Risk-informed planning essential to prevent floods in Kochi

A house flooded in Kerala during the floods of 2018.

Banner image: As climate change makes weather patterns more and more erratic, it is important crucial to understand factors that cause flooding at a localised level. Photo by Dilshad Roshan/Wikimedia Commons.

  • In August 2018, Kerala experienced the worst floods in its history since 1924. Altogether 5.4 million people were affected, of which 480 died, 1.4 million were displaced, and hundreds were injured, while many were reported missing.
  • As climate change makes weather patterns more erratic, it is crucial to understand factors that cause flooding at a localised levels. According to experts, for a coastal city such as Kochi, that lies at sea level and is interspersed with a network of canals and low-lying wetlands, making risk-informed plans is vital.
  • Studies have shown that structures built on wetlands, pollution leading to choking canals, and improper constructions causing siltation in backwaters stem the natural flow of water, leading to flood-like situations in the city.

In the months of June, July and August 2018, Kerala experienced the worst floods in its history since 1924. During this time, the state received rainfall that was 42 percent more than the normal average. The heaviest rainfall period was between August 1-20 2018, when, according to a November 2021 report of the Comptroller and Auditor General of India (CAG), Kerala witnessed rainfall that was 164 percent above the normal average – nearly 771 mm of rain. The torrential rain triggered several landslides, forcing the release of excess water from 37 dams across the state, further aggravating the flood impact.

All 14 districts in the state were impacted, of which seven districts – Ernakulam, Alappuzha, Idukki, Kottayam, Pathanamthitta, Thrissur and Wayanad were notified as wholly flood-affected. The floods hit 5.4 million people, of which 480 people died, nearly 1.4 million people were displaced, hundreds were injured, and many went missing. According to government reports, the state incurred a loss of nearly Rs. 26,720 crore (Rs. 267.2 billion).

A man walks on a flooded road in Kerala during the floods in 2018.
The floods in 2018 affected nearly 5.4 million people and displaced almost 1.4 million people. According to government reports, the state incurred a loss of nearly Rs. 26,720 crores (Rs. 267.2 billion). Photo by Praveenp/Wikimedia Commons.

Kochi, a major port city in the state, suffered severe damage as well. During the flood, many low-lying areas were inundated and canals overflowed with water seeping into people’s homes and shops.

Jacob Santhosh, a 55-year-old Right To Information (RTI) activist who resides at Methanam, Alangad, a locality in Kochi with a line of backwaters along its length, said they had never imagined such a situation would arise in their neighbourhood. “We left just before the worst hit us. The water had touched very high levels and was almost up till my shoulder inside my house,” he said, pointing at a watermark on the wall outside his house. “All my furniture in the lower part of the house floated away or was damaged.”

Santhosh’s neighbour, Prasad MG, owns a small country boat he often uses to go fishing in the backwaters. “I was repairing my net when things started looking really bad,” he said, recalling the afternoon of August 15, 2018.

Prasad ended up rescuing around 40 families. “I swam with my boat to the flooded houses. Altogether, five people can sit on the boat at a time,” he explained. He took them to a nearby church, which had set up a flood relief camp. “I must have made at least ten trips that day, along with other boats doing the same work. We continuously worked hard for over two days,” he said.

Fishers played a prominent role in the safety and rescue efforts in the flood-hit regions across the state. Ever since, Kerala has witnessed extreme rainfall events every subsequent year since 2018.

Jacob Santosh (left) and Prasad MG (right) withnessed the damage caused by the flooding in 2018. Prasad MG rescued 40 families on his small country boat which he uses for fishing.
Jacob Santosh (left) and Prasad MG (right) witnessed the damage caused by the flooding in 2018. Prasad MG rescued 40 families on his small country boat, which he uses for fishing. Photo by Supriya Vohra for Mongabay.

“Things are so bad now, that a small spell of high rainfall will flood our backwaters entirely,” Santhosh said.

