Use this url to cite publication: https://hdl.handle.net/20.500.12259/84517
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Impact of small hydropower plant on biotic environment
Type of publication
Tezės kitame recenzuojamame leidinyje / Theses in other peer-reviewed publication (T1e)
Title
Impact of small hydropower plant on biotic environment
Is part of
Nordic water 2012 : catchment restoration and water protection : XXVII Nordic hydrological conference : abstracts / editors : Ritta Kamula, Bjorn Kløve, Hanna Arola. Oulu, 2012
Date Issued
Date Issued |
---|
2012 |
Publisher
Oulu, 2012
Extent
p. 184
Field of Science
Abstract
In pounded reaches above HPP dams, habitats of low Fr number (0.04>Fr>0.0007) were created and negative impact of the dam was observed. The data obtained shows that investigated sections differ in terms of composition and relative abundance of different taxa of macroinvertebrates. Compared to reference conditions (site no influenced by dam), macroinvertebrate samples from the sites below dams had relatively more pollution tolerant Chironomidae larvae and Mollusca, and fewer more pollution sensitive taxa EPT Plecoptera, Ephemeroptera and Trichoptera. HBI index below HPP dam sites was finding worse in comparison with natural (control) sites investigated.
Segmentation of river channels into dammed and undammed reaches results in the changes in integrity of free-flow conditions and greatly disturbs the hydrological regime, coherent with both transport and retention of suspended sediments ant nutrients. The impact of a small hydropower plant (HPP) on the environment, particularly in downstream reaches was investigated in four Lithuanian rivers and involved 17 dams. The height of the dams and the capacities of their reservoirs ranged from 2.25 to 14.50 m and from 28xl03 to 15.500xl03 m3 respectively. To determine the concentrations of suspended solids (SS), total nitrogen (TN), and total phosphorus (TP), water and ground samples were taken about 50 m from each dam, both upstream (reservoir) and downstream (river). Benthic macroinvertebrates and a range of environmental variables were sampled at 3 study sections of each dam: control point, HPP reservoir and below HPP dam. The impact on biotic environment quality was also estimated by the ecohydraulic parameters - Froude Numbers (Fr) and Hilsenhoff biotic indexes (HBI). It was established that construction of HPP dams substantially changed natural regimes of SS and spread of invertebrates and also had negative influence on the abundance and taxonomic composition of macrozoobenthos. All the reservoirs had been trapped most SS including the finest one. As a result, the percentage of the particles with diameters <0.01 mm in the reservoir bed substrates increased about threefold in proportion to that in the river bed ones. The direct correlation with the coefficients ranging from 0.35 to 0.94 was established between the reservoir capacities and the deposited amounts of these particles. Flood water delay in the reservoir determined reduced concentrations of SS. The TN and TP concentrations decreased by about 11-13% only when the water was delayed in the pond cascades.
Type of document
type::text::conference output::conference proceedings::conference paper
Language
Anglų / English (en)
Coverage Spatial
Suomija / Finland (FI)