Rehabilitation of the Zavyalovo Lake Ecosystem

In August 2022, the Ministry of Natural Resources and Environmental Protection of Altai Krai selected the general contractor to carry out works for the project “Clearing Lake Zavyalovo in the village of Zavyalovo, Zavyalovsky District, Altai Krai”. The contractor JSC “SIBGIDROMEKHSTROY” is carrying out the gravity dewatering of sediment and sludge. 

The project involves clearing the lake to eliminate the threat of ecosystem degradation, improve water quality and preserve its potential for water management use. The planned measures will reduce the negative processes currently observed in the lake (siltation, overgrowth and shallowing), restore natural water exchange and preserve the possibility of using the water body for the domestic needs of the population and recreation.

The clearing of Lake Zavyalovo in the village of Zavyalovo will be carried out in three stages over a total area of 82.8 ha, with the excavation of 326 813.5 m3 of soil. Taking into account the technological break, the works will take 25 months, with a budget of 241 million roubles.

According to the project, some of the works (disposal area No. 1) must be carried out within the lake’s water protection zone and coastal protective strip. Activities in this zone are restricted by the legislation of the Russian Federation, and erodible soil cannot be placed in disposal area No. 1. However, provided that water protection requirements are observed, the excavated soil can be placed in geotubes.

The dredger pumps bottom sediments mixed with water directly into the geotubes. Thanks to their design and special pore system, the geotubes retain sludge particles inside the container and drain free water from it, allowing the water to flow back into the lake.

Filled geotubes form highly strong and stable structures that will be used as protective reinforced-soil structures. The dewatered soil can be stored in these geotubes indefinitely, as it will not be moistened or washed out by precipitation, floods or other phenomena and, most importantly, will be completely safe for the environment. Therefore, after the works are completed, during the reclamation of disposal area No. 1, the geotubes will be left in place and the previously excavated topsoil will be placed over them and seeded with perennial grasses. The dewatered bottom soil from disposal areas Nos. 2 and 3 will be used to meet municipal needs for road construction and maintenance.