The sixth assessment report of the International Panel for Climate Change (IPCC) states that coastal cities are at risk of rising temperatures in the Arabian Sea. Climate scientists have been quoted in the media commenting on how the sea level along the Kochi coast is rising at par with the global rise in sea levels, at the rate of three cm per decade. This, they say, is equivalent to 17m of land along the coast being carved away every decade. Coastal erosion is a very real threat, eating away at Kerala’s land. The region in Chellanam, on the outskirts of Kochi is inundated with floods every monsoon, causing a continuous erosion of its coastline.

Savita Vijayakumar, a political ecologist from Kochi, says that on a global scale, climate change-induced extreme weather events are becoming a common sight. “When it meets a specific geography at the local scale, it creates a manmade disaster because natural safeguards including forests that prevent erosion and mangroves that prevent flooding of the landscape have been are removed and replaced with vulnerabilities that cause these issues.”

The geography of Kochi

Elaborating on Kochi’s geography, Savita says that considering where Kochi is located, it is very hard to say where the waterline ends, and the land begins, as both are enmeshed. “It is a place that straddles the idea of ‘in-betweenness’, a place that straddles between land and water.”

Geographically, Kochi lies on the southwest coast of India, in Kerala’s central region in the district of Ernakulam. It is bounded by the Arabian Sea on the west, and its eastern regions are largely urbanised. Much of the city lies at sea level, with a 48-km coastline. The average altitude towards the eastern side is 7.5m above mean sea level (MSL) and less than one metre to the west.

The land slopes gradually from east to west. The central part of the city has a flat terrain interspersed with a network of canal systems linking to the backwaters. One of the characteristic physical features of Kochi is its expanse of backwaters and low-lying wetlands. The backwaters form a part of the Vembanad water basin of central Kerala. Covering a length of 96.5 km and a wetland area of 2033.02 km², Vembanad is one of the largest freshwater lakes in Asia and the second largest Ramsar site in India. The lake is bordered by the districts of Alappuzha, Kottayam and Ernakulam. It is situated at sea level and separated from the Arabian sea by a narrow barrier island.

Kochi city lies at the lake’s outlet to the sea.

Climatically, the maximum annual rainfall in the region is around 3,000 mm. Heavy showers during the monsoon cover the entire state, sustaining a system of rivers and estuaries originating from the Western Ghats. These rivers, with the Periyar amongst them, transport the sediments from highlands and midlands to the plains and discharge them into the Arabian Sea. The interaction between the river discharge and the tidal forces helps the sediment deposition, thereby directly influencing the creation of the lagoon system and landforms of Kochi.

The Vembanad lake is one of the largest freshwater lakes in Asia, with a wetland area of 2033.02 The city of Kochi lies at the lake’s outlet to the sea. The city’s canal system is linked to the backwaters, which are a part of the Vembanad water basin.

Kochi thus straddles the backwaters, encompassing the northern end of a peninsula, several islands, and a portion of the mainland. Since the estuaries and canals are connected to the sea, all water bodies are influenced by high and low tides. From a temporal perspective, Savita says, “The wetness is a key characteristic of the city.”

What causes Kochi’s floods?

In November 2021, the CAG released a report titled “preparedness and response to floods in Kerala.” The report dissected various human-induced factors that led to the floods in August 2018 in Kerala. The report blamed lack of planning and capacity building, lack of flood forecasting stations, lack of capacity surveys of reservoir dams, and change in land use patterns as some of the broad reasons for the flood impact.

In Kochi, experts point to changing land-use patterns, waterlogging, siltation of water bodies, choked canals, constructions on wetlands and the influence of tides for the floods.

Unchecked constructions and no risk-informed planning

According to the 2021 CAG report, between 1985 and 2015, the built-up area in Ernakulam district increased by 212 percent, and water bodies decreased by nearly 17 percent. The report blamed the drastic increase in built-up area and a reduction of water bodies as one of the reasons for the high impact of the flood. “Such an increase in the built-up area, accompanied by a decrease in water bodies adversely affects the flood runoff, intensifying the inundation during heavy rain,” the report stated.

