Rockslide would have Stopped there if it wasn’t Met with Large Quantities of Water - Interview with Hydrologist

“I am sure that the casualties of this natural disaster were mainly caused by people not knowing where to escape, and they may have fled toward the path of the mudslide, which is a fundamental mistake. When something like this is happening, people should know to find elevated, solid ground, and they might survive.

10 minutes would have been more than enough to avoid human deaths.

- Nika, the Minister of Environmental Protection and Agriculture, and the National Environmental Agency specialists before him, said that Buba River and its valley were not considered dangerous. You have published satellite images of Buba Valley from the years 2005, 2018, and 2020, which show a worsening trend. Should the National Environmental Agency have started monitoring the Buba Valley, at least after the mudslide of 2017 in the same valley?

- The satellite image of 2005 testifies that the river was less prone to flooding, evidenced by trees growing from the riverbed, they are newly grown, but they’re there, which means that the maximum water current hasn’t passed for a while. In 2018, the river channel is completely stripped, the bottom is visible, and the signs of mudslide passage are apparent. In 2020, the situation has worsened further, which signals that some geodynamic processes have been activated here.

Even based on just the satellite photos, they should have started monitoring the river, because the progression of alluvial processes is evident.

Also, Racha is widely known to be a flood-prone region. That’s why they had to carry out all these measures. Not just the National Environmental Agency, but other concerned parties, first of foremost, the municipality, which was responsible for the development of this region. They should have defined the risk zones.

- At the briefing held on August 9, where the media and specialists were invited selectively, [Mountain Stories was not notified, so we couldn’t question the decision-makers] First Deputy Minister of Environmental Protection Nino Tandilashvili said that “about half a million m³ of rocky mass, which spanned across 1.5 hectares, broke off from Bubastskali Valley, entrained 62 hectares of icy mass, and hurtled through the entire valley at a very high speed.

- A large quantity of water is needed for such cataclysmic processes to unfold.

Only a collapsed glacier or part thereof, a rockfall or glacial rockslide, is not enough to set all this content into motion. That rockslide would have stopped where it landed if it wasn’t met with a large quantity of water. So, this is the primary question that came to my mind and I could not find an answer in the report of the National Environmental Agency.

As they themselves say, 5 million m³ of mass was set in motion. At least 1 million m³ of liquid water is needed to trigger this amount of inert mass.

- At yesterday's briefing, the deputy minister reiterated once again that “before the disaster, there was no waterlogging, no build-up of water content,” however, he added that “calculations made by specialists showed the activation of subglacial lakes, which are not visible on the surface, which eventually caused the large-scale mudslide.” So, if we are to believe the deputy minister, in normal circumstances, without at least a few days of damming, so much water could have accumulated inside the glacier that it ripped off and carried trees, boulders, rocks, and everything in its path in the 3 km long, not-so-narrow valley of the river?

- Simply put, no. All of this needs to be substantiated by the National Environmental Agency, why they think that the water accumulated in a liquid state below the glacier without affecting the water level in the river. To prove this, they should publish the evidence they based this conclusion on.

- Is it impossible for so much water to accumulate below the glacier? What sort of proof are you asking from the National Environmental Agency?

- The zone of discharge of the glacier from the mass of liquid water, so to speak, is the bottom of the glacier tongue - the water comes out from the base. There might be some small lakes, but they would be in the core, so deep that they could not have been released by some mechanical forces on the surface.

- Is it possible that the rock avalanche, the collapse of which the Agency and the Ministry so stubbornly maintain, clogged the glacier tongue, which led to the damming of water for several days, which eventually broke out and carried everything?

- No, there is no evidence for damming.

They are not addressing the main question of how did so much water accumulate there without significantly affecting the water level in the river.

I agree with the National Environmental Agency that there was water. This mass would not set off without water, but they have to explain where this water accumulated. A glacier doesn’t melt at once, it takes time, 62 hectares of glacier is not going to melt in 5 minutes. This is absurd. Water is the agent that set all of this in motion. The conditions were already staged, the rockfall was just a trigger that set things off.

The notion that the abrupt collapse of part of the rock caused this is incorrect. One of the main agents in a landslide is water, large quantities of it. Especially when we’re talking about a structural landslide.

A turbulent mudflow is a type of mudflow where a large flow of water sweeps material along its path. For example, the 2017 event was a classic turbulent mudflow that swept everything in its path. In this case, it was a transition between structural and turbulent, because the innumerable mass was brought down, mostly broken mass, sand, mud-like content.

