HOW THE DNIESTER HYDROPOWER AFFECTS THE STATE OF THE DNIESTER: ASSESSMENT BY MOLDOVAN AND UKRAINIAN EXPERTS

Posted on 17.12.2019

A large-scale analysis of the effects of the hydropower cascade on the hydrological regime and ecosystems of the Dniester basin, as well as on the water use by the population in the river basin, has been completed.

In this report, you can learn about how the state of the river and its inhabitants as well as the water use (e.g. for drinking and irrigation) have changed due to the redistribution of the Dniester water flow.

Should we abandon the use of the Dniester for hydropower and begin the gradual liquidation of the existing reservoirs?

What specific recommendations will be included to the management plan for the Dniester basin, according to the framework EU Water Framework Directive being implemented by Moldova and Ukraine?

The full version of the report will give you an answer to these questions.

 

Effects of the construction and operation of reservoirs and recommendations for further actions

 

The main effects of the construction and operation of reservoirsRecommendations for conducting additional researchRecommendations for exploring opportunities or taking corrective measures
The effects of structural changes resulting from the construction of reservoirs on the aquatic environment and biotic communities
Decreased suspended solid runoff downstream of reservoirs up to the Dniester deltaStudy of long-term changes in runoff and balance of heavy particle-size fractions of river sediments (sand and gravel)Development of a strategy for regulating solid runoff (sediment) in the Dniester basin
Change in the thermal regime of the transboundary section downstream of HPP-2Studying the possibility of water discharge from various depths of the Dniester reservoir
The development of macrophytes, the overgrowing of the channel and flood lakesQuantitative assessment of the extent of channel bedding and its implications (oxygen regime, secondary pollution)An increase in the stocking of the Lower Dniester by an obligate phytophage – grass carp
Change in the species composition of invertebrates (replacement of rheophilic species with limnophilic species), increasing the total number and biomass of macroinvertebrates, worsening the living conditions of sensitive taxa (decreasing EPT index)Standardized sampling of macroinvertebrates from various substrates and banks at different distances from the HPP-2 dam and downstream of the Dubossary reservoir (in the Reut River influence zone).

 

Study of the size and age structure of populations of dominant mollusk

species depending on temperature changes

Decreased cross-border zooplankton productionSpatial and quantitative assessment of the state of zooplankton at different distances from dams
Change in the species composition of ichthyofauna, reduction in stocks of commercial species, reduction in the number of rare and endangered speciesAnalysis of the prevalence of invasive and invading species in the Dniester basinPreventing the spread of invasive species
Influence of diurnal runoff fluctuations on the state of the transboundary site
Uneven intraday runoff fluctuations downstream of HPP-2Study of the intraday runoff fluctuations over a longer (representative) period of time.

 

Study of intraday variations in water quality in the downstream of HPP-2

Setting up bilateral automated monitoring of the level and flow rate of water downstream of HPP-2.

 

Inclusion of restrictions on the minimum value of instant release at HPP-2 in the Operating Rules of Dniester Reservoirs

Uneven intraday fluctuations in temperature, water level, and drainage of channel parts in the transboundary sectionStudy of the dependence of aquatic communities and aquatic organisms downstream of HPP-2 on daily fluctuations in water level
Long-term changes and intra-annual redistribution of runoff
Reduction of maximum flow rate in reservoirs’ downstreams (flood control)Development of modeling for an accurate forecast of the hydrological situation
Increase in the minimal runoff in reservoirs’ downstreams and ensuring guaranteed flow rates at water intakes and the needs of irrigated landsRegular updates of medium- and long-term forecasts of water consumption in the Dniester basin.

 

Study of the water intake related problems on the left bank of the Dniester (including degradation of the stream channel) and the city of Odessa (possible impact of surge phenomena at low flow rates)

Strict enforcement of the Operating Rules for guaranteed water supply and irrigated agriculture in dry years.

 

Implementation of the “Aquaproject” Institute project proposal to ensure the water level at the Chisinau water intake

Cutting off the peak flow rates and transformation of the spring flood regime during environmental and reproductive releases.

 

 

Deterioration of fish spawning conditions, bird habitats, ecosystem conditions in the Dniester delta due to a decrease in flooding of the plains

Quantitative analysis (modeling) of the processes of flooding of floodplains at different runoff volumes and surge and offshore phenomena.

 

Studies to update data on species diversity and ichthyofauna production, occurrence of rare and endangered fish species, assessment of fish stocks and the status of spawning grounds of lower Dniester

Steps to enable the water level rise of the Dniester reservoir to the top mark (dam repair, removal of existing dams and prevention of the construction of new facilities between FRL and SRL).

 

Further optimization of regular flushing of the riverbed and floodplains and of the spring ecological and reproductive release.

 

Development of measures for the protection of rare and endangered fish species of the Lower Dniester, restoration of spawning grounds, and regulation of commercial and recreational fishing.

 

Incentivization of fish-breeding enterprises for stocking of natural reservoirs with zanthe, sabrefish, and other commercial and rare species.

 

Creation of artificial meadow spawning grounds in the Dniester basin to ensure spawning of phytophilic species.

 

It should be noted that this report reflects data of the analysis of the effects of the operation of hydropower facilities. Other factors influencing the river: pollution by industry and sewage, climate change, construction, bank protection, etc. are discussed in the Transboundary Dniester River Basin Management Plan (a draft document “part 1” published at https://dniester-commission.com/en/news/experts-are-invited-to-comment-on-the-dniester-basin-management-plan/).

Infographics to the report (in Russian):

  1. History and goals of the Dniester HPPs and reservoirs;
  2. Distribution of river flow and its impact on aquatic organisms;
  3. Effects of the Dniester HPPs on the environment;
  4. Effects of the Dniester hydropower plants on daily fluctuations of the river flow;
  5. Effects of the Dniester cascade on water management.