The future Kambar-Ata HPP-1 is threatened by an ancient landslide

Last week, public hearings were held in Bishkek on the construction project of the Kambar-Ata HPP-1 on the Naryn River. The discussion, which took place in a constructive but tense manner, revealed a number of serious concerns on the part of the public and independent experts. One of the topics of discussion was geological risks, in particular, the threat of large–scale landslides.

The participants of the hearings were particularly concerned about the possible impact of the future reservoir of the Kambar-Ata HPP-1 on the stability of slopes in mountainous areas. An expert from the Geopribor Scientific and engineering center drew attention to the presence of an ancient landslide with a volume of about 50 million cubic meters in the upper reaches of the dam, in the area of the target. According to him, seasonal fluctuations in the water level in the reservoir – filling in the fall and triggering by spring – can lead to the activation of this giant massif. The danger was also noted in the lower reaches, at the confluence of two rivers, where a similar process can lead to congestion of the channel. As an example of a possible scenario, the disaster in the Pamirs in Tajikistan was mentioned, where a landslide blocked the river, forming Lake Sarez. Gypsum and rock salt deposits lying at the base of the dam were named as an additional risk factor, the dissolution of which can cause the development of karst processes and subsidence of soil.

Representatives of the project team and international consultants, in turn, assured that these issues are in their field of view. They emphasized that the current stage is a feasibility study, which is only the first of three design stages. According to them, the identified risks will be studied in detail at subsequent stages. In particular, it is planned to carry out drilling operations and create a seismic monitoring network to obtain accurate data on the geological situation. The experts noted that on the basis of this information, the necessary compensatory and protective measures will be developed.

In addition to landslides, other pressing issues were raised at the hearings. Members of the public expressed skepticism about the assessment of seismic hazard, referring to recent statements by the President of the National Academy of Sciences of the Kyrgyz Republic about the need to conduct preliminary studies on seismic microdistricting. The frequency of recurrence of strong earthquakes every 475 years, indicated in the report, was questioned.

Local residents, in turn, talked about a possible change in the microclimate, which could lead to the drying up of springs and the reduction of pastures, and also insisted on job guarantees at the construction of hydroelectric power stations for the population of nearby villages. As a result of the discussions, it became obvious that, although the developers demonstrate readiness for dialogue, many key issues of safety and the impact of the project on nature and people’s lives require further, deeper study.

Alexander Eskendirov (Rivers.Help!)

Original (in Russian): Будущей Камбаратинской ГЭС-1 угрожает древний оползень