What Has Delhi Learnt Since Yamuna's Record Rise In 1978? Here's What Experts Say

Delhi Flood: The water level of Yamuna had risen to an all-time record high of 207.49 metres in 1978, resulting in catastrophic floods in the national capital. The current level is over 207.55 metres.

Explaining what Delhi has learnt since Yamuna's record rise in 1978, experts told ABP Live that left and right bank marginal embankments have been constructed to protect the trans-Yamuna regions from catastrophic floods, and reservoirs built, among other measures.

Source : PTI

Delhi Flood: The level of the Yamuna river in Delhi has breached the 1978 record-high level of 207.49 metres, which resulted in catastrophic floods in the national capital. The current level of Yamuna is over 207.55 metres, according to ABP News sources. An evacuation process is underway to relocate people living in flood-prone areas to safer regions. The 1978 floods affected areas spanning 43 square kilometres around the National Capital Region (NCR).

ABP Live spoke to Dr Somil Swarnkar, Assistant Professor, Department of Earth and Environmental Sciences (EES), IISER Bhopal; Dr Anjal Prakash, Research Director, Bharti Institute of Public Policy, Indian School of Business and IPCC Author; and Mr Praveen Tiwari, Co-Founder, Netsol Water Solutions, Greater Noida, Uttar Pradesh, and asked them about what Delhi has learnt since Yamuna’s record rise in 1978.

“If the water level breaches the 1978 flood level in the Yamuna river, there is a high likelihood of floods occurring in the surrounding areas. Floodwaters can submerge low-lying areas, including residential neighbourhoods, agricultural fields, and infrastructure like roads and bridges. This can disrupt transportation, compromise access to essential services, and pose a threat to human safety,” said Tiwari. He spoke to ABP Live on Tuesday, a day before the 1978 level was breached.

Dr Prakash also said on Tuesday that flooding can result in significant damage to infrastructure, homes, and agriculture, along with potential loss of lives.

However, Dr Swarnkar disagreed. On Wednesday morning, a few hours before the 1978 level was breached, he said that a flood similar to the 1978 event is unlikely due to increased heights of embankments and shanks guarding NCR's low-lying areas. He also explained that it is possible that the people living near floodplains will be affected the most in the event of the 1978 water level being breached due to increased intensity of rainfall events and altered land use and land cover conditions.

“The 1978 floods touched the 207-metre water level mark. We have witnessed 2010 and 2013 flood events that crossed the 207-metre water level mark. A flood situation similar to the 1978 event is unlikely due to the increased heights of embankments and shanks guarding NCR’s low-lying regions. It is possible that those people who are living near floodplains would be mostly affected in the event of the 1978 water level mark being breached due to increased intensity of rainfall events and altered land use and land cover conditions.” Dr Swarnkar said.

Explaining what Delhi has learnt since Yamuna's record rise in 1978, Dr Swarnkar said that left and right bank marginal embankments have been constructed to protect the trans-Yamuna regions from catastrophic floods. "Further, these flood-protecting structures are strategically located in the NCR, protecting low-lying regions."

Dr Prakash said that the measures taken after 1978 to address the rising Yamuna river levels during heavy rainfall include the construction of embankments and flood control channels, dredging and widening of the riverbed, building reservoirs and storage structures, and the implementation of drainage systems. He also said that the construction of reservoirs, canals and drainage systems has helped divert excess water to other areas for various purposes like irrigation, drinking water supply, or industrial use. "Improved flood forecasting and warning systems help monitor the river's water levels and issue alerts when necessary. These efforts are aimed at mitigating the impact of excessive rainfall and preventing floods in the surrounding areas."

Tiwari explained that the first significant step taken to address the issue of rising Yamuna levels during heavy rainfall was the implementation of the Yamuna Action Plan (YAP) in 1993. The plan was aimed at reducing pollution and improving the river's flow. He also said that the plan involved setting up sewage treatment plans, improving solid waste management, and implementing strict regulations on industrial effluents.

"In addition to the Yamuna Action Plan, various flood control measures were undertaken to manage the rising water levels. These included the construction of embankments, bunds, and floodwalls along vulnerable areas of the river. Dredging and widening of the river channel were also carried out to increase its capacity to accommodate higher water volumes during monsoon seasons. Moreover, the government has emphasised the importance of watershed management and afforestation in the Yamuna basin to reduce soil erosion and enhance water retention. The implementation of rainwater harvesting systems and the revival of traditional water bodies have also been encouraged. Despite these efforts, challenges persist, including encroachments along the river, unauthorised construction, and industrial pollution. Continued vigilance and sustained efforts are required to effectively address the rising Yamuna levels and ensure the long-term sustainability of the river ecosystem," Tiwari said.

According to Tiwari, other efforts made in Delhi to prevent and mitigate flooding include the development of various facilities. For instance, a well-established drainage infrastructure consisting of storm water drains and canals has been expanded to accommodate increased rainfall and effectively channel excess water away from the city. He said that flood control embankments constructed along the Yamuna river serve as barriers to contain floodwaters and protect Delhi from inundation.

“To ensure timely response and preparedness, advanced flood monitoring and warning systems have been implemented, utilising modern technologies to monitor rainfall, river levels, and weather patterns. These systems enable authorities to issue timely warnings, facilitating evacuation and emergency response. Moreover, the implementation of floodplain zoning regulations has restricted construction and development in flood-prone areas, reducing vulnerability and ensuring proper land use planning. Riverfront development projects have also been initiated, focusing on the beautification of the Yamuna riverbanks while enhancing flood resilience and providing recreational spaces for the public," Tiwari explained.

However, Tiwari said, further actions are necessary to strengthen flood prevention and mitigation in Delhi. “These include integrated water management practices such as rainwater harvesting, groundwater recharge, and wastewater recycling to manage water resources effectively. Sustainable urban planning strategies should be embraced, incorporating measures like green infrastructure, permeable surfaces, and proper land use planning to minimise flood risks and enhance resilience against future floods.”

According to Dr Prakash, it is important to strengthen infrastructure, enhance early warning systems, implement sustainable urban planning, and improve coordination between relevant authorities. “Additionally, investing in flood-resistant infrastructure and promoting community awareness and preparedness would contribute to better flood prevention and mitigation in Delhi.”

Dr Swarnkar said that in 1978, critical flood protection structures were not present, because of which the devastating floods occurred. He explained that floodplain management and proper marking in terms of water levels are essential to protect people from the effects of floods, especially those living closer to the Yamuna floodplains, where the chances of flooding are higher. 

The amount of rainfall that caused Yamuna to cross the 207-metre level in 1978 can create higher surface flow in 2023. Here’s why

Dr Swarnkar explained that since the land use and land cover, which refer to the way people are using the land, and the physical land type, respectively, has been altered drastically in the last 45 years, the amount of rainfall that caused the Yamuna river to cross the 207-metre mark may create higher surface flow in 2023. This is because there is reduced infiltration of water into the ground. 

Citing urban flooding in places like Bengaluru, Chennai, Hyderabad and Indore, he said these events were caused by high-intensity rainfall and altered land use and land cover. 

Swarnkar explained that in the instances in which hydrological connectivity is altered due to construction and change in land cover and land use conditions, the excess water will inundate the surface and create multiple flood-linked hazards such as malaria. Moreover, excess water can be diverted into the sewer system.