red’ or the highest alert level on 12 July and remained at this level until 16 July (Indian Express, 2023). By the morning of 13 July river levels had exceeded the danger level at the Delhi Railway Bridge, beating the previous high set 45 years ago in 1978 (BBC, 2023b; Floodlist, 2023). The waters were still above danger levels on 18 July although levels were beginning to recede by this point (Times of India, 2023).
Impacts
To date, 22 people have been reported to have been killed by the Delhi floods (Guardian, 2023). Schools and colleges have been closed across the region, with relief camps housing over 5,000 people being set up in schools not immediately impacted by the flooding (Indian Express, 2023). In all, over 35,000 people were evacuated in a state-wide operation (Floodlist, 2023).
Travel has also been disrupted across the region, with more than 700 trains being cancelled due to waterlogged tracks (Hindustan Times, 2023). Arterial roads in Delhi were closed, as were some bridges and tunnels crossing the Yamuna, causing further problems for travellers and commuters (BBC, 2023a).
In Haryana, around 10,000 acres of farmland has been submerged due to the overflowing of the Yamuna. Crops including sugarcane, rice and vegetables were damaged, with farmers staring at heavy financial losses (Tribune India, 2023).
What factors contribute to flooding in Delhi
The monsoon typically occurs from July to September, bringing heavy rains to the region often in the form of intense showers and thunderstorms. The monsoon season is crucial for replenishing water sources and maintaining agricultural productivity but can also result in flooding.
Several factors contributing factors can exacerbate flooding in Delhi, including an overcrowded drainage system that struggles to cope with a rapid influx of water and leads to flooding in low-lying areas (Mongabay, 2023). Another factor is rapid urbanisation, especially in New Delhi, which has led to an increase of paved surfaces and in turn increasing runoff (Outlook, 2022). With the rapid urbanisation comes illegal encroachments and obstructions on riverbanks and drainage channels that hinder the smooth flow of water.
During significant flooding events, low-lying areas and poorly drained neighbourhoods in Delhi are particularly vulnerable. The government and local authorities often work to mitigate the impacts of flooding in the NCR, but challenges remain due to the city's rapid urbanisation and population growth (DDMA, 2023).
Climate change
Future climate projections suggest warming over the Indian Ocean will allow more moisture to be carried over the country during the monsoon season. This process is expected to drive a 5-10% increase in total rainfall. Furthermore, a warmer climate is also likely to facilitate much heavier periods of rainfall when precipitation does occur, along with longer breaks within the monsoon season (Royal Meteorological Society, 2023). This intensification of rainfall will lead to higher river flows making extreme flooding events such as this one more frequent in the future.
JBA’s future climate event set projects that Yamuna River flow rates at Delhi of this magnitude will become 50% more frequent by 2050 under the RCP4.5 scenario (1.5oC global mean temperature rise). This change will drive an increase of 26% in Delhi’s average annual river flood losses.
JBA’s India Crop Model
JBA has developed an India Crop Model, allowing you to capture potential crop losses under the Pradhan Mantri Fasal Bima Yojana scheme (Indian Prime Minister’s Crop Insurance Scheme or PMFBY) and the Restructured Weather Based Crop Insurance Scheme (RWBCIS). Figure 2 illustrates the exceedance probability curve of Haryana, an area affected by these latest floods, based on the 2022 PMFBY market data; the state of Haryana sees approximately 4.7 billion INR ($0.057 billion USD) and 4.2 billion INR ($0.051 billion USD) ground-up losses and insured losses respectively for a 1-in-50-year event.
Figure 2: Exceedance probability curve for Haryana based on the 2022 PMFBY market data.
This report is accompanied by a flood footprint for the event - detailing extents and depths of the flooding in areas affected. Download it via our Client Portal or request a copy by emailing eventresponse@jbarisk.com.
JBA helps re/insurers across the Indian market manage their risk. We have nationwide return period flood maps at 30m resolution for India and an India Crop Model – which captures multiple extreme weather perils, including flood and tropical cyclone damage – as well as our global flood modelling capability, which enables quantification of risk for every country in the world.
