Wetland Fragmentation Caused by Rapid Urbanisation
by Lavenya Parthasarathy
The Pallikaranai Wetland is the last surviving wetland ecosystem in the city of Chennai. As Chennai accelerates towards urbanisation, the importance of the environment and natural resources is continuously neglected. In the last 50 years the Pallikaranai Wetland has shrunk to an alarming one tenth of its size, into a forgotten echo of a once biodiversity-rich, thriving habitat. The article explores the current role of the wetland in the built environment by analysing and unraveling the complexities that the wetland faces as the city expands. The tension between natural infrastructure and architecture holds potential to conceptualise these buffer zones, creating a large system of architectural landscape integration. The vision aims to reintegrate the wetland as a recognised layer within the urban fabric by initiating a harmonious relationship between human and nature, contributing to the enhancement of the ecological condition of the wetland habitats and creating liveable environments.
With more than 50% of the world’s population now living in cities, this progress towards urbanisation has transformed the urban landscape. Embedded within the heart of the multi-layered composition of a city is its network of green-blue infrastructure. Every city is characterised by a unique network of green-blue infrastructure which holds it together like an invisible glue. Historically, urban centres have been founded based on the natural availability of green-blue infrastructure, as it is key to basic survival. Early settlements have formed on the basis that there is fertile land and water bodies accessible nearby. As a city develops, the fundamental need for the green-blue network has been forgotten.
“Cities are a relatively recent phenomenon with a buried history. Not only are they built, ‘on top of earlier cities,’ but also many earlier cities were built on top of wetlands, such as London, Paris, St. Petersburg, Berlin, Chicago…”  Most cities have developed and evolved with wetlands at their heart. Wetlands provide easy access to water and rich agricultural land. Throughout history, proximity and approach to water have been key factors in human settlement. Wetlands play a critical role in providing freshwater, improving water quality, regulating climate, mitigating storm surges, supporting biodiversity and acting as a carbon sponge. Despite the ecological importance of wetlands, as cities transitioned from a largely natural landscape towards a more built-up setting, the original habitats that existed within these environments have since been squeezed out. In order to accommodate to the continuous urban sprawl of cities, many of these wetlands have been drained and built on entirely, leaving behind only degraded fragments. As is the case with many major cities, the role of wetlands within the landscape of Chennai has transformed dramatically.
Chennai, situated on the shores of the Bay of Bengal is the fourth largest metropolitan city in India. Chennai holds an extensive ecological history. The biodiversity of Chennai is said to have evolved from two cultural landscapes - the majority of which is ‘Neidhal’ and some ‘Pālai’ as classified in the Sangam literature. The landscape of ‘Neidhal’ represents the coast and is associated with coastal wetlands, whereas ‘Pālai’ refers to dry lands. With a coastline of 19km, Chennai is largely influenced by its coast and wetlands.
Historically, Chennai’s wetlands have had a crucial role in sustaining aquatic biodiversity and in flood mitigation. Over the years, as one of the major cities of a developing country, the city has continued to expand and spill outside of its original boundaries. This process has taken over more and more of these ecosystems that managed to survive on the periphery. The magnitude of this expansion may perhaps have caused irreversible, environmental damage. The rapid sprawl of Chennai has led to shrinkage of many water bodies and wetlands. The last few decades have been instrumental in the dramatic transformation of Chennai’s wetlands, many of these valuable wetlands have suffered degradation because of soil waste disposal and others have disappeared entirely because of infrastructure development. The expanse of wetlands within the city boundary has decreased from nearly 474 to only 5 major wetlands remaining.  Despite the fact that Chennai has witnessed the loss of many of these ecological treasures to ill-planned urban expansion, about 20 km south of the city’s centre Pallikaranai Wetland still manages to survive within the city’s extended limits. The narrative of Pallikaranai Wetland holds a deep, extensive struggle for its survival.
FRAGMENTATION OF PALLIKARANAI WETLAND
The Pallikaranai Wetland is the last surviving natural wetland ecosystem in the city of Chennai. The wetland has been a biodiversity-rich habitat, playing an integral role in the city’s natural infrastructure. Historically, the landscape character of southern Chennai is flood plain, with the large Pallikaranai Wetland and smaller wetland systems combined with tracts of pastureland and patches of dry forest. The Pallikaranai Wetland itself is a freshwater wetland spanning 80 sqkm, and it is the city’s natural primary aquifer recharge system.
The external alterations of the wetland system began in 1806 with the construction of the 422 km Buckingham Canal (less than 1km from the sea) as a salt-water navigation waterway.  The canal connects to the wetlands via a channel called the Okkiyanmadavu. This system has created a seasonal hydrology which sustains the wetland ecosystem. The freshwater drains into the sea during the monsoon and the seawater enriches the habitat during drier seasons. The addition of the Buckingham Canal has managed to sustain a stable wetland ecosystem. However, many other external changes made to the wetland have not been as beneficial. As the city continued to expand, Pallikaranai Wetland witnessed a total transformation to its surroundings. With more than 10 million inhabitants, the infrastructure of the city has not kept up with the expansion. Forcing more and more unplanned developments to be constructed around and on top of natural resources such as wetlands.
In 1965, the spread of the wetland was recorded at 5,500 hectares. Today, the area that Pallikaranai Wetland covers has reduced to only about 600 hectares. In the last 50 years, the wetland has shrunk to an alarming one tenth of its size. This endangerment is a consequence of complex issues that the natural asset faces due to rapid sprawl. Through the years, an accumulation of uncontrolled urbanisation and encroachments has led to the shrinking and silting of the wetlands. Various sites have been built very close to or on top of the wetland itself, shrinking the original boundary of the Pallikaranai Wetland. The construction of sites such as overpasses, educational institutions, hospitals, IT parks, shopping malls, railway lines and other insensitive developments have not only shrunk the wetland but have also affected the free flow of water within the wetland. Stifling vital natural water bodies and replacing them with building developments has led to a lack of flood management. The storage capacity of natural water bodies within the city is being reduced because of unregulated urban planning and illegal construction, leading to events of flooding. Without a robust flood management system or even rainwater runoff measures to counteract the newly developed infrastructure, recent monsoon months have led to large-scale flooding. During the 2015 South India floods, more than 500 people were killed and nearly two million people displaced. When analysing the causes of the flood, the widely accepted conclusion has been unregulated planning and illegal construction, improper design and maintenance of drainage systems. Even after going through such devastating flooding in 2015, the city has seemingly not learned from the past, as the set of floods that have occurred in the following years have also inflicted significant damage. As we move towards urbanisation we only see land for buildings and the green and blue infrastructure becomes invisible.
One of the major threats to Pallikaranai Wetland is the dumping of waste. Professor Dr. Kurian Joseph from the Centre for Environmental Studies, Anna University shares, “Because of the lack of awareness about the ecoservices of wetlands, people start dumping waste there and wetlands become wastelands. After several years, the wastelands get converted into construction sites and we face scenarios like flooding. With improved waste separation at source and better waste management, we can stop the wetlands from being polluted with garbage”. 
Astonishingly, one of Chennai’s largest official dump sites is also located within the boundary of Pallikaranai Wetland. In the mid-1980s, the wetland started being used as a landfill site. The delicate wetland ecosystem is contaminated with nearly 2,000 tonnes of waste daily. The pollution and contamination caused by continuous expansion of a landfill site located within the wetland itself has highly degraded the quality of the habitat, possibly leading to unknown long-term consequences. The overall negligence has shaped Pallikaranai Wetland into a forgotten echo of what was a once thriving habitat.
THE KEY TO URBAN RESILIENCE
“In the not too distant past, wetlands were regarded as wastelands. Most people felt that they were places to be avoided, and it was common practice to drain them, fill them or treat them as dumping grounds.”  Unfortunately, this is still the case for Pallikaranai Wetland. The importance of wetlands is usually magnified by their absence in urban areas and Chennai has been naturally blessed with this treasure trove. Despite the fragmentation and stilting that the wetland has gone through, rare species of wildlife find refuge in Pallikaranai Wetland, some of which include glossy ibis, grey-headed lapwings and pheasant-tailed jacana. It is a sanctuary for wildlife within the boundaries of a city.
“The sky is a beautiful lilac-orange and its reflection on the water, vivid and faithful. A flock of spot-billed pelicans takes an elegant buoyant flight, criss-crossing the scenery. The sound of the curious common kingfisher is heard. The fulvous whistling duck ambles around looking for food. There’s fresh greenery all around.” 
Pallikaranai Wetland is a treasury of bio-diversilty, almost four times that of Vedanthangal bird sanctuary where more than 40,000 migratory birds, including 26 rare species, from various parts of the world visit every year. Care Earth Trust states the following about Pallikaranai, “The marsh has a recorded 167 species of birds, 100 species of fish, 141 species of plants (including 29 species of native grasses). The area acts like a sponge soaking up water during peak rainfall and releases it slowly during dry spells. The Pallikaranai marsh also plays an important role in groundwater recharge”.  The terrain of the Pallikaranai Wetland is composed of several landscape characters including fresh and saline water bodies, reed beds, mud flats and floating vegetation. The wetland acts as a forage and breeding ground for a wide range of wildlife, including birds, amphibians and insects, many of which are rare or endangered and threatened species. It is a refuge to many species of flora and fauna that have been exterminated from other parts of the city.
Wetland ecosystems play a crucial role in achieving a more resilient and sustainable city development. As these systems are reduced, the cities that depend on these environments have become progressively vulnerable to extreme climate change, and have been confronted by threats such as water shortage, urban heat waves, land subsidence and drought.  Urban wetlands make cities liveable - they filter and improve water quality, buffer the impact of floods and storm surges, act as a carbon sponge and improve air quality, subside heat islands, replenish groundwater, create spaces for recreation and education, offer biodiverse habitats and provide livelihood opportunities. As urbanisation continues at an exponential rate, re-integrating these essential ecosystems as climate buffers will allow many benefits. They will act as a natural hazard protection, help with flood mitigation, climate change adaptation, water management, encourage community engagement, be valuable for biodiversity and support fisheries.
In terms of efforts towards conservation, Pallikaranai Wetland is one of 94 identified wetlands in India under the National Wetland Conservation and Management Programme (NWCMP) and has recently been added to the RAMSAR list of protected sites.
In late 2021, a 2.5 acre ‘ecological park’ within Pallikaranai Wetland opened at the cost of £2 million. The ‘eco park’ contains a 2km walking trail, public green spaces and bird watching towers. Although this might be a step towards the right direction and to an extent tries to help educate the public on the importance of wetlands, the park has been criticised for ‘greenwashing’  - with its grand entrance, paved pathways, a water fountain, out-of-place native trees, a compound wall containing the wetland, and overall insensitive interventions. Rather than acting as wetland restoration, the creation of this £2m eco park has transfigured the wetland into a park for human recreation.
REINTEGRATING WETLANDS WITHIN THE URBAN FABRIC
Recently, the prospect of creating wetlands in and around cities has been given more recognition, following the disappearance of large stretches of wetland in recent decades. Wetlands are being designed as natural buffers for cities. While these large movements toward creating urban wetlands are credible, restoring surviving wetlands is more critical than ever. Wetland restoration involves taking efforts to restore a degraded wetland’s physical, chemical, or biological characteristics to return its natural functions. The restoration of wetlands creates livable environments. Architecture is defined by its natural environment. The tension between natural infrastructure and architecture holds the potential to conceptualise these buffer zones, the integration of context to create a large system of architectural landscape integration. This delicate balance has been successfully achieved in a number of urban wetlands around the world. Some key precedents include WWT London Wetland Centre, Yanweizhou Park in China and Mucking Marshes Nature Park in South Essex as precedent of a reclaimed landfill site.
The vision portrays the reclamation of the Pallikaranai Wetland, envisioning a transformation for the site by sensitively reintegrating the wetland into the urban fabric, enhancing the ecological condition of the wetland habitats. Promotes the wetland as a natural space within the city where the local community can gain access to nature, learn about and respect the diversity of plant and wildlife. Although restoration of wetlands takes a lot of effort and complete restoration may not always be possible, nature has the potential to repair itself. The vision reintegrates Pallikaranai Wetland as a recognised layer in the urban landscape by initiating a harmonious relationship between human and nature.
[Image 2] Five Sangam landscape classifications: Kurinji (Mountainous), Mullai (Forests), Marutham (Cropland), Neithal (Seashore) and Pālai (Dry Lands); romanticised in the Sangam literature showcases the cultural importance of natural landscapes.
Image by the author (2022)
[Image 1] Satellite View of Pallikaranai Wetland, Chennai.
Image by the author (2022)
 Giblett (2016)
[Image 3] Fragmentation of Pallikaranai Wetland; Hyperbolic portrayal of the urban sprawl of Chennai consuming the last surviving natural wetland of the city. Image by the author (2022)
[Image 4] Study of the tranformation of the Pallikaranai Wetland over the last 20 years, from 2002 to 2022. Image by the author (2022)
[Image 5, 6] Site Photo of Pallikaranai Wetland. Images by Sushmitha Shankar (2022)
[Image 7] Illustrative representation of the Blue Tailed Bee Eater, one of many unique species which calls the Wetland its home. Image by the author (2022)
[Image 9] ‘Vision for Pallikaranai Wetland’; represents the reclamation of Pallikaranai Wetland by re-integrating the wetland within the current urban fabric. Image by the author (2022)
[Image 8] Highlighted green and blue infrastructure of the Pallikaranai Wetland, with the encroachment of newly built developments in the background. Image by the author (2022)
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Published in Issue 2022
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