Drains of Chola era have formula to tackle floods

TIRUCHY: While the fury of Cyclone Michaung rained woes from all sides and of all kinds in Chennai and its neighbouring districts, the public faulted the stormwater drain network for the unprecedented problems.

On the contrary, the stormwater drains that were constructed by King Raja Raja Chola have been successfully serving the purpose even after 1,013 years. Buoyed by their efficacy, historians have suggested the State government consider adopting the methodology or the plan to handle such catastrophes in the future.

King Raja Raja Chola I era, which witnessed a series of rich cultural and artistic experiences ranging from literature to music and dance, was also rich and world-class in architectural knowledge. The great Chola King has left us several architectural marvels that can be effective even in the present day going by their unblemished track record.

One of the masterpieces of the Chola era is the ‘Thanjai Periya Kovil’ (The Big Temple), which boasts of carefully chiselled stone walls within the fortified complex, where names of all those involved in creating the edifice, have been carved setting a path for them to enter the history. To date, it is venerated across the globe.

Not just architecture, the Chola King possessed exemplary knowledge in water management with exceptional ideas. Testimonies of his acumen are in front of us even today. One classic example is the stormwater drain system made in the Big Temple, which is connected to the Sivagangai Kulam (Sivagangai tank).

To date, the structure stands firm and drains any quantum of water within minutes. Never in its history, the Big Temple has reported inundation.

Realising its worthiness, Maratha King Serfoji, who ruled Thanjavur thereafter, maintained the structure in its same form and intact.

“Raja Raja Chola was also keen on making optimum use of rainwater and keeping in line with this, he created more than 50 waterbodies, including several tanks and lakes, across the Chola Nadu (Chola empire) and made Thanjavur, the rice bowl of India,” said Mani Maran, historical researcher of Saraswathi Mahal, Thanjavur.

He further said that the King was also keen on providing potable drinking water by conserving rainwater and thus he constructed the Sivagangai tank near the Big Temple and made storm water drainage with the ‘Chalavam’ technique (shutter-like technique) with two layers of granite stones from the Big Temple and made two lines and linked them with the Sivagangai tank.

According to the technique adopted by the King, both lines were used for draining rainwater. The first rainwater would be released to Nandavanam as there would be silt and dust particles and the flow from the subsequent spells would be diverted into the Sivagangai tank after closing the Chalavam. As a result, the tank has good storage throughout the year. The excess water from the Sivagangai tank would be sent to other water bodies like Ayyankuklam and Samanthan Kulam.

“Through the proper stormwater drain lines, these waterbodies used to brim during most days of the year and they have been successfully catering to the needs of the people living around them even today,” Mani Maran said.

The same procedure was followed by the Maratha King Serfoji II with the concept of “Jala Soothiram” through which they created several wells and ponds on the Big Temple premises and connected them using pipelines to supply drinking water to the people.

The Maratha kings used limestone and clay for the drinking water pipelines, which are strong, and even giants like elephants could not damage them, Mani Maran said.

Thorana Vaical, the flood protector of Pudukai

To prevent flooding in Pudukkottai as most of the areas are low-lying, one may witness several wide open stormwater drains -- ‘Thorana Vaical’ that were constructed during the Thondaiman dynasty who ruled the erstwhile Pudukkottai State. These open drains still serve the purpose of protecting the residents from flooding.

Geographically, Pudukkottai has too many raised areas like Machuvadi and low-lying areas. The Thondaimans who ruled the then Pudukkottai had designed stormwater drains in such a way that the flowing water never hindered the day-to-day activities of the people.

This concept gave shape to the construction of ‘Thorana Vaical’ across Pudukkottai. Based on the geographical setup, these canals would flow from north to south of its land condition.

These canals are almost 15 to 20 feet wide and can take any quantum of water and are linked with the various tanks constructed by Thondaiman.

As a part of the annual desilt programme, the Pudukkottai district administration would never miss these ‘Thorana Vaicals’ as these canals play a pivotal role in reducing the risk of flooding.

But as usual, many canals were encroached on in due course of time and these stormwater drains lost their sheen and many became abandoned.

For instance, the ‘Thorana Vaical’ flowing in front of Kalaignar Karunanidhi Government Arts College for Women, Kalaignar Karunanidhi stadium, Thilagar Thidal, and new bus stand areas have been posing an environmental threat presently.

However, the civic body has been monitoring the canal periodically. “These canals play a major role in flood prevention across Pudukkottai but people litter the canals and waterbodies that chokes the free flow of water. But still, we keep on clearing the wastes before each monsoon,” said Liyagat Ali, Vice Chairman of Pudukkottai Municipality.

Recently, the civic administration cleared tonnes of garbage ahead of the monsoon.

“Each time, these canals (Thorana Vaical) rescue Pudukkottai, particularly the town areas from flooding.

They are designed in such a way that they can flow freely and reach the tanks created across the district.

The Thondaiman rulers have carefully made these canals mostly from north to south direction owing to the landscape,” said S Jayaprakash, an Archaeological enthusiast from Pudukkottai.

Smart City project helps revival of ancient waterbodies

While the ancient rulers left behind several good works, particularly waterbodies, for the people, the governments of the modern days have failed to make effective use of them.

As a result, many of them have vanished. But thanks to the Smart City programme, as it raises hopes that could revive a few of the water bodies that have been abandoned.

The Chola, Nayak, and Maratha kings have ruled the erstwhile Thanjavur and all of them accorded priority to water management by creating more than 50 waterbodies to support irrigation extensively.

The combined little fort and the big fort of Thanjavur were encircled by a moat, a trench filled with water to protect the structure from invasions. The water to the trench and the moat would come from Vadavar river due to natural gravity.

These moats around the Big Temple, Mela Alangam, Keezha Alangam and North Alangam and Sivagangai Kulam (tank), Samanthan Kulam, Ayyankulam, Azhagikulam, and Sevvappan Lake are the best examples of the water technology adopted by the Chola, Nayak and Maratha kings.

Apart from serving as rainwater harvesting systems, these man-made water bodies are recharged by the Vennaru, Vadavaru, and GA Canal.

However, in due course of time, several waterbodies in Thanjavur were encroached by private parties and these prevented the free flow besides posing a flooding threat to the region.

However, in the recent past, the civic administration has initiated steps for the revival of these waterbodies under the Smart City programme.

Initially, the civic body evicted encroachments and gave a fresh lease of life to waterbodies like Azhagi Kulam, Ayyan Vaical, Sevvappan lake, and Grand Anaicut.

“The revival of these ancient waterbodies would continue, and Thanjavur would become self-sufficient in water needs,” an official from the City Corporation expressed confidence.