Sekhar Lukose, Member Secretary (ex-officio), Kerala State Disaster Management Authority and Head of Kerala State Emergency Operations Centre, said that Kochi city developed organically, without a risk-informed plan. “There is a bypass road connecting Aluva to Edapally by the Lulu Mall. Everything west of that road is low-lying land and not conducive for construction,” Lukose told Mongabay-India.

Explaining the geomorphology of the area, Lukose said, “These landscapes were earlier wetlands, natural flood retention entities by geomorphology. They were located at the mouth of the lake, which opens into the sea and would deposit clay and sediments. Roads should not be constructed here as it obstructs the natural flow of the water. There was no land-use planning with embedded risk information at that point.”

Reshma Mathew, a Kochi-based independent architect, explained that most public infrastructure projects in the city are contractor driven. “Most of these are awarded to empanelled architects or agencies and then through tender taken up by contractors or construction agencies. In this process, the design element or the role of the architect is diminished,” she said.

Although a draft master plan for the city has been developed time and again, urban planners and researchers often lament that it lacks vision, and never sees fruition thanks to the involvement of many governing authorities in the city. Today, Kochi city has a corporation limit population of 677,381 within an area of 94.88 km2 and a total urban population of over 2.1 million within an area of 440 km2, making it the largest and the most populous metropolitan area in Kerala. It comprises one municipal city corporation, eight municipalities, and 117 village panchayats.

Kochi is known as the financial, commercial, and industrial capital of Kerala.  It has an extensive network of roads, railways, and waterways. The islands are connected to the mainland through overhead highways and railway bridges.  It is home to Cochin Port, the International Container Transhipment Terminal, several commercial enterprises, and industrial parks.

Waterlogging, silting water bodies and choked canals

“In Kochi, the main problem is waterlogging,” says Benjamin Pottas, a retired landscape architect and environmental planner.

Pottas is a specialist in mapping wetlands and has worked with the state government for over 40 years.

He explains how Kochi has an intricate network of canals and low-lying wetlands. “When we build roads over canals or construct over wetlands, we stem the natural flow of water – from stream to backwater to the sea. So as opposed to the conventional flood, Kochi experiences a lot of waterlogging, which often leads to a flood-like situation,” he told Mongabay-India.

The main canals in Kochi are navigable for small and medium vessels. The secondary canals served as natural drainage canals in the city for flood waters, but today they are in an advanced stage of deterioration through silting and waste dumping and fail to serve their purpose. The effects of inadequate drainage become visible and real with flooding and waterlogging of low-lying areas during the rainy season.

Who clears the debris?

Apart from pollution choking the canals and backwaters, debris from infrastructural construction projects causes major waterlogging, leading to flood-like situations. 

The area in Don Bosco Kadavu in Vaduthala, where the Periyar River meets the Vembanad lake, is one such example.

An overhead railway bridge was constructed by Cochin Port Trust in 2007-2011, connecting Vallarpadam International Container Terminal situated in the Vallarpadam island on Vembanad lake to Edappally, a commercial region in Kochi city. The project was assigned to Rail Vikas Nigam Limited (RVNL), a central government agency. RVNL hired a private infrastructure contractor, AFCONS Infrastructure Ltd., for the job. In August 2009, a group of fishers residing near Vaduthala backwaters filed a writ petition at the Kerala high court against Cochin Port Trust, RVNL, the private infrastructure contractor and others. They complained that in January 2008, a bund was constructed across the backwater using red earth. The bund was constructed to carry out the work of piling for the railway bridge and was supposed to be temporary.

