What makes the Ahom architectural marvels in Assam still stand tall

There is a strange whiff of nostalgia about the Kolia Bhomora bridge in Assam – somewhat overwhelming, a whole lot mystifying. Connecting people divided by the mighty Brahmaputra, the 3-km-long concrete stretch beseechingly spreads out to join Tezpur (Sonitpur district) on the north bank with Kaliabor (Nagaon district) on the south bank.

Built nearly 35 years ago, the Kolia Bhomora has bridged many a gap between longing hearts on both sides of the bank separated by the braided river that sprawls out in front of the eyes until eternity. The concrete structure takes its name from Ahom General Kolia Bhomora Barphukan, who historians claim, was the first one to conceive an elaborate plan to construct a bridge to connect both the banks as early as the 16th century.

The Ahom General was the first to realise the need for a bridge on the location since he, along with his army, had to cross the river several times from the south to the north bank to crush rebellions within the Ahom kingdom and thwart attacks from the outside. For the uninitiated, the Ahom dynasty ruled Assam for nearly 600 years (1228–1826). Established by Sukaphaa, a Shan prince from Mong Mao (present-day China) who came to Assam after crossing the Patkai mountains, the rule of this dynasty ended with the annexation of the British East India Company following the Treaty of Yandabo in 1826.

According to historian Hiteshwar Barbaruah, there was a major rebellion in the early part of the 18 th century in the present-day north bank of the Ahom territory. As a result, Kolia Bhomora had to cross the river to defeat them, and in the next few years the Ahom army had to fight several external aggressions to the kingdom on the north bank.

He had identified the place for its strategic location and even got the approval to construct the bridge. However, the construction work couldn’t be completed.

“During that time, the Ahom kingdom had faced continuous challenges on the north bank of the Brahmaputra and General Kolia Bhomora Barphukan who was stationed at the south bank had to often cross the mighty river with his army. As a shrewd military strategist, he realised the need for a bridge connecting the north and south banks to facilitate quicker movement of the armed forces,” says Prof Jahnabi Gogoi, Department of History, Dibrugarh University.

“The brilliance of his strategic thinking is evident from the fact that centuries later with the help of modern engineering knowledge, the bridge [Kolia Bhomora] was built in 1987 on the same location identified by him,” adds Gogoi.

What’s more, nearly 35 years later, a second bridge running parallel to the Kolia Bhomora bridge is slated to be inaugurated by Prime Minister Narendra Modi. The newly constructed bridge across the Brahmaputra connecting Koliabor Tiniali and Tezpur has been temporarily opened for vehicular traffic recently with the old bridge now closed for repair works.

While General Kolia Bhomora died centuries ago, his legacy continues to live on. In fact, it’s not just the Kolia Bhomora bridge, the Ahom rulers have left behind many such examples across Assam that bear witness to their ingenuity and architectural brilliance.

Back to basics

Apart from a formidable military system, the Ahoms also developed advanced engineering techniques and built earthquake-resistant buildings during their reign. All those structures withstood several major earthquakes in the region, unlike many other buildings built with modern technology and architecture that were reduced to rubble.

According to the seismic zoning map of the country, Assam falls under Zone V, considered a “very high damage risk zone”. The state has witnessed several massive earthquakes, including the one in 1950 of 8.7 magnitude on the Richter scale. Also known as the great earthquake of Assam, it caused widespread devastation throughout the frontal regions of Northeast Himalaya. While such earthquakes caused huge damage to modern-day properties and buildings, the Ahom-era constructions remained mostly untouched.

According to archaeologists, the techniques and technologies used by the Ahoms to build their buildings were much advanced. They would make the immediate surroundings of the buildings earthquake-resistant by creating waterbodies nearby and using stone boulders underneath the structures.

“The Ahom kings tried to make the immediate environment of the structures earthquake-resistant, which is a unique feature of Ahom monuments,” says archeologist Milan Kumar Chauley, who has extensively researched on Ahom-era buildings.

The base platform of these monuments, he adds, rests on stone boulders, and beneath the boulders lies a thick layer of clay. The water from the tanks and ditches on both sides of the structure fills the gap between the boulders.

The foundations of these structures were made with sticky clay and the river boulders. The water tables in the water bodies around these structures were maintained at the level of the foundations of these structures so that they remain wet throughout the year.

Explaining the technique, Chauley says when an earthquake occurs, the intensity of its waves is diluted by the clay layers, boulders and water.

While studying one of the famous Ahom-era monuments, the Talatal Ghar, using ground-penetrating radar, archeologists found underground foundation walls that are extensions of the walls above and had separate walls built parallel to them. The space between these was packed with earth so they could bear the impact of earthquakes.

The Talatal Ghar, initially built as an army base, houses two secret tunnels and three underground floors that were used as exit routes. While these three underground floors are closed for tourists, the four above the ground are very popular among tourists.

The Ahom kings always ensured that the water level of the ponds was at a certain level so they could constantly fill up the gaps between the boulders.

“The water tanks and the ditches play a crucial role in making the monuments earthquake-resistant. If water is drained away from them or the water level is disturbed owing to human activities, it will lead to collapse of the monuments,” Chauley adds.

According to Ahom-era manuscripts, over 150 tanks were dug by the Ahom rulers in Sibsagar district alone to meet the religious, community and domestic needs of the then members of the society, and at the same time to check that these structures are earthquake-resistant.

Bridging the gap

Apart from buildings and monuments, the Ahoms also had an advanced system for travel and communication. One of the most important bridges built in that period was the Namdang Stone bridge (locally called Namdangor Xilor Xaku) which was cut out from a single piece of rock.

There are also references of as many as 10 stone bridges in the Ahom chronicles, also known as Ahom Buranji. The 60-metre-long Namdang Stone Bridge is one of them.

The bridge was built in the year 1703, and as per traditional wisdom a special paste of egg, rice and lentils was used in the construction process. Despite several major earthquakes, the bridge stands tall with hundreds of vehicles passing through it every day.

It is this ingenuity of Ahom architects that continues to catch modern-day engineers by surprise.

The Ahom architecture in Assam, archaeologists like Chauley say, reflects local heritage and elements. “They made the maximum use of their natural surroundings, flora and fauna, water elements, and the available materials to create architectural wonders.”