If you are interested in any of our products or services to improve your management of flood risk, please get in touch for more information. This report is covered by JBA’s website terms – please read them here.
References
AP News, 2023. Record monsoon rains have killed more than 100 people in northern India over two weeks. [Online]. Available at: https://apnews.com/article/india-monsoon-floods-deaths-8185e8e5b05fe9de76efc609928ec360 [Accessed 20 July 2023]
BBC, 2023a. Delhi floods: key roads underwater as Yamuna river swells. [Online]. Available at: https://www.bbc.co.uk/news/world-asia-india-66184551 [Accessed 17 July 2023]
BBC, 2023b. Flood warning in Delhi as rains batter north India. [Online]. Available at: https://www.bbc.co.uk/news/world-asia-india-66161591 [Accessed17 July 2023]
Delhi Disaster Management Authority (DDMA), (2023). [Online]. Available at: https://ddma.delhi.gov.in/ddma/floods [Accessed 21 July 2023]
FloodList, 2023b. India – Thousands Evacuate Floods in Delhi After Yamuna River Reaches Record High. [Online]. Available at: https://floodlist.com/asia/india-floods-delhi-july-2023 [Accessed 17 July 2023]
Guardian, 2023. India floods: monsoon rains leave 22 dead in north as Delhi sees wettest July day in decades. [Online]. Available at: https://www.theguardian.com/world/2023/jul/10/india-floods-new-delhi-rain-record-deaths [Accessed 17 July 2023]
Hindustan Times, 2023. Waterlogging on tracks: Over 700 trains, including 406 passenger trains, from July 7-15 cancelled. [Online]. Available at: https://www.hindustantimes.com/india-news/waterlogging-railway-tracks-trains-cancelled-heavy-rainfall-monsoon-101689236157989.html [Accessed 20 July 2023]
Independent, 2023. India’s national capital gets record single-day rain as several parts across country face severe downpour. [Online]. Available at: https://www.independent.co.uk/climate-change/news/delhi-rain-india-red-alerts-b2371949.html [Accessed 21 July 2023]
Indian Express, 2023. Delhi Flood News Live Updates. [Online]. Available at: https://indianexpress.com/article/cities/delhi/delhi-floods-live-updates-yamuna-water-level-kejriwal-8835583/ [Accessed 17 July 2023]
Mongabay, 2023. Behind Delhi’s floods is a history of encroachment and diminishing wetlands. [Online]. Available at: https://india.mongabay.com/2023/07/behind-delhis-floods-is-a-history-of-encroachment-and-diminishing-wetlands/ [Accessed 17 July 2023]
NASA Global Precipitation Measurement (GPM), 2023. Precipitation Data Directory. [Online]. Available at: https://gpm.nasa.gov/data/directory [Accessed 17 July 2023]
Outlook, 2022. Replan Cities Or The Poor Will Be Forced To Face The Music Of Floods In Urban Areas Every Year. [Online]. Available at: https://www.outlookindia.com/national/stench-diseases-damage-to-houses-urban-flooding-hits-poor-the-hardest-news-213235 [Accessed 21 July 2023]
Royal Meteorological Society, 2023. The Indian Monsoon in a Changing Climate. [Online]. Available at: https://www.rmets.org/metmatters/indian-monsoon-changing-climate [Accessed 17 July 2023]
Times of India, 2023. Delhi floods: Ring Road traffic returns to normal after Yamuna water level recedes; few restrictions left in place. [Online]. Available at: https://www.msn.com/en-in/news/other/delhi-floods-ring-road-traffic-returns-to-normal-after-yamuna-water-level-recedes-few-restrictions-still-in-place/ar-AA1dXY6B [Accessed 20 July 2023]
Tribune India, 2023. Over 10K acres of agriculture land flooded in Karnal. [Online]. Available at: https://www.tribuneindia.com/news/haryana/over-10k-acres-of-agriculture-land-flooded-in-karnal-524555 [Accessed 20 July 2023]
World Population Review, 2023. Delhi Population 2023. [Online]. Available at: https://worldpopulationreview.com/world-cities/delhi-population [Accessed 20 July 2023]
