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Federal Research Center 
"Krasnoyarsk Science Center of the Siberian
Branch of the Russian Academy of Sciences"

 Федеральный исследовательский центр «Красноярский научный центр Сибирского отделения Российской академии наук»

Federal Research Center 
"Krasnoyarsk Science Center of the Siberian
Branch of the Russian Academy of Sciences"

Why does the Abakan channel bloom?

26 February 2021 г.

Почему цветет Абаканская протока?
Journalists of the newspaper “Gorodskiye Novosti” had a talk with the scientists of the Institute of Biophysics SB RAS about the research being conducted on the Abakan channel.

Persistent greens

The struggle for clean water in the Abakan channel has been going on for many years: the reservoir is overgrown with algae, which are mowed, but the next year everything starts again. From the point of view of the layman, everything is obvious: the channel is blocked by a dam, and there is a drainage pipeline which, apparently, cannot cope with its task. Added to this is the intensive economic activity, namely, a new residential area has been built here, there is a fish farming enterprise, and the water itself is warmer than in the main channel of the Yenisei due to the proximity to the Combined heat and power plant. Warmth, minimal current, a large amount of organic matter from the banks result in the water blooming. Unfortunately, getting rid of this vegetation is becoming not so easy.

The blooming water spoils the aesthetics of the city, some people even believe that plants can pose a threat to human health and affect the quality of life of river fauna.

In general, the causes of the environmental problem are obvious, but we still need to consider all possible solutions. It is impossible to simply demolish the dam as the city needs it, while it is also impossible to remove artificial embankments and enterprises from the channel banks. Thus, it is necessary to look for a balanced way out.

The water in the channel is of the lake type

In 2019–2020, experts from the Institute of Biophysics studied plants in the Abakan Channel. They studied the physical and chemical characteristics of the water, measured the flow rate, took samples of living organisms in different parts of the reservoir in order to find out what mostly affects its blooming.

For observations, scientists chose several sites. One of them, located in front of the dam, was used to obtain data to serve as background values taken in an undisturbed part of the river.

The other sites were located a little downstream: in the area where the heated waters of the CHPP enter the channel, down the fish cages, and near the city beach. Firstly, the scientists found out that the water in the Abakan channel is now mostly of the lake type, leading to a change in the species composition. There are now many crustaceans and algae, which are typical of lakes. Macrophytes are also intensively growing in stagnant warm water. It is their dominance that the scientists are fighting against.

“The first thing that the city authorities have begun to do is reducing the number of macrophytes. But this is not enough,” says Alexander Tolomeev, Candidate of Biological Sciences, senior researcher. “Macrophytes also play a positive role, as they contribute to water purification. It is worse when they are absent at all, in their place cyanobacteria appear and they can be toxic and kill fish."

The problem is not created by macrophytes themselves, but by their dead biomass. Usually in the river it is carried away by the current, which is absent in the Abakan channel. Macrophytes retain debris and become debris themselves with time. They rot, and as a result, the water stagnates, changing its color, and there appears a smell.

Similar to lake Baikal

Small algae living at the bottom are also safe in themselves. This is spirogyra, a filamentous alga similar to green cotton wool.

“Spirogyra grows on stones at the bottom,” says Elena Kravchuk, Candidate of Biological Sciences, senior researcher. “But under certain conditions, Spirogyra starts intensively growing, its mass increases, algae break away from stones, and float to the surface. Due to the lack of water movement, they become entangled in other plants, entwine them, and rot"

However, on lake Baikal the population of unique sponges filtering water suffers from Spirogyra. But in the Abakan channel, the situation is still only an aesthetic problem, and it hardly affects the fauna.

“Spirogyra itself is not harmful for people,” continues Elena Kravchuk. “But due to its decay, other bacteria develop, and the quality of water deteriorates, which can have a negative effect on people.”

For people, swimming in reservoirs with a large amount of Spirogyra can result in allergies and light food poisoning, irritation of the skin and mucous membranes. It is better to not to deal with such water. By the way, bottom algae is one of the reasons why the beach on Tatyshev Island, which is beloved by many Krasnoyarsk residents, is now a forbidden place for swimming. Spirogyra is removed from the channel along with macrophytes when the reservoir is cleaned. And this is the most obvious solution to the problem, but not the most effective and economical.

“The state of the reservoir is not yet deplorable, it just does not fit into the aesthetics of the Yenisei” says Alexander Tolomeev. “The main thing is not to leave everything as it is. Vegetation decays, and if its volume becomes too large, it can really become an actual problem".

New inputs

Scientists are not yet ready to make final conclusions nor to provide recommendations to the city. They collected data, measured the parameters of the system, and all the options are being evaluated as to the development of events. However, we cannot just sit and wait. Therefore, in Krasnoyarsk, a large campaign was organized last year to clean up the reservoir. In addition to usual measures, the embankments were also removed and drainage pipes were cleaned, so that the reservoir relief changed, which would affect the situation with the flow rate. This summer, biologists want to further collect the data and, together with mathematicians, calculate new models for the development of events. In general, there is hope that in some near future the channel will be completely cleaned and it will be possible, like decades ago, to swim there in summer without allergies, poisoning or skin irritations.

"We must create a mathematical model of the ecosystem, show in which direction to move in order to save money and improve the situation," says Alexander Tolomeev.

Last summer, by order of the Ministry of Natural Resources and Environment a Krasnoyarsk specialized transport company worked on the Abakan Channel. Its employees cleaned the banks, removed the embankments and mowed aquatic vegetation. After all the work was completed, the channel returned to its original appearance. The plan for this large-scale order was coordinated ... with the spawning period of fish in the Yenisei, so as not to harm it.

Other enterprises which conduct their economic activities on the Abakan channel also took part in the implementation of the project, including the repair performed on the channel drainage facilities on the dam along Yaryginsky proezd.

Source: Gorodskiye Novosti