The volumes of content are very different. How did they calculate that the collapsed rockslide was 0,5 million m3? Did they eyeball it? They have not presented the justification and the data they are basing their conclusions on.

- In other words, the National Environmental Agency is offering us a conclusion, but we do not know what data and methodology it is based on.

- Yes, they are not publicizing anything based on which they came to that conclusion. Whatever happened over those 1.5 hectares, it could not have moved a mass spread over an area of 62 hectares if there was no underlying water there.

They themselves say that there were subglacial lakes. How did those lakes appear if water did not collect there?!

They do not say what the prevalence of Buba River water is in the Chanchakhi River. Is it 10%, 20%, or maybe 50%? If we look at satellite images, there are more glaciers in the Bubistskali Valley than in Chanchakhi itself, and therefore, in the absence of rain or other hydrometeorological factors, only under the conditions of the melting of the glacier it may turn out that more water flows into the Bubistskali valley than in Chanchakhi. The water level data can also be seen from the hydrograph of the National Environmental Agency, which they included in their report in the form of a graph.

The graph shows that the minimum water level for the last 2 months was recorded on July 31. The water level dropped drastically between July 13-16, despite intermittent rains, and this raises doubts as to why such a thing happened.

In the period of July 16-19, the water level dropped further. Therefore, they should check how well the water level gauge worked. If it was working correctly, then what caused the water level in the river not to rise at a particular date despite the rain, what is the explanation for this?

According to the graph of the National Environmental Agency, the temperature has significantly increased and the glaciers are intensively melting. In the same period, approximately 10-15 millimeters of precipitation was recorded, which for some reason is not reflected on the hydrograph. There is a very small increase, and the next day there is a radical drop in the flow of the river, which raises doubt. Maybe something happened on the glacier that stopped the flow out of the glacier and the incoming atmospheric precipitation compensated for it. Consequently, the peak was not what it should have been.

They should present last year’s data from the same gauge for comparison.

Glacial rivers release the largest amount of water when they are melting. The melting peak in the Caucasus is July, August, and the first half of September.

What happened is not a quick, instantaneous event, it develops over time. All kinds of natural disasters have a preceding chain of events.

- The government declares that it is practically impossible to predict a disaster of this scale in advance, and we could not have avoided the tragedy. The Speaker of the Parliament, the Leader of the Parliamentary Majority, and other public figures attack us, Mountain Stories, Green Alternative, and Seismic Monitoring Center, with unsubstantiated and irresponsible statements, for asking questions about the Shovi tragedy. Nika, was this foreseeable?

- When they keep saying that this was impossible to predict, this is essentially wrong. A short-term forecast would be possible if we had already made a long-term one.

What type of prediction is impossible? Long-term one is definitely possible, in any place. A short-term forecast would be possible if we had already made a long-term one. Long-term forecasting gives us many opportunities for prevention. Among them, in terms of emergency assistance, the arrangement of appropriate evacuation sites in such areas, so that people know where to go, and where to save themselves, in case of a natural process, so that there is no confusion.

When they say that it is impossible to predict and emphasize that the communists rerouted the riverbed and today the river has reestablished its route, it seems that they knew this before, and should have been prepared in advance.

One of the important parts of the early warning system is expeditionary research. There should be special teams that check the glaciers, if not monthly, then during the summer, especially between July and August at least. The ice sheet is most vulnerable during this period, that’s when it is melting, and there is intense pressure on it. Therefore, the first stage of forecasting is a long-term forecast. The National Environmental Agency has experience in this. In 2015-2016, they prepared similar risk zones and flood areas in the Kakheti region, on several rivers, and especially on Kvareli, Duruj because it is a tidal river. Various types of informational signs are still posted in public places in Kvareli, which indicate to people where they can take shelter and where there is a higher chance of survival. Something like this should have been done in Shovi, on the very first day when it was decided to redevelop this resort, especially if they knew that the communists had changed the riverbed. They made all the wrong decisions from the very start and this place was dangerous.

When the National Environmental Agency did similar modeling on the rivers of Kakheti, as far as I remember, we had grant support from the Polish Embassy. After its completion, I don't know why similar modeling was not continued in other naturally active river valleys. Were those trainings conducted in vain? We are not talking about big rivers, which are being built within the framework of the Green Climate Fund grant. It is necessary to do the same on small rivers because processes develop faster here. If a similar event would take an hour on the Rioni River, it was a matter of minutes in the case of the small River. Therefore, when there are such forecasts, the first to get attention should be small rivers that pass through populated areas.