Cyclone Fengal hits Auroville

In Tamil Nadu, Cyclone Fengal wrought havoc in 14 districts, delivering the equivalent of a monsoon season’s rainfall in just 36 hours. Certain areas received around 56 cm of rain. Crops were flooded, lakes breached their banks, dams broke, trees were uprooted, livestock drowned, civic infrastructure was damaged, and thousands of people were displaced. The Villupuram and Tiruvannamalai districts received more than 51 cm of rain in a single day.

The cyclone also brought extremely heavy rainfall to Puducherry, with the Union Territory recording 48.4 cm of rain over 24 hours, as of 8.30 am on December 1. This marked the highest 24-hour cumulative rainfall in the last 30 years, news agency ANI reported. On 2 December, Puducherry was hit with another disaster when water was discharged from the brimming dams of Tamil Nadu, particularly the Sathanur dam in Tiruvannamalai. Flood-like situations resulted: arterial roads were submerged, basements and ground floors were inundated, and four residential areas waterlogged for more than a week.

Auroville

The cyclone also wrought havoc in Auroville, where a weather logger reported that 54 cm of rain had fallen in 24 hours, an all-time record for the community. Hundreds of trees were uprooted, roads were blocked, and the ground floors of Bharat Nivas and of some apartments were flooded. There was a general power outage, which was gradually restored, but in some communities only after two weeks. Internet connections too were disrupted. A few Auroville communities suffered water shortage. The damage caused to houses and storerooms, however, was less than that sustained during Cyclone Thane.

But the situation at the Matrimandir Lake was different. In the Matrimandir Newsletter, published in the third week of November, executives had announced that the Matrimandir Lake section 1 (also known as the Test Lake) was ready for the monsoon as the concrete block walls (also known as Lego block walls) at each end of the 100 metre long Lake section 1 had been raised to their full height of 10.6 metre. “Once the expected good rains of the upcoming winter monsoon arrive, harvested rain water, flowing from the Gardens into the open water channel, will pour into the Lake, raising it up to its full level … And then finally, after only three years of collecting the rainwater, we will all get a first view of the Lake as envisaged by the Mother,” they wrote.

It was not to be. At some time during the night of the cyclone − a few minutes before midnight according to a surveillance camera − the Lego block wall that separates Lake section 1 from the as yet unfinished and unlined Lake section 2, slid from its foundation into Lake section 2. It broke in the middle and at both banks, and water stored in section 1 cascaded into the 10m deep excavation of Lake section 2. The situation was exacerbated when the water in the open water channel around the Matrimandir area also drained into Lake section 2.

On December 4, concerned Aurovilians wrote to the Matrimandir Executives and the members of the Lake Team, raising questions about engineering accountability and the use of donor contributions. They also recalled that over the past few years, they had requested that the executives obtain proper building permission from the community, get environmental impact assessments for the lake excavation and the mountain, pause tree-cutting and excavation, and consider integrating an alternate lake proposal that addresses ecological and aesthetic values [see AVToday November 2023, #412 and May 2024, #418], concerns that have been largely ignored or rejected. “The work continued in a hasty manner by setting an unrealistic time frame of completion [completing the Lake by The Mother’s 150th Birth Anniversary, February 21, 2028, see AVToday October 2023, # 411, page 5, eds]. This neglect highlights a significant failure: the disregard for participatory and collaborative processes, which are fundamental for the work on Auroville’s core values. We consider this to be the biggest failure in this project and yet to be acknowledged by the present Matrimandir executives and the Lake Team.” The concerned Aurovilians called for an entire reassessment of the project and for all involved to step back from the current course.

The Matrimandir executives and the Lake Team issued an extensive technical report on December 5, sharing the structural calculations for the Lego block wall, the details of its construction, and showing that the wall had been built with an additional reserve of about 30% over and above the recommended strength. The report stated that the sliding and opening of the Lego block wall was the result of a combination of four unexpected events, each of which was analysed. “They happened all at the same time during the cyclone, which discharged 60 cm of rainfall in one day. None of the four events alone would have been able to cause any damage. Even if two of the events would have happened simultaneously, it would have still been all right. But all four together had an effect where each one enforced the impact of the other three, which finally led to the sliding of the wall,” they wrote in the report.

The breaking of the wall has not discouraged the Executives nor the Lake Team members, who circulated an encouragement of The Mother: “Do not be sad – things happen because they have to happen and finally everything leads to the ultimate victory of the Supreme.” They stated that a different type of foundation, which will prevent a shifting of the wall, will be designed and that, most likely, there won’t be any financial disadvantage. But the wall between section 1 and 2 will not be rebuilt. Once the rains have stopped, the Lego blocks from the broken wall will be removed. As only a few blocks got damaged, all the others will be used to build the next wall, 180 metres away, at the end of section 2, so that section 1 and section 2 of the Lake will be joined. “This means that it will not be necessary to manufacture new Lego blocks for the third wall, which was the plan till now. This is a big saving. So in total, the new concept is less expensive than the plan which we had so far,” wrote the Executives. They expressed the hope that the rupture will not affect the proposed timeline, i.e. having the Matrimandir Lake completed by The Mother’s 150th Birth Anniversary on February 21, 2028.

The report has not satisfied the concerned Aurovilians. They wrote in another mass bulletin that the report highlights a significant lack of safety awareness in the planning and execution of the lake project and reflects a clear lack of accountability. They called for an independent third-party assessment to evaluate the failure of the wall design and engineering.

The report was also rejected by Aurovilian Jan Imhoff, who was the chief engineer of the project till the summer of 2023 when he resigned because of a difference of views with the Lake Team. At that time, the dams were 8 metres high and the water level in section 1 stood at 5 metres. In a detailed technical rebuttal he argues that the claim of 30% safety margin was not valid as the supporting earth buttress on the back side of the dam had been prematurely removed against the instructions in the technical specifications; section 1 of the Lake had not been provided with an overflow to ensure that the water does not rise beyond 10 metres, and the Test Lake was allowed to overfill; and the overflow weir of the water channel around the Matrimandir had not been lowered during the heavy rains to allow excess water to flow out. Consequently, there was a sudden inflow of water in Lake section 2 and the dam was flooded from behind. “These all led to the point where all safety margins in the design of the dam were used up and the dam failed,” he wrote.

Jan also claims that there had been carelessness by not considering the impact of the heavy cyclonic rains. “It has already been raining heavily for hours and a large amount of water is collecting in the Test Lake and the next section of the lake [Lake section 2, eds.]. The Test Lake is full and the channel around Matrimandir is overflowing onto the oval road. All sump pumps from the Amphitheatre and under the Matrimandir are working overtime pumping even more water into the channel and that flows into the Test Lake. Nobody stops to think – what will happen now that the Test Lake is full, where will all the water go? Instead, everybody just went home.” He expressed the hope that the failure of the dam will be a chance to improve the lake design, and change the way it is executed and impacts the people of Auroville.