In January 2009, the project was completed, but the bund remained. The fishers complained that the bund obstructed the water movement and their fishing activity. They said that it was hampering their means to livelihood. Ten years later, August 2018 witnessed high rainfall and high tide in the tidal influenced water bodies. The region witnessed the worst floods the area has ever seen, with far-reaching consequences. A group of residents, with Santhosh as their main representative, came together under the banner of the Social Welfare Action Alliance Society (SWAAS), demanding an inquiry and action into the reason for the flood.

The temporary bund was constructed to carry out the work of piling for the railway bridge. The fisherfolk complained that it obstructed the water's natural flow and their fishing activity.
The temporary bund was constructed to carry out the work of piling for the railway bridge. The fisherfolk complained that it obstructed the water’s natural flow and fishing activity. Photo by Supriya Vohra for Mongabay.

The Kerala Engineering Research Institution (KERI) carried out an inspection to understand the obstruction of the Periyar river near Vallarpadam bridge at Vaduthala. They discovered remnants of concrete piers and drainpipes deposited near the railway bridge piers. They also found that sediment had collected up to a distance of 1 km upstream and around 2 km downstream of the railway bridge. The deposition mainly consisted of clay and silt contents, unsuitable for construction or beach nourishment. Of the 19 gaps, only two were functional for country boats to pass through.

Their initial investigation report in August 2021 concluded that if the total width of 780m were desilted, it would increase the natural flow of the water in river Periyar.

On June 9, 2022, the High Court directed the water resources department to form a “high level committee” and conduct an “enquiry regarding the formation of bund in Vaduthala” and submit a report.

The question then arose as to who would remove the debris.

On August 12 this year, a committee formed on the behest of the high court conducted an inspection on the formation of the bund and confirmed that the bund was formed entirely because of the construction of the Vallarpadam Container Transhipment Terminal railway bridge.

“We have been pursuing this issue since 2020,” Santhosh told Mongabay-India. “The high court has now formed a high-level committee under the chairmanship of the irrigation minister. AFCONS and Railway Vikas Nigam Ltd are also a part of this committee,” he said.

Is there a long-term solution?

While governing authorities and corporations try to dodge the blame and work to remove debris, people wonder if Kochi will ever be ready to tackle the flood.

“The government’s failure in anticipating the floods is catastrophic. After the 2018 flood, a lot of mud has accumulated, and now the river’s water collecting ability has significantly reduced. The impact will be immense and will be felt over the next few years. Because of this mud accumulation, a small spell of rain will have a tremendous effect,” Santhosh warned.

Savita feels there is a need to change the way urban planning is done in Kochi.It requires a vision that leverages this aqueous land instead of fighting it. This is not merely restricted to desilting drains before the monsoon as this is like treating the symptom. There is a need to identify and mitigate what is causing this. The answer may lie further upstream, where poor waste management has created clogging. Furthermore, it implores the restoration and conservation of wetlands and floodplains, which act like sponges absorbing excess water as well as rainwater harvesting. This requires a multi-department coordinated effort potentially across districts,” she said.

Lukose is hopeful for Kerala as a whole. “This year, the state has brought out Risk Informed Planning Guidelines, and that will be the new norm,” he told Mongabay-India.

View of a canal in the city of Kochi in Kerala.
Kochi has an intricate network of canals and low-lying wetlands. The main canals are used by vessels to navigate, while the secondary canals act as a natural drainage for flood waters. Photo by Supriya Vohra for Mongabay.

The government orders, issued in July this year, provide guidelines that aim to support Local Self Governments across the State to prepare Risk Informed Master Plans (RIMPs) in a structured manner, with the objective of identifying factors that contribute to the vulnerability of exposed elements, propose techniques for risk assessment and mapping, and methodologies to integrate risk into land-use planning, among other risk reduction strategies. The question, however, remains – will this work for the busy city of Kochi that is governed by so many different authorities?


Banner image: As climate change makes weather patterns more and more erratic, it is important to understand factors that cause flooding at a localised level. Photo by Dilshad Roshan/Wikimedia Commons.

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