Chennai faces severe flooding, with 42% of its coastline at risk of erosion. The Neithal Trail’s scenic boardwalks and viewing decks are designed to educate, inspire sustainability, and encourage conservation efforts among locals and tourists alike.
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00:00This group is on a special kind of city tour.
00:04As local residents, they want to know why Chennai keeps flooding.
00:08Right away, they learn a bitter truth.
00:12Decisions on building and infrastructure mean the Pallikaranai marshland,
00:16a natural wetland, can no longer absorb as much rainwater.
00:20So now, we may think that we are riding or driving on the road,
00:26but we are just driving on the marsh, actually.
00:31This has been fragmented.
00:33You can see on either side of the road, you can see the marsh.
00:38This connectivity has been lost.
00:41On the right-hand side, you can see the marsh,
00:44which gets connected to the Buckingham Canal and then to the Bay of Bengal.
00:52This was Chennai in December 2023.
00:55The Tamil Nadu capital floods regularly when the annual northeast monsoon
01:00brings the heaviest rains.
01:02And climate change is making the rainfall more extreme than it used to be.
01:09For city dwellers like Bhuvana and Rajalangov,
01:12the reality of the climate crisis is now literally at their doorstep.
01:17We booked a house in a community close to Old Maliburam Road,
01:21IT Corridor, back in 2015, just a few months before the great Chennai floods.
01:26We thought of keeping the booking because we felt that whatever flooding happened,
01:32it happened only once in a lifetime event.
01:34It's not going to happen again.
01:35But having moved to the community the last seven years,
01:38we are getting impacted every monsoon.
01:40That is kind of creating a big issue for us.
01:44And our lifetime investment is getting impacted.
01:46We are feeling quite anxiety every monsoon.
01:51After one devastating flood, Raj heard about Heritage Inspired,
01:55a touring firm that explores cultural history.
01:58The recurring floods prompted them to focus on the city's natural heritage
02:03to help locals gain a better understanding of its coastal ecosystem.
02:0715-20 years back, we had good monsoons,
02:10but we didn't have problems like flooding back then.
02:13So, as citizens, we wonder what has changed from then till now.
02:17So, at HI, we wanted to address these concerns in the form of a tour
02:22by taking experts along with us and getting these questions clarified through experts.
02:28Basically, this would involve understanding about our ecosystem,
02:31how it functions, what has changed now.
02:33So, all of this will be covered on this tour.
02:36The company has taken thousands of students and working professionals on weekend trails
02:41looking at Chennai's fragile coastal ecosystems.
02:45The name of the trail, Neithal,
02:48refers to the coastal landscape as described in literature from the Sangam era,
02:53a Tamil poetic tradition dating back 2000 years.
02:58The Pallikaranai Marsh is often called the Kidney of Chennai.
03:02In the past, it could absorb excess water from interconnected reservoirs
03:07across more than four districts around Chennai
03:11and gradually channel it into the Bay of Bengal.
03:17But now, since it is less than 10 percent,
03:20the spread of water has increased.
03:23Now, since it is less than 10 percent,
03:26the sponge nature of the habitat has reduced drastically
03:32and that's why we are facing a lot of inundation.
03:36So, it's not flood.
03:38This is what it looks like if we work with nature to reduce floods.
03:43Tamil Nadu's first sponge park was created by consultant urban designer Manushi Jain and her team.
03:52It's in Purur, a western suburb of Chennai, around 20 kilometers from the city center.
03:57So, two years ago when we first arrived on the site,
04:00it was completely asphalted and it was used as a car parking lot.
04:04There was a water body here which was completely eutrophied.
04:07This particular site is a remnant of a wetland
04:10and there was a significant opportunity here to revive this back
04:14and showcase this as a demonstration of how wetlands can be very critical infrastructures
04:20and we tried to make sure that this site could behave like a large sponge
04:24where we kind of created more room for water within the park.
04:28The design slows water movement across the land,
04:31reducing the risk of flooding during monsoons.
04:34Small, carefully shaped mounds increase the area's ability to hold water,
04:39so rainfall is better managed.
04:41Excess water is absorbed into the ground.
04:45And last monsoon, what we saw was this whole area flooded with water
04:49but it was done in such a way that the water level never breached the boardwalk level.
04:53So, we've graded it so that the water can kind of delay and slowly infiltrate into the ground
04:58and the excess water then moves towards the lake.
05:01Therefore, we're reducing the flooding
05:03and ensuring that the lake is not getting overwhelmed during the monsoon.
05:07The Buckingham Canal could also absorb more rainfall during the monsoon.
05:12It's another stop on the tour.
05:14But silt and invasive water hyacinths are blocking the former trade route
05:19built by the British in colonial times.
05:21Today, it's only about 30 centimetres deep.
05:24But in principle, it could absorb large quantities of water
05:28and channel it into the Bay of Bengal.
05:33If we start desilting and widening this Buckingham Canal,
05:39this can be like an express highway.
05:43This will be the express waterways
05:46where it can drain water at a very short period
05:52when we are facing a cloudburst and a very downpour within a short duration.
05:59The Nethal tour ends with some practical tips.
06:02Bhuvan Araj shows the group how to separate household waste correctly
06:07so that it doesn't end up clogging waterways.
06:10Equipping citizens with information
06:13so they can help protect Chennai's valuable wetlands for the future.