Impact Mitigation

In order to reduce the impacts which the construction of the small hydro power plants could have on the natural environment, several measures have been taken. Please read the following paragraphs for more information.

The residual discharge, or also called reserved flow, is the discharge of the water stream that remains in the water-stream bed after the water tap for the turbine and before the turbined-water return.

Indeed water is tapped from the water stream, led to the turbine and turbined before returning to the water-stream bed, but downstream from the tap.
A residual discharge is meant to:

  • assure fish survival
  • feed underground waters
  • favour species diversity
  • valorise landscape
  • create alluvial spaces
  • assure cleanliness of water streams

© ESHA – European Small Hydropower Association

In order to eliminate the probable impact on the fish through interruption of the continuity of watercourses which may result in reduced possibility for migration and consequently separation of the population and reduction in their vitality and abundance, the project includes designing and establishment of fish paths on water intakes at Brajcinska Reka and river Stanisar.

Detailed specification of these constructive segments of designing on the two intakes will be subject of further phases of designing of the mentioned facilities. The practical implementation of this design measure, through the construction phase, will contribute to the reduction of the potential negative impact on the fish stock in the course of the operational phase of the SHPP.
Fish paths are easy to implement, primarily due to (i) relatively simple engineering technology required for their construction, (ii) use of natural materials, and (iii) availability of manuals for their construction, functioning and maintenance (Therrien & Bourgeois 2000). Operational parameters of fish paths concerning the water flow rate, zones of turbulence, opposite currents, tangent flow, etc., will have great influence on the efficiency of the path.
(© ESHA)

Construction works at the location will include execution of earth and concrete works related to the construction of facilities and auxiliary infrastructure of SHPP.

In the frames of the established construction site and its surrounding, there will be movement of construction mechanization and labour. The highest level of this type of noise reaches 80 – 90 dB (A). Application of adequate standardized operational activities and measures during construction works will result in compliance of noise levels with the emission limit values. The main source of noise emission from the standard operational SHPP is the hydroelectrical unit, i.e. electric mechanical equipment accommodated in powerhouse, namely: generator, turbine, etc. Modern technology for this type of equipment manufacturing, which observes production standards for achievement of very low margins of tolerance, installation of sound insulation materials / elements in turbines, etc. enables reduction of noise at the very source (equipment) in the powerhouse to the level of 70 dB, which is subject to incorporation of construction and structural measures for sound insulation enables further reduction of noise levels outside the facility to the level which is almost undetectable for the population.
As a result from the nature of the locations and its distance from the main noise sources, the levels of noise within the project areas are within the ambient levels and within the maximum permissible limits, without intensive constant presence of noise generated by anthropogenic sources and activities.
(from the Environemt and Social Impact